Results tagged “Jessica Snyder Sachs” from Articles by Jessica Snyder Sachs
Copyright Jessica Snyder Sachs, as first appeared in Popular Science
LIKE A COWBOY loosely holding the reins, Larry Weatherman steers up Deer Creek Road with his left hand on the wheel, his right arm ready at his side. His upper body rocks with the motion of the pickup as he navigates the dirt road's gauntlet of potholes and rocks. Since his retirement from the Missoula County Sheriff's Department in 2000, Weatherman has adopted the bushy white mustache and Stetson of a gentleman rancher. But on a snowy Saturday in March, he has driven 50 miles down from his 20 acres above Montana's Seeley Lake to take a visitor into the forlorn woods that served, three decades ago, as the dumping grounds for Montana's most notorious serial killer.
A gust of snow hits the windshield. Through the swirl, Weatherman spots a narrow break in the pine and fir trees lining the road. He pulls into a shallow ditch and opens his door. "He liked to take his girlfriends up here to party," he says.
Weatherman was a young officer in 1974 when he investigated the first in a series of gruesome murders that ended a way of life in Missoula, a place where people had left their doors unlocked and women felt comfortable walking home alone from the local bar. The first victim was a preacher's wife found gagged, bound, and shot in the basement of her home, her husband's handgun jammed between her legs. In addition to questioning the husband, Weatherman briefly suspected a high-school boy who neighbors had spotted in the victim's backyard that day. A grand jury found insufficient evidence to charge either suspect.
Over the next 12 years, the seemingly random murders continued. Three teenage girls and a married couple were killed, and the town suffered a spate of home intrusions thought to have been thwarted rapes. Then the improbable happened. In 1986 a would-be victim, already trussed and stabbed, managed to break free and kill 30-year-old Wayne Nance in a bloody struggle. Nance, a baby-faced furniture deliveryman and part-time bouncer, was the high-schooler Weatherman had suspected in 1974. Postmortem searches of Nance's bedroom and his father's house uncovered evidence of at least three additional murders and of other break-ins.
But hope for further information about the murders died with Nance. Weatherman was left with the unidentified remains of two young victims. One of them was "Debbie Deer Creek," a teenager whose skeleton he had chiseled out of a frozen grave alongside Deer Creek Road some 21 months before Nance's death. Several strands of dyed hair enabled Weatherman to connect her to a photo of a dark-haired drifter that bar patrons knew as "Robin" before she disappeared a few weeks after moving in with Nance. Weatherman sent out scores of bulletins to the FBI and regional law-enforcement agencies. But the girl's picture and street name failed to locate family.
It would take more than hair strands and a faded picture to identify Debbie Deer Creek. It would take technology--still two decades away--that could extract minute amounts of fractured DNA to reveal an indelible link to a victim's family. It would take one brother's unceasing search to find out what happened to his runaway sister. And perhaps most of all, it would take the U.S. Department of Justice's slow but horrifying realization that there may be far more serial killers on the loose in America than anyone had ever expected.
For two decades, a facial reconstruction made from Debbie Deer Creek's skull sat on top of Weatherman's bookcase facing that of another girl, "Christy Crystal Creek," discovered by a hunter two miles farther up the same mountain road above Nance's home. "I knew somebody once cared for them," he says.
The Silent Missing
Debbie and Christy are far from alone, and the same might be true of the likes of Wayne Nance. In a recent issue of the scientific journal Homicide Studies, criminologist Kenna Quinet wrote that conventional calculations seriously underestimate the number of serial murder victims. "The problem may be 10 times worse than we imagined," she says. Instead of 180 victims a year in the U.S., there may be as many as 1,800.
Quinet, a nationally renowned homicide expert at Indiana-Purdue University Indianapolis, bases her conclusions on simple arithmetic. According to the Department of Justice, up to 40,000 sets of unidentified human remains sit in police-evidence lockers and medical examiners' offices across the nation. If resolved cases are any guide, the majority are murder victims. Against this, Quinet factors the homicides suspected in a significant proportion--as much as 20 percent--of missing-person cases, more than 100,000 of which remain open at any time in this country.
Quinet bolsters her new estimates with evidence of the lengthy careers of the serial killers who are eventually caught and convicted. "Typically, these killers operate under the radar for years, even decades," she explains. Studies show that male serial killers average six to eleven victims over a nine-year period. Female serial killers (primarily health-care workers) average seven to nine victims over the same window.
And that's just those who get caught. "I would guess that at any given moment," she says, "there are at least two people in each state committing serial murder"--more than 100 serial killers on the loose. Washington State is currently tracking at least four: the so-called 22-Caliber Killer, the Index Killer, the Lewiston Valley Killer and the Snohomish County Dismemberment Killer.
Meanwhile, other serial killers are operating too randomly or infrequently to generate a pattern or are cunning enough to prey on those unlikely to be missed. Quinet calls these possible victims America's "missing missing," the tens of thousands whose disappearance is not taken seriously by law-enforcement agencies. They include those that law enforcement assumes to be "missing" by choice: runaways, transients, prostitutes, and anyone who has an outstanding bench warrant. (The irony, Quinet notes, is that the warrant can be for the missing person's failure to appear in court.)
John Morgan, deputy director for science and technology at the National Institute of Justice, the research arm of the Department of Justice, believes that part of the problem is the increasingly transient nature of American life. "We live in a more fragmented society," he says. "A lot of homicides that occur involve strangers." And for a greater number of the victims, living far from their hometowns and disconnected from a social network, their absence won't be noticed, or they will be dismissed as having simply moved on. As a result, Morgan says, it's now less likely "that a particular homicide will be resolved and the killer brought to justice."
The first step in solving these crimes--even before a detective can start to connect the clues--is connecting the bodies to the missing. "After all," Quinet says, "it's hard to conduct a murder investigation when you don't know who the victim is."
One in a Million
Derek Bachmann was 14 in 1984 when he helped his 15-year-old sister, Marci, pack her bags and run away from their Vancouver, Washington, home. "She told me my stepfather was touching her, making her touch him," he recalls. "I told her, 'You're right, you need to get the hell out of here.' " That was the last time he saw her. "The fact that I helped her pack has always haunted me," says Bachmann, now a Web marketer living outside St. Louis. "I mean, there were five different serial killers in the Northwest at the time." (In fact, there were at least eight.)
In 1991 Bachmann began to search for his sister, if only to confirm his fears. "I think I knew that if Marci was alive," he says, "she would have contacted me." He called and wrote to scores of homicide task forces and vice squads across the country, the latter in case Marci had fallen into streetwalking. "I tried everything," he says. "I tried psychics. I hired a private investigator, spent $10,000 on him. Got nothing."
By 2000, Web sites such as the Doe Network offered Bachmann a new resource. Maintained by amateur detectives and families of the missing, these cyber-bulletin boards feature case histories and, when possible, photos or artist re-creations of the unnamed dead, typically gleaned from news and police reports. Bach-mann began spending all-nighters at his computer. His obsession put a strain on a short-lived marriage, he admits with a slow shake of his head. "The atrocities I've seen looking for my sister."
Among them was a flower-adorned memorial page dedicated to a girl named Robin, with a photo of a dark-haired girl in glasses under the banner "Do you recognize this face?" Bachmann looked again. There was something familiar about the mouth and nose. "I showed it to my relatives," he recalls. "They said, 'No way. Marci never wore glasses.' " Besides, the hair color was wrong. Still, a few months later, he dialed the number provided for the Missoula County Sheriff's Department and left a message for Captain Greg Hintz. No return call.
When Marci left home in 1984, Seattle's Green River Killer was at the height of a spree that would eventually claim the lives of as many as 49 women, mainly prostitutes and teenage runaways. Bachmann wrote to King County detective Tom Jensen, head of the Green River Task Force, who promised to compare Marci's dental records with the impressions taken from the four unidentified victims in his custody. But no dental records were available, and Jensen added Marci's file to those jamming his filing cabinets.
In 2001, King County sheriff's deputies arrested 53-year-old truck painter Gary Ridgway for the Green River killings; two years later, he was sentenced to 48 consecutive life terms. The work of the Green River Task Force was finished. But Jensen still had more than 100 missing persons and suspected homicides in his files.
Jensen's captain assigned three detectives from the disbanded task force to review the cases and make a final effort to close them. And so, in the summer of 2005, detective Raphael Crenshaw called Derek Bachmann in Missouri: Was Marci still missing? Crenshaw told him about a new program that attempted to match family DNA against unidentified remains. Bachmann was eager to supply his, but Crenshaw also needed samples from his parents.
"I knew my dad would take a lot of convincing," Bachmann says. But he did convince his mother, who still lived in Washington. The next week, she rubbed a cotton swab against the inside of her cheek, sealed it in a plastic baggie, and sent it to the sheriff, who shipped it on to Texas.
Connecting DNA's Dots
When Nance and Ridgway were going about their grisly business, no method was available to connect the missing, like Marci Bachmann, to the dead. But there's now a lab, in Fort Worth, Texas, that can close the gap.
It's another March morning, and a steady rain has Fort Worth's Trinity River running high through the city's cultural district. On the other side of Camp Bowie Boulevard, employees and students are leaping over the ponds growing in the driveway of the University of North Texas Health Science Center. The third floor of this beige stucco high-rise is home to the university's Center for Human Identification, the only academic DNA lab in the country dedicated to identifying human remains.
Photo of Dixie Hybki and Rhonda Roby at the Center for Human Identification courtesy of the University of North Texas Health Science Center
In 1989, molecular biologist Arthur Eisenberg began using DNA to settle questions of identity in cases ranging from paternity to homicide. For the next decade, Eisenberg developed many of the procedures and standards used in DNA testing today. Around 2000, he began to focus on missing persons, and in 2001, he and his staff built a state DNA database. Since then, the center's capacity has grown to handle cases from across the country.
The victim specimens that arrive at the center range from well-preserved femurs (thigh bones) to broken slivers of bone that have been sitting inside police warehouses for decades. It's far easier to extract DNA from recent samples, and the center prioritizes easy identifications. Well-preserved or relatively fresh remains for which a family connection is already suspected take precedence over colder cases with no leads. The center has been able to solve one in every four of its cases.
Still, it's the difficult cases--the shots in the dark--that tantalize, says the center's project manager, Rhonda Roby. She speaks from experience, having spent her career developing methods for extracting DNA from severely degraded remains. In 1991 Roby began working in the Office of the Armed Forces Medical Examiner, where she helped develop methods for identifying the skeletal remains of American soldiers from Vietnam, Korea and World War II. In 2001 she flew to New York City to help set up protocols for the unimaginable task of identifying more than 20,000 pieces of human tissue retrieved from the ruins of the World Trade Center. She has also helped identify victims of Chile's Pinochet regime and, in a curious aside, the remains of Nicholas II and the Romanov family of tsarist Russia.
In 2004, shortly before Roby's arrival, the center achieved its first successful DNA extraction in an extremely cold case. The remains--a slender, yellowing femur--had arrived by FedEx. Forensic analyst Lisa Sansom cataloged the bone in the center's database as F2775.1EC and carried it into the lab's bone room, behind a door flagged "Forensic Low-Copy Area. AUTHORIZED PERSONNEL ONLY." The amount of genetic material retrieved from old bone tends to be so small as to be easily overwhelmed by the ambient DNA of a floating skin flake or a saliva droplet. Inside the Low-Copy Room, analysts don full gowns, face masks and surgical gloves. A positive-pressure system keeps "dirty" outside air from flowing in, and analysts have their genetic profile entered into the center's DNA database so that those will be excluded from target sequences.
The work differs from the kind of DNA fingerprinting used to identify biological evidence left at a crime. It is extremely difficult--sometimes impossible--to extract conventional nuclear DNA markers from an old bone. The center has become skilled in extracting and analyzing a hardier but less-known source of DNA: that of the mitochondria that reside in our cells.
Except for identical twins, each person's nuclear DNA is unique. But each of us has another set of DNA located outside the cell's nucleus and inside the mitochondria, the tiny organs that supply a cell with energy. We inherit mitochondrial DNA, known as mtDNA, directly from our mothers, and we share it with our siblings. It's not unique, but mtDNA is enough to narrow the search for a victim's family.
Sansom spent almost an hour scrubbing and sanding the femur's surface before attempting extraction. Few of the bones here contain marrow, which dissolves in the first two or three years after death. F2775.1EC had spent some 20 years in a box inside a police warehouse, so DNA would have to come from the scant cellular material inside the bone's white scaffolding.
She used a woodworker's dremel to cut a rectangular window in the thickened area of bone just below the femur's rounded head, where the thigh muscles once attached. Next she chilled, pulverized, and blended the sample inside a freezer mill loaded with sterilized ball bearings. Using an automated chemical process, she broke open the bone cells, released their genetic contents, and washed, concentrated, and purified the extract.
For genetic analysis, Sansom first had to increase the DNA to detectable amounts using a process called DNA amplification. Forensic software translated the results into a four-color graph of peaks and troughs. Drawing on her training and experience, she translated each graphic peak into one of the four nucleotide letters in the DNA alphabet. It took her about a week to process sample F2775.1EC.
When the amplification signals aren't clear, the chances for a reliable match plummet. In the worst case, the sequence data prove ambiguous, and workers must repeat the extraction and analysis. Sansom got her sequence on the first try. She uploaded it to the center's DNA database. No hits. Then she uploaded the data to the FBI's national missing-persons database. Again, no hits. Not yet.
Scaling the Backlog
In 2004 the center received a major investment to help realize Arthur Eisenberg's goal of establishing a National Center for the Identification of Human Remains. It was the first of several National Institute of Justice grants given over a five-year period totaling more than $7 million. The center's mission was to perform DNA testing on unidentified skeletal remains and "family reference" samples free of charge for any local or state law-enforcement agency that requested it. It's now a clearinghouse at the heart of an effort to address the thousands of missing persons and unidentified remains discovered each year--what the justice department calls "America's silent mass disaster."
"The World Trade Center attack devastated this country with its massive loss of life," Eisenberg says. "But if people only knew how many more unidentified murder victims there are . . . If you go back even 20 years, there are literally hundreds of thousands of families who have missing loved ones." Even with generous funding, progress will ultimately hinge on making identifications cheaper, faster and more definitive, he adds.
Laboratories such as the Center for Human Identification will be swamped now that more states mandate the collection of family-reference samples with missing-person reports. The center, Eisenberg says, must advance the technology used to identify human remains as it goes. By way of example, he cites a new program that can use broken bits of traditional nuclear DNA to identify weathered bones.
The tests scan some 40 lengths of highly fragmented DNA for single-nucleotide polymorphisms (or SNPs, pronounced "snips"), one-letter variations in the genetic code. The SNPs are then combined to create unique DNA fingerprints. If the center's tests are successful--and Eisenberg says they're making rapid progress--SNPs will allow forensic analysts to identify old bones more reliably than they can using mtDNA. "If SNPs pans out, it will be another revolution in how we deal with homicide," the National Institute of Justice's Morgan says. "There will no longer be a reason to have unidentified remains."
In addition to testing such systems, the Center for Human Identification is collaborating with other institutions in the effort to improve identification. It is working with the University of Tennessee, for example, to automate DNA analysis and speed up identifications for all the investigators and families tortured by a cold case. Right now, the center's tests produce a chart of several hundred peaks and valleys that a trained forensic analyst must read one nucleotide "letter" at a time. A second analyst then reads it again to verify its accuracy. Although complete automation of the process remains a distant dream, Tennessee scientists have designed a software program that can read "perfect" sequences, or unambiguous graphics. Soon it may be able to replace the second read and thus slash personnel costs and turnaround time.
But extracting and reading DNA from unidentified remains is only half the challenge. That DNA must get linked to the right missing person. What the country has sorely lacked, Morgan says, is a central repository for information such as photos, fingerprints, dental records, DNA sequences and other identifying information on both missing persons and unidentified victims. Make that database searchable, and it becomes a profitable tool for homicide detectives. Open it to the public, and it becomes a merciful resource for the thousands who currently spend their nights combing disturbing Web sites.
In 2005 the U.S. Attorney General's office formed a Missing Persons Task Force to develop the National Missing and Unidentified Persons System, or NamUs (identifyus.org). In 2007 the first part of the system--a searchable database of unidentified human remains--went live. Last year, the program opened up a national database of missing-person reports. And later this year, NamUs plans to connect the two, with a cross-searchable database that automatically matches the missing and the dead.
Before the NamUs database is complete, though, researchers at Fort Worth's Center for Human Identification have to rely on meticulous information-gathering and luck. The center has put together a DNA-collection kit for family members of the missing, which it sends out free of charge to the nation's police and sheriff's departments. Law-enforcement officers mail cheek swabs collected from the family back to the center, where workers analyze them in batches of up to 80 to yield both nuclear- and mitochondrial-DNA profiles of parents and siblings.
As each family member's DNA fingerprint comes off the line, it too goes through the databases to search for approximate matches among the dead. The process is spellbinding, claims forensic analyst Melody Josserand. Any of thousands of mysteries could be solved at that moment. "Even though I do searches 30 or 40 times a week, I've never walked away," she says. "I sit here with bated breath."
Josserand remembers the day in March 2006 when Unidentified Person F2775.1EC flashed across her screen. She had just uploaded family-reference sample F3352.1US, submitted by the King County Sheriff's office. Like the reels of a slot machine, twin columns of numbers rolled down her monitor. The rows for six out of six mitochondrial-DNA base pairs flashed green. A perfect match. But mtDNA alone, she knew, wasn't definitive. Fortunately, back in 2004, Sansom was able to pull seven markers for nuclear DNA from the victim's bone sample. Josserand compared the family-reference sample with that. All of them matched.
Josserand retrieved the folder for Unidentified Person F2775.1EC and checked it against the file for the family-reference sample. "The metadata all matched," she says of Debbie Deer Creek's physical descriptors: female; approximate age, 17; weight, 125; height, 5'7". Estimated date and place of death: 8/19/1984, Missoula, Montana.
From the missing-person report, Josserand read the name: Marcella Bachmann. Last contact: 5/1984, Vancouver, Washington. "All I could think was, 'I wonder how this poor girl got from here to there?' " she says. Still, certainty depended on more family samples, ideally from the biological father. So the call went out to Derek Bachmann through Detective Crenshaw in King County. Crenshaw didn't say anything about the bone from Missoula. "I gave him the spiel I give everyone, so as not to get hopes up," he says. " 'The lab wants more DNA samples to make sure that if there's a hit, they can narrow it down.' "
"I called up my dad," Bachmann says, "and flat-out told him, 'You have to do this. I have to know.' "
On March 22, 2006, the Center for Human Identification received two FedEx envelopes, one containing a cheek swab from Bachmann, the other from his father. The father's nuclear DNA matched all of Debbie Deer Creek's nuclear-DNA markers. To underscore the identification, Derek's mtDNA, like that of his mother, proved identical.
Following protocol, the Center for Human Identification relayed the news to the National Center for Missing and Exploited Children, which in turn called Missoula and Captain Hintz, who had submitted Debbie Deer Creek's femur after Larry Weatherman's retirement.
"I'll never forget his call," Bachmann says. "I was in a poker tournament and had to step outside." As Hintz spoke, Bachmann suddenly realized that he didn't want "closure" after all. "I instantly grasped the idea that he was finally calling back about the Web-site photo. I told him I'd been thinking about it, that the picture couldn't have been my sister," he recalls. "Well, he disabused me of that."
Photo of Derek and Marci in 1971 courtesy Derek Bachmann; Photo of Wayne Nance and "Robin" courtesy of Missoula County Sheriff's Office
The Final Identification
Almost exactly two years later, on this snowy March day in Missoula, Weatherman waits for Derek Bachmann to step out of the county truck they have borrowed for their second visit to the place where Weatherman unearthed Marci's frozen remains on Christmas Eve 1984.
Bachmann shivers inside his leather jacket. The snow quickly saturates his sneakers as he follows the retired lawman a quarter of a mile through the woods to a bluff above the Clark Fork River. A grove of spindly conifers still surrounds the mossy depression that once held Marci's body. "It was a lot harder the first time," Bachmann says of the visit. "Yeah," Weatherman acknowledges. "That was a hard one for you."
From beyond the bluff comes the rumbling sound of construction--or rather, deconstruction--echoing up from the Milltown Dam below. A strip of orange and yellow surveyor flags marks a path past Marci's gravesite to what will be a viewing platform directly above a river-restoration project. In addition to tearing out the old dam, the county plans to build a small park. Construction is due to begin in the spring. Bachmann has come back, in part, to ensure that nothing desecrates Marci's spot. Perhaps he can even persuade the county to raise a small memorial, he proposes. Weatherman nods in agreement.
"I suppose you're ready to put all this behind you," Bachmann offers as the men head back to the truck. "I don't suppose it ever will be," Weatherman says, "until we get Christy identified."
At press time, DNA from Christy's femur had been entered into the Center for Human Identification's database of cold-case remains, as well as the national DNA database. She's ready to be found.
Unlikely Partners in the Sea
Copyright Jessica Snyder Sachs, as first appeared in National Wildlife
Narwhals, among the Arctic mammals most threatened by global warming, may help scientists track temperature changes in otherwise inaccessible ocean depths
BIOLOGIST Kristin Laidre sits in her University of Washington office overlooking Puget Sound's busy Portage Bay. With little prompting she lets her mind drift to a much larger, colder bay some 2,500 miles to the northeast. "What stands out about Baffin Bay," Laidre says, "is how you can fly for hours over the dense ice, a landscape where you wouldn't expect a single living thing, and then you look down and see a small lead, a tiny crack in the ice, and there will be a narwhal."
On the most memorable occasions, Laidre and her colleagues have watched what they call the classic narwhal ménage à trois--two males crossing and rubbing their 6- to 9-foot-long tusks above the head of a bobbing female. "It's quite remarkable," Laidre says. Laidre has spent the past 10 years tagging, tracking and studying the narwhal--the Arctic's most specialized, range-restricted and northernmost whale. The narwhals of Baffin Bay account for 80 to 90 percent of a world population of 50,000 to perhaps 80,000. A second group, of around 5,000, inhabits the northern part of Canada's Hudson Bay. An even smaller population of unknown number lives east of Greenland.
The narwhals that winter in the deep water of central Baffin Bay get there by migrating thousands of miles from summering areas in the shallow bays and fjords of the High Arctic. Despite the extreme cold and ice cover, winter is a period of intense activity for this small, highly social whale. Winter is mating as well as feeding season, a time when narwhals consume the vast majority of their yearly diet.
On a typical winter day, narwhals dive almost continually to graze on the pitch-dark seafloor and there gorge on fatty, energy-rich Greenland halibut, or "turbot." Many dives reach down to 5,000 feet and last some 30 minutes. At such depths, narwhals are sustained solely by their highly oxygenated blood and muscles, the deep-sea pressures having collapsed their lungs. When they surface to breathe, as all whales must, narwhals zero in on small--sometimes fleeting--cracks in the thick winter ice pack. Open water can suddenly freeze during windless conditions and temperatures below minus 30 degrees F.
Come April, the ice pack begins to loosen, signaling the narwhals to begin their two-month-long northward migration. It's during this early spring window--when the ice has loosened but has not yet turned to slush--that Laidre flies east from Seattle to rendezvous with her longtime colleague, Mads Peter Heide-Jorgensen of Greenland's Institute of Natural Resources. "Our work has focused on gaining a fundamental understanding of how this animal uses its ecosystem," Laidre says. "Only then can we begin to suggest ways that it can be protected."
That the narwhal remains so little studied stems directly from the difficulty and expense of mounting research expeditions across Arctic seas, Heide-Jorgensen says. "I'm sure a similar effort on almost any other creature would yield a lot more data, but it's also gratifying to study an animal where every piece of information you learn is worth its weight in gold."
For starters, their team has documented the narwhals' faithfulness to their narrow migratory routes. They've also reported the Baffin population's need to consume some 880 tons of Greenland halibut daily each winter. Field observations and autopsies on hunter-harvested whales have likewise confirmed that narwhals eat surprisingly little during the milder summer months. "We don't know why, but narwhals depend on their wintering grounds to supply the bulk of their diet," Laidre says.
In 2008, Laidre and Heide-Jorgensen's research flashed briefly into public view with the publication of an international consensus report that ranked narwhals as edging out even polar bears as the Arctic mammal most vulnerable to climate-induced habitat change. According to the report, this extreme sensitivity to global warming stems directly from the whale's small range, narrow migration routes, limited world population and restricted diet. Combine these traits with the narwhal's low genetic diversity and, Heide-Jorgensen says, "I think you can understand what makes them so vulnerable."
Just how global warming will affect the narwhal's environment remains unclear. Counterintuitively, one possibility is that warming will further reduce the scant open water that ensures winter survival for narwhals. Such a cooling trend could result from the increased rainfall that global warming can produce in coastal regions. The increased influx of freshwater decreases ocean salinity, which can slow or shut down ocean currents that would normally deliver warmth from the Equator. In line with such predictions, in 2005 Laidre and Heide-Jorgensen reported that Baffin Bay sea ice cover had been steadily increasing since 1978. During this time, the percentage of open water at the end of winter had shrunk to an average of just one half of 1 percent. "Now that seems to have reversed," Laidre says of the last four years. "Instead we're now seeing less and less ice cover."
Unfortunately, increased open water could bring its own problems. One major concern is that rising water temperatures could render the narwhal's ecosystem less productive--particularly in regard to the cold-water turbot that provide the whale its primary food source. Another is the possibility that fishing fleets will begin entering the narwhal's previously ice-locked feeding areas. "Both Canada and Greenland have looked at extending their coastal fisheries offshore," Laidre says. "With reduced ice cover, that interest will only continue." Indeed, the international competition for nearby fisheries has been so fierce at times as to escalate into armed conflict. During the so-called Turbot War of 1995, the Canadian Coast Guard used machine guns and water cannons to disrupt and seize Spanish trawlers plundering Newfoundland's Grand Banks. Whichever direction global warming takes Baffin Bay, environmental shifts are already in motion. "The whole ecosystem is changing, not just with respect to narwhals," Laidre says.
Baffin Bay's narwhals may play a pivotal role in better understanding these changes. Over the past two years, Laidre and Heide-Jorgensen have used a grant from the National Oceanic and Atmospheric Administration to harness 10 narwhals with satellite transmitters. The transmissions relayed the animals' positions and surrounding water temperatures as the whales made thousands of winter dives to the bottom of Baffin Bay.
Laidre tracked the narwhals' daily movements from her computer monitor at the University of Washington's Polar Science Center. Now that the last of the transmitters has fallen away and sunk, she is beginning the daunting task of analyzing the temperature data with the help of the science center's oceanographers.
Preliminary analysis suggests that the whales are diving at fronts--areas with large and rapid temperature changes that stem from warm, upwelling waters. "On its own, these data aren't going to reveal anything about global warming," Laidre says. "But they can serve as a baseline for future studies, and, when combined and compared with historical data, they may show differences from the past."
Already the data transmitted from the outfitted narwhals are rivaling the meager information collected through far more expensive, manned expeditions that require research vessels to venture into iceberg-strewn waters, winch instruments into the deep on cables and then return months later with the hope of retrieving them.
Meanwhile, the narwhal's short-term prospects look good, with populations appearing stable in the decade since the governments of both Greenland and Canada forged hunting quotas with the region's native Inuit peoples. The Inuit harvest several hundred narwhals each year, both for the male's valuable tusk and for the nutritious meat and vitamin-rich skin that have long helped Arctic peoples survive on a diet largely devoid of fruits and vegetables.
Today, Arctic researchers can still watch thousands of migrating narwhals passing by their coastal camps in a single day--sometimes spaced apart only by the 9-foot-long tusks of the males. Heide-Jorgensen describes being awed by both the view from coastal cliffs and the sounds he hears from his tent under a midnight sun. He describes the noise of a narwhal surfacing to breathe as somehow both prehistoric and resembling the brake release of a diesel truck. "A kind of whistle that ends with an airy sigh," he says. "And that's when you forget how cold it is. It's just you and these ancient creatures with a life so special and isolated from anything else."
Jessica Snyder Sachs is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Farrar, Straus, and Giroux, 2007).
The Tale of the Tusks
Though technically considered "toothed" whales (as opposed to filter-feeding whales that have mouths lined with baleen), adult narwhals have no functioning teeth inside their mouths. The male's tusk, which grows as long as 9 feet, begins as one of six pairs of teeth inside the mouth of a fetus. Four pairs of those teeth disappear before birth, leaving two pairs. One of these develops into the cuspids, or "fangs," and the others into vestigial teeth. In males the left cuspid continues to grow outward in a counterclockwise spiral, emerging through the upper jaw and lip to form a spearlike tusk. Typically the right cuspid remains imbedded in the upper jaw, but about one in 100 males sports double tusks. Similarly, about one in six females will bear a single, shortened tusk.
Cetacean Senior Citizen
Although they live in a dangerous winter environment where the vagaries of sea ice can lead to sealed breathing holes and death from suffocation, narwhals, according to a recent study by Mads Peter Heide-Jorgensen of Greenland's Institute of Natural Resources and his colleagues, has determined that the animals nevertheless are among the longest-lived mammals.
To determine the age of narwhals, the researchers studied changes in eye chemistry that occur predictably as the animals age, using specimens from 75 dead narwhals collected in West Greenland in 1993 and 2004. The oldest of the whales, a female, was between 105 and 125 years old. The oldest male was between 75 and 93 years old. However, the animals in the study came from a heavily hunted population. "The maximum age in other narwhal populations with less disturbed age structure might be considerably higher," the biologists concluded in a paper published in the Journal of Mammalogy. "Maximum age also is likely to increase when more specimens are examined."
Biologists have estimated the life span for a number of whale species, and some of them, too, are long-lived. The oldest recorded orca, or killer whale, and the oldest blue whale were both 90; the oldest fin whale reached 100. The real Methuselah in the cetacean world is the bowhead, another species of Arctic seas; the oldest on record lived 211 years.
Two of the most familiar whales did not win the whale life span sweepstakes. Sperm whales, the species of titular interest in the novel Moby Dick, live about 70 years and humpbacks about 48.
Hospitals need to come clean about infections and what's causing them.
copyright Jessica Snyder Sachs, as originally appeared in The [Newark] Star-Ledger
Our neighborhoods are in a panic over news reports about MRSA, or methicillin resistant Staphylococcus aureus. There's no doubt that this nasty bug has moved into our communities and our schools. But the deadliest threat from MRSA--and an alphabet soup of other drug-resistant bacteria--remain behind the doors of our local hospitals. Eight-five percent of MRSA infections occur during or following a stay in a healthcare facility.
The sad truth is that our hospitals have become dangerous places to be sick. Even routine surgical procedures bring the risk of potentially deadly infections involving hospital-bred bacteria. Infections picked up in health-care settings kill an estimated 99,000 Americans each year, more than twice as many as die in car crashes. It's a problem that has grown dramatically worse by the decade, as our antibiotic-infused medical centers became breeding grounds for drug-resistant bacteria.
In addition to MRSA, other increasingly common hospital superbugs include a viciously toxic strain of Clostridium difficile, bred from the bacterium that commonly causes post-antibiotic diarrhea; vancomycin resistant enterococcus (VRE), a virtually untreatable bug bred from a harmless member of our intestinal microflora; and Actinobacter baumannii, another near-unstoppable microbe, this one recently introduced into our hospitals in the infected wounds of soldiers returning from Iraq, Afghanistan, and before that, Kuwait.
The good news is that a half century of dangerous secrecy is starting to come to an end. This year New Jersey joined New York and Connecticut in the ranks of at least 22 states with some sort of mandate for the reporting of hospitals infections. These laws represent a step in the right direction. But few ask hospitals to differentiate infections caused by "ordinary" bacteria and those caused by highly drug resistant superbugs. New Jersey is one of these exceptions, with a new law on the books requiring specific reporting of hospital MRSA.
The importance of such reporting laws goes beyond a consumer's desire to steer clear of a medical center plagued with abysmal infection control. Worse, fifty years of secrecy have left public health officials guessing as to the arrival and spread of deadly new strains of drug-resistant bacteria in our hospitals.
The current situation with C. difficile illustrates the problem. Since 2003, C. difficile deaths have dominated news in Canada and the United Kingdom. British tabloid headlines like "Toe Nail Surgery Nearly Killed Me" refer to the common scenario wherein someone checks into the hospital for a routine procedure, receives antibiotics, and promptly contracts this drug-resistant invader.
Public outcry in Canada and the UK produced tremendous political pressure to address the problem in those countries. Even today, British lawmakers are quick to call the government's health minister before Parliament for public castigation when quarterly hospital reports of either MRSA or C. difficile rates fail to show improvement.
Ironically, in 2005, medical detectives traced the origins of the toxic C. difficile strain wreaking havoc in Canada and the U.K. to the United States, where hospitals had been heedlessly experiencing deadly outbreaks for at least six years. "We had no idea what was going on," admitted the chief of infection control at the University of Pittsburgh Medical Center, which in 2005 belatedly reported that its own C. difficile death toll had begun a dramatic ascent in January 2000.
Once forced to examine and deal with their superbug problems, hospitals can make great strides. This month, a once-chastened University of Pittsburgh Medical Center reported that it has brought its C. difficile rates down by more than 70 percent with an aggressive combination of tactics that include requiring doctors to get permission from an antimicrobial management team before prescribing the kind of powerful antibiotics known to raze the body's good bacteria and, so, leave a patient vulnerable to C. difficile and other drug-resistant bacteria.
Once their dirty secrets are out, other medical centers can likewise begin sharing and comparing infection control efforts. To that end, the first round state laws requiring hospitals to report infections in a general way do not go far enough. Our state legislators need to ride the current wave of public concern about supergerms to pass further legislation requiring hospitals to report on infection problems on a bug by bug basis--starting with their most dangerous and drug-resistant bacteria.
Jessica Snyder Sachs, a contributing editor to Popular Science and Parenting magazines, is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World.[JUMP BACK TO HOME PAGE]
by Jessica Snyder Sachs, as first appeared in HEALTH magazine
How's your cholesterol? Here's a guess: If you're healthy, you probably have no idea. New surveys show women tend to be clueless about their risks of heart disease, especially when it comes to managing their cholesterol.
But this kind of ignorance is anything but bliss. The reason: The
artery clogging that makes heart disease the number-one killer of women
late in life begins much earlier--in your 20s, 30s, and 40s--and that's
when your cholesterol numbers may be sounding alarms. So, are you ready
to start paying attention? Here, the things all women need to know now.
1. High cholesterol is surprisingly common in premenopausal women.
Researchers with the Framingham Heart Study recently delivered a nasty surprise: Nearly a quarter of women in the study who are in their early 30s have borderline-high levels of bad cholesterol, as do more than a third in their early 40s and more than half in their early 50s. A third of women in all three age groups have low levels of good cholesterol.
Bad cholesterol, also known as low-density lipoprotein (LDL), contributes to heart disease by laying down artery-clogging plaque; good cholesterol, or high-density lipoprotein (HDL), helps clear it away. "The double whammy of high LDL and low HDL is particularly dangerous," says Framingham researcher Vasan Ramachandran, MD, of the Boston University School of Medicine.
2. Your doctor may miss the problem.
Though women are better than men about seeing a doctor regularly, the care they receive isn't as good when it comes to preventing and treating cardiovascular disease, according to new studies. "Perhaps doctors still haven't gotten the message that women need to control cholesterol," says Chloe Bird, PhD, author of one of these studies and a senior sociologist at the nonprofit RAND Corporation. Bird found that doctors are less likely to monitor and control cholesterol in women than in men, even when the women are at superhigh risk of heart attack.
Part of the problem, she says, may be that many women see only a gynecologist. This isn't to say that OB-GYNs can't be good primary care doctors, but you have to make sure the doc is willing to monitor your heart health, especially if you already have diabetes or a heart issue. That means she should order cholesterol checks as part of your regular blood work and discuss the results with you. What does "regular" mean? See "How Often Do I Need a Checkup?"
3. Your numbers may trick you.
Many people misunderstand the roles of so-called good and bad cholesterols, according to cardiologist and lipidologist Pamela Morris, MD, of the Medical University of South Carolina in Charleston. "What we've learned is that HDL and LDL are independent predictors of a woman's heart attack risk," she explains. "We see women with high HDLs having heart attacks when their LDL is also high, and we also see heart attacks in women with very low LDL but also low HDL."
What that means to you: It's important to keep track of both. A woman wants to keep her HDL above 60 (the level at which HDL helps prevent disease) and her LDL below 100. If your HDL drops below 50 or LDL rises above 160, you need to take immediate action. That may include an LDL-lowering drug such as a statin, and it definitely includes a commitment to a heart-healthy diet and lifestyle.
4. You may need an "inflammation" test.
The math used to estimate your heart disease risk is a little misleading. If your LDL rises above the danger line of 160 or your HDL drops below 50, the math says you have an elevated risk of a heart attack within 10 years. But that warning may actually underestimate your risks beyond 10 years, Morris says. So when she has a female patient with cholesterol numbers in the intermediate range--LDL above 130 or HDL under 60--she often takes a close look at the woman's whole-body inflammation level.
You can't see this kind of inflammation, but it's actually an independent measure of heart attack risk. You measure it by adding a test for high-sensitivity C-reactive protein (hs-CRP) to the usual cholesterol blood work. CRP, essentially a body chemical, usually rises anytime your body becomes inflamed. And since artery clogging is associated with inflammation, high CRP is viewed as a marker for clogged arteries. That means your C-reactive protein levels may help you and your doctor decide how aggressively you need to control borderline-high-cholesterol levels with drugs, diet, and exercise.
5. These foods are your best friends.
Certain classes of food chemicals can actively and powerfully lower a person's bad cholesterol. Two--soluble fiber and phytosterols--have so much science behind them that they've become part of standard medical prescriptions for treating high cholesterol. But dietitian Janet Brill, PhD, RD, author of Cholesterol Down, also recommends regularly eating almonds, ground flaxseed, apples, soy protein, and olive oil. Preliminary research suggests they all have cholesterol-lowering powers. "Each one works in a slightly different way," Brill says. "So together, you get a synergy that can dramatically lower cholesterol."
Almonds and olive oil are high in monounsaturated fats, which are thought to blend with LDL molecules in a way that speeds LDL's clearance from the blood by the liver. Flax is high in both soluble fiber, which lowers LDL by absorbing cholesterol from both food and bile inside the intestines, and omega-3 fatty acids, which studies show have anti-inflammatory effects. Other foods especially high in soluble fiber include oat bran, oatmeal, and apples. (Soluble fiber is different from insoluble fiber, the kind found in whole-grain bread and bran cereal. That's good for you, too, but it won't affect your cholesterol.) Soy may mimic natural estrogens in their LDL-clearing effects. Phytosterols are the plant version of animal sterols (a.k.a. cholesterol) and lower LDL by competing with it for absorption into the body. They're found in supplements or phytosterol-enhanced margarine such as Benecol.
You don't need any of these foods if your LDL is low, but experts still recommend them for everyone. What about steak, eggs, and cheese? They sure won't help your cholesterol, because they all contain a lot of it. But it's more important to focus on foods that lower your numbers rather than simply avoiding the bad stuff, experts say.
6. Good cholesterol may have a bad side.
The higher your HDL, the better, right? That's been the current thinking, due to HDL's protective effect. But here's a surprise you may have read about in some news reports: Studies are showing that HDL may actually have harmful proteins capable of boosting heart disease risks. A test to determine if your HDL has the harmful proteins may be available in a few years. In the meantime, if your HDL is lower than 60, it's still OK to raise it a little as long as you don't go overboard. How? Try getting a lot of omega-3s from fish or fish oil, exercising regularly, controlling your weight, and avoiding smoking.
7. Your heart loves long walks.
Walking 10 miles a week brings lasting improvements in your heart health, according to researchers at Duke University Medical Center. The funny thing is, if you jog those 10 miles, you won't get quite as much benefit. "Duration appears to be key," says Duke's Cris Slentz, PhD, an exercise physiologist. "Jogging or walking 10 miles both burned around 1,200 calories, but in our studies, one took about two hours and the other, three."
Longer stints of exercise, even moderate exercise, may burn more belly fat--the little rolls of skin near your navel and the fat deep inside your abdomen. The latter is linked to metabolic syndrome, a condition associated with a host of cardiovascular risk factors including low HDL, high blood pressure, and high triglycerides (a kind of blood fat that contributes to heart disease).
Should you aim for weight loss as well as long walks? If you're
overweight, absolutely. But understand that shedding a few pounds will
make only a small dent in your cholesterol. Canadian researchers
recently found that overweight women who lost about 25 pounds--no easy
task--saw their LDL drop about 10 percent and their HDL rise by the same
How Often Do I Need a Checkup?
Starting at age 19 and continuing until menopause, a cholesterol test once every five years is plenty--as long as your numbers fall in the healthy range:
HDL > 60
LDL < 100
Total cholesterol (HDL plus LDL) < 200.
But any time your numbers stray into unhealthy territory (and during and after menopause, when heart disease risk rises), get tested annually and work out an action plan with your doctor.Writer Jessica Snyder Sachs is the author of Good Germs, Bad Germs, out in paperback this fall.
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MRSA infects 94,000 Americans a year, and the superbug is no longer confined to hospitals. Here's what you need to know to protect yourself and your kids.
copyright Jessica Snyder Sachs, as first appeared in BEST LIFE magazine
It started one morning last June, when 14-year-old Max Yardley felt a little tenderness in his elbow. The arm looked fine, so Max's dad, Rockie, an explosives specialist with the Edmond, Oklahoma, police department, figured the problem was soreness left over from the lifeguard training Max had just completed. But that night, Max woke up his parents at 3 a.m. The pain had become excruciating.
"This is a kid who doesn't normally complain," says Yardley. "He'd been sick all of five days in his life." The Yardleys raced to the emergency room. Over the next 24 hours, Max's temperature soared to triple digits and his blood pressure plummeted. When doctors ran the usual laboratory tests, it came back positive for methicillin-resistant Staphylococcus aureus, or MRSA. A bacterial infection had infected the bone of Max's upper arm and was racing through his body, shredding up his lungs, liver, and spleen.
"One morning we had a perfectly healthy boy. Twenty-four hours later, the doctors were struggling to keep him alive long enough for the antibiotics to start working," recalls Yardley, who, as a former paramedic, understood enough about his son's vital signs to call the family's priest.
Unknown just 15 years ago, community MRSA (hospital MRSA's virulent sister) now accounts for more than half the serious staph infections showing up in the nation's emergency rooms. Some children's hospitals see it in more than 75 percent of the staph-infected children they treat.
"Once it arrives in a community, it just seems to take over," says Sheldon Kaplan, MD, chief of infectious diseases at Texas Children's Hospital, in Houston. Pediatric specialists fear that the superbug, which already accounts for 19,000 deaths in the United States each year, could soon become commonplace across the country. The vast majority of community MRSA cases are skin and soft-tissue infections, Dr. Kaplan explains.
But around 5 percent involve potentially deadly pneumonias and internal infections such as Max's. When this bug enters the bloodstream, it can cause severe and sometimes fatal disease, and many of those who survive bloodstream infections sustain severe organ damage, require limb amputation, or both. "A child's growing bones remain particularly vulnerable," says Dr. Kaplan, "because they are open to bacteria circulating in the bloodstream."
Max was one of the lucky ones. After a week on a respirator, he emerged without permanent organ damage. After another two weeks on intravenous antibiotics, he finally went home to complete his recovery and was symptom free after another seven weeks on antibiotics.
Each year, more and more kids aren't so fortunate. MRSA deaths among previously healthy kids began cropping up in the 1990s. "At first we assumed these children had some connection to a health-care setting in which MRSA infections had been confined," explains epidemiologist Jeffrey Hageman, a MRSA expert with the Centers for Disease Control and Prevention, "but it eventually became clear that something else was going on." Antibiotic use outside of hospitals may have bred strains of MRSA distinct from those in medical centers.
And although community MRSA isn't resistant to as many kinds of antibiotics as is hospital MRSA, what it lacks in multidrug resistance it appears to make up for in virulence. Medical experts are just working out how staph in general, and MRSA in particular, wreaks its damage. But new studies suggest that community MRSA strains have the ability to kill the kinds of immune cells that would normally eliminate such microbial invaders. This stubborn persistence, in turn, tends to trigger septic shock, a kind of immune-system meltdown in which body-wide inflammation leads to organ failure, massive blood clotting, and plummeting blood pressure.
Community MRSA has an aggressive tendency to enter through even the smallest of cuts and abrasions. For this reason, it often spreads in locker rooms and gyms, and between members of sports and dance teams, who have frequent skin contact with both other participants' skin and shared surfaces such as athletic equipment and benches, explains Hageman.
Ineed, if you have a child in school or day care, chances are you've received some version of the panic-but-don't-panic note, as in "Dear parents: A confirmed case of MRSA infection has been brought to our attention. Please be assured we are taking appropriate measures." Some schools go so far as to shut their doors for a massive, one-time disinfection--a move that may be as ineffectual as it is overdramatic.
A less overblown but diligent effort is key, say health experts. "Perhaps one of the biggest problems for parents, dads in particular, is deciding when to give your kid Tylenol and send him to bed and when to go straight to the emergency room," says Yardley. "For me, it was the urgency of Max's complaints that raised the red flag."
Here's what you need to know to protect your children from community MRSA:
1. Know When Risk is Greatest
Studies show some of the highest rates of MRSA in groups such as team athletes and those who have had a medical procedure or taken antibiotics within the past year. MRSA is what doctors call an "opportunistic pathogen," a microbe that takes advantage of breaches in the body's defenses. Young children are particularly susceptible because their immune systems aren't yet fully developed. "Staph. aureus can't be eradicated," explains MRSA expert Jeffrey Hageman, of the Centers for Disease Control and Prevention. "Overall, around one in a hundred Americans carries a resistant strain of this bug."
2. Avoid Unnecessary Antibiotics
MRSA infection rates are up to eight times higher among those who've taken antibiotics in the previous year. By eliminating the drug-susceptible competition, antibiotics promote the success of any microbe that can shrug off their effects. "Antibiotics tend to replace your body's protective bacteria with drug-resistant troublemakers," explains Tufts University's Stuart Levy, MD, author of The Antibiotic Paradox. When antibiotics are necessary, ask your doctor for the "narrowest spectrum" (most specifically targeted) antibiotics, which tend to be less disruptive of the body's good bacteria than are "broad spectrum" (big gun) antibiotics.
3. Wash Away the Bugs
"Teaching children good hygiene is the single most important thing you can do to protect them," says Hageman. Staph spreads primarily through skin-to-skin contact and frequently touched surfaces. Experts recommend frequent hand-washing with ordinary soap and water or, when that's not convenient, an alcohol-based hand gel. "Staph takes several hours to infect an abrasion," says Hageman, "so there's a window of time when it can be washed from the skin."
Drug-resistance experts such as Levy advise against using antibacterial soaps containing chemicals such as triclocarban and triclosan. They act like antibiotics and, in laboratory tests, promote the rise of drug-resistant bacteria.
4. Keep Exercise Areas Clean Encourage young athletes--or their coaches--to wipe down mats and sporting equipment with soap and water or bleach wipes between uses. Children can also use a personal towel or other barrier between their skin and shared exercise surfaces and equipment. Insist on daily disinfection of locker rooms and weight-room benches, wrestling mats, and other shared athletic equipment as well as the mats used by younger children for napping. The Environmental Protection Agency maintains a list of safe and effective MRSA disinfectants.
5. When in Doubt, Check It Out
MRSA infections don't always look scary. The skin may become red, swollen, and tender. An infected joint, bone, or muscle may look normal but feel painful. Sometimes symptoms include fever, nausea, or weakness, says Sheldon Kaplan, MD, of Texas Children's Hospital. That can make MRSA infection difficult to distinguish from muscle sprains or the flu.
6. Get a Flu Shot
When MRSA and the flu end up in the same body, the result can be life-threatening. "It's the perfect storm," says John Francis, MD, an infectious disease consultant at Yale University School of Medicine. Getting an annual flu shot may help protect against this deadly combination.
Jessica Snyder Sachs is the author of Good Germs, Bad Germs, out in paperback this fall.
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copyright Jessica Snyder Sachs, as first appeared in HEALTH magazine
Three months before she gave birth last year, Diana Simpson, a dental hygienist in Davison, Michigan, started coughing uncontrollably. The pain in her throat and chest was unbearable. "It brought me to tears," she remembers. Simpson's family doctor tested her for asthma, but she didn't have asthma. She had pertussis, a bacterial infection that usually goes by the name whooping cough because of its distinctive seal-like cough.
Most people are vaccinated against pertussis as kids. But here's a surprise: It's come roaring back since an all-time low in the 1970s, largely due to waning immunity in adults who received shots in early childhood. The Centers for Disease Control and Prevention (CDC) now recommends that all adults get a pertussis booster shot to strengthen their immunity, yet only 2 percent of adults have had their shots updated. Experts say that's just one of several vaccines you may need now. Here's the scoop.
The good news: If you get your regular tetanus-diptheria (Td) booster every 10 years, you won't need an extra jab for pertussis. Vaccine makers have added a pertussis component to that booster, so next time you're due for your Td booster request the Tdap. If you've lost track of your vaccines, ask your doc to contact your previous physicians. And there's no harm in getting the Tdap as long as two years have passed since your last Td booster. Better too soon than too late when a pertussis outbreak has hit your community.
Simpson was too late: She had passed the infection to her mother and her baby, too, landing the newborn in the hospital three weeks after he was born. That's when they all were diagnosed and received the antibiotic erythromycin to keep the infection from spreading further, though they all continued coughing for months. If pertussis isn't caught in the first few weeks, the infection may take three months to run its course. The greatest danger is to babies, who almost always catch it from unvaccinated adults. (The number of U.S. pertussis cases now ranks in the thousands each year, with deaths in the double digits, mostly due to related pneumonia.)
Simpson and her baby, along with her mother (and husband, too), eventually got the shot for future protection.
More than 90 percent of women in their childbearing years are immune to chicken pox because they had it as kids. The rest should be vaccinated before they try to get pregnant because catching the illness during pregnancy can lead to devastating birth defects. Once you get the vaccine (which was introduced in 1995), the CDC says you should delay trying to conceive for at least one month, due to the small risk that the fetus can get the virus from the vaccine. Chicken pox complications are much more frequent and severe in adults than children and can include life-threatening pneumonia and encephalitis (brain inflammation). And people who've had it are also at risk for shingles. Most insurers cover the chicken pox vaccine for adults.
If you've had chicken pox, you have a significant risk of developing shingles, a painful reawakening of the chicken pox virus. Worse, in nearly 50 percent of cases in adults in their 50s, shingles progresses to postherpetic neuralgia, an often agonizing form of nerve damage that can linger for years. (The risk increases with age.) But with the recent Food and Drug Administration (FDA) approval of the Zostavax vaccine, you can lower your risks dramatically. In a study of more than 38,000 adults over age 60, the vaccine cut the rate of shingles by over half and reduced the incidence of postherpetic neuralgia by two-thirds.
The vaccine was studied in and approved for people over the age of 60 because they have the highest rates of shingles, says William Schaffner, MD, head of preventive medicine at Vanderbilt University Medical Center. "The rates take off at age 50 and become more steep with each decade," he says. But around half of all shingles cases occur in younger adults.
Insurers won't currently pay for vaccination in people under 60, but that may change because studies in 50-and-overs are ongoing. Younger adults can pay out of pocket for this $150 to $200 shot. (Ask your doctor.) Researchers don't yet know whether the vaccine's protection will prove lifelong, though, so you may need a booster when you get older.
Vaccine: MMR booster
The measles-mumps-rubella (MMR) vaccine, a must for kids, is back in the adult-vaccine lineup, too. "Mumps is the problem," reports CDC epidemiologist Andrew Kroger, MD. The number of Americans who caught this viral disease jumped to 6,584 in 2006 from 300 or less in most years. A large mumps outbreak in the Midwest was responsible for most of these cases, and outbreaks continue in Canada and neighboring states such as Maine. The problem may be a spillover from countries like the United Kingdom and Japan, where lagging childhood immunization rates spurred a comeback.
Mumps can be painful and sometimes dangerous. There's the textbook swelling of salivary glands around the neck, but some women also suffer from inflammation of the ovaries. In rare instances, mumps can trigger life-threatening encephalitis.
The CDC encourages all adults to check their status: Do you know whether you were immunized or had the disease as a child? Those born before 1957 are presumed to have been infected or exposed, which provides lifelong immunity. The spottiest protection is among those born between 1957 and 1967, who are less likely to have had mumps or who may have received a less-effective vaccine. A single dose of the current MMR should bring your protection up to date, Kroger says, and it may be covered by your insurance.
Going on a cruise or an organized tour? Consider getting a flu shot, says Schaffner, who reports that influenza outbreaks frequently occur on cruise ships, even during summer voyages to northern destinations like Alaska. "Whenever people are jammed together, influenza is a risk," he explains.
In addition, visitors to Asia should talk to their doctors about vaccine protection against typhoid and Japanese encephalitis. Visitors to the "meningitis belt" of central Africa should get a meningococcal vaccine. And yellow fever vaccines are important for travelers to much of South America and parts of Africa.
Vaccine: Recombivax HB or Engerix-B
Both vaccines protect against the hepatitis B virus, which is spread through sexual contact or contaminated needles and blood. An infection can lead to dangerous liver disease. Each year, more than 78,000 Americans become infected and about 5,000 die of associated liver diseases, including cancer, yet few know that the CDC recommends the vaccine for all sexually active people who are not in long-term relationships.
Vaccine: Influenza shot or FluMist nasal vaccine
A dangerous bug known as methicillin-resistant Staph. aureus (MRSA) may aggressively attack flu-weakened lungs, according to William Schaffner, MD, head of preventive medicine at Vanderbilt University Medical Center. MRSA was previously confined to hospitals but is spreading into communities nationwide. The link is unclear, but there may be a connection in the way that flu weakens the immune system and MRSA attacks it. MRSA is often marked by nasty skin infections. The strains contracted outside the hospital are now associated with some 13,500 deaths in the United States each year, many involving flu sufferers. "If you need further motivation to get a flu shot," Schaffner says, "there it is."
Jessica Snyder Sachs is the author, most recently, of Good Germs, Bad Germs.
Copyright Jessica Snyder Sachs, as first appeared in Discover magazine
Insects can help solve murders but their testimony is being attacked in the courts. Pigs in stockings may help make the bugs respectable.
In the cow town of Stroud, Oklahoma, no one thinks twice about a junk pile alongside a neighbor's driveway. But people paid attention to the pile by Aureliano Cisneros's house, thanks to the thick swarm of shiny, fat flies and a ripening stench. On August 8, 1994, police discovered within that junk pile the decaying, maggot-packed body of Cisneros himself. Apparently, after being stabbed in the chest and neck, he had collapsed in front of his house; a short drag mark in the lawn suggested that someone then tried to move the 220-pound corpse before hiding it beneath the heap of dresser drawers, suitcases, and blankets.
Suspicion quickly fell on Cisneros's wife, Linda Howell. The previous Thursday night, August 4, witnesses saw the couple storm out of a local bar, with Howell saying, "You son of a bitch, I'm gonna kill you!" When investigators came to Howell's door, though, she said she'd been wondering where Cisneros was. Yes, they'd argued Thursday night, she acknowledged, but they'd made up before morning. She hadn't seen her husband for two days, since the evening of Saturday, August 6, when he left home to join some buddies.
The police didn't buy her story and arrested her for the murder of her husband. Yet when Jackie Johnson, a deputy inspector at the Oklahoma State Bureau of Investigation, looked over the forensic evidence, she wasn't very confident about the case. None of the reports gave her anything to refute Howell's claim that Cisneros was still alive two days after their public brawl.
Ironically, it was Howell's defense attorney, Frank Muret, who led Johnson to the evidence she needed. When she was handing over the forensic reports to Muret, he asked if they had looked at the maggots on the corpse. If they had, he was entitled to know what they'd found. As soon as Muret walked out the door, Johnson picked up her phone. Two calls later, she had located Neal Haskell, one of North America's most unusual private investigators. Haskell is a forensic entomologist--a scientist trained in gleaning criminal information from insects. He is, in fact, the world's only full-time forensic entomologist, though he counts as his colleagues a dozen or so other researchers who pursue forensics as a sideline. Haskell earned his Ph.D. from Purdue back in 1993. Now he crisscrosses the continent in a dusty white van with the Indiana license plate MAGGOT, consulting with the police in homicide cases and conducting research of his own.
Johnson asked Haskell if he could testify
about Cisneros's time of death based on photographs, case reports, and a few
vials of maggots--that is, fly larvae--collected from the body. "No
problem," Haskell replied.
Haskell identified the larvae as belonging to two common flies: the black blowfly and the secondary screwworm. He then determined that these maggots were in their third developmental stage, or instar, the last before they would crawl away from the corpse to pupate and mature into adult flies. Since temperature influences the pace at which flies develop, he consulted the temperature records from the nearest weather stations, then calculated that the maggots had come from eggs laid on the body 72 to 96 hours before discovery. In other words, Cisneros could have died no later than the morning of August 5--a day earlier than Howell claimed she had last seen her husband alive.
Howell's lawyer did not exactly cave in when faced with the scientific evidence. Instead he tried to have it suppressed. During the pretrial hearings, Muret pointed out that much of the research on how blowflies develop has been conducted not on human cadavers but on dead pigs or cows' livers, and that, he argued, makes the findings inapplicable to homicides. Haskell replied that, as a matter of fact, he was preparing to publish some of his own research on human corpses, done in Tennessee. The results were consistent with nonhuman experiments.
Next Muret objected to Haskell's reliance on research done outside Oklahoma. He questioned whether developmental charts created in Tennessee are accurate enough for flies in, say, Oklahoma. This leap of faith--that blowflies in different regions grow at the same rate--is generally accepted by entomologists but remains unproved. "I've collected maggots at hundreds of workshops from one end of this country to the other," Haskell countered gruffly. "I've never seen significant variation in their growth rates outside of that determined by temperature."
Which led Muret to his next and final objection. Haskell had relied on weather readings that had been recorded miles away from Cisneros's house. Since temperature is a powerful influence on how quickly larvae grow, police should have recorded the temperature at the scene of the crime. Pulling out a field manual that Haskell himself had published, the defense attorney pounced on a passage detailing the proper procedure for determining temperature at the scene of a murder. "Did the police at the scene take ambient air temperature readings at one-foot and four-foot heights in close proximity to the body?" he asked, repeating Haskell's own instructions. "Did they take ground surface temperatures, body surface temperatures, and maggot-mass temperatures?"
Haskell granted that they had not. In making his calculations, he had used a composite of temperatures taken at weather stations miles from Stroud. Muret objected, calling the calculations guesswork, and urged the judge to rule Haskell's testimony inadmissible.
"Fortunately," recalls Haskell, "that judge was also a rancher, a no-nonsense kind of guy. When he finally made his ruling, he basically said, `When it's hot in Oklahoma City, it's hot in Stroud.'"
The judge admitted Haskell's testimony. Soon afterward Howell accepted a plea bargain.
Disputes like these over the courtroom legitimacy of entomological evidence are becoming more frequent and more pointed. In the coming years, says forensic anthropologist Bill Bass, of the University of Tennessee, such challenges will largely determine whether forensic entomology can take its place alongside such established practices as DNA fingerprinting, fiber analysis, and ballistics. Even his own science, says Bass, the identification of victims from recovered bones, "is ten years or so ahead of entomology in terms of acceptance in the courtroom."
Some forensic entomologists welcome this trial by fire. It's worth the struggle, they say, because their science offers the most reliable way of determining the time of death at a crime scene, short of an eyewitness. "Medical examiners have never been comfortable determining time of death," admits Amy Fantaskey, a pathologist with the University of Hawaii Medical School. In the first 72 hours, pathologists can make crude estimates based on rigor mortis, blood-pooling patterns, and body temperature. "But these are iffy determinations, more art than science," says Fantaskey. And beyond 72 hours, as the body cools, blood-pooling patterns fade, and rigor mortis melts away, these methods become useless.
This is exactly why some judges have been so receptive to forensic entomology. Insects populate the human corpse--or any carcass--in predictable waves over the course of weeks. The first to arrive are the husky bombardiers known as blowflies, or bottle flies, distinguished by their metallic sheen. Though cold weather and closed doors can delay their arrival, in warm weather they materialize within minutes of a body hitting open ground. "Just leave a steak uncovered by the barbecue," notes entomologist Gail Anderson of Simon Fraser University in Burnaby, British Columbia. "You'll see how fast they pull in."
Entomologists suspect that the first blowflies to find a corpse lay down chemical signals that draw kin from miles around. Within hours, the body crawls with flies. The females pack their eggs, like a paste of Parmesan cheese, around wounds and orifices such as eyes, nose, and mouth. Eggs typically hatch 12 to 72 hours later, depending on the temperature and the species of blowfly. The squirming maggots begin life the size of a pen nib. As they feed, they secrete enzymes that enable them to slice through soft tissue like butter. As their numbers swell into the tens of thousands, they move through the corpse in roiling, crackling packs, all of them growing quickly through their instars in a matter of days or weeks.
After reaching a fat third instar, the satiated larvae--about half an inch long--crawl away from the corpse and bury themselves in soil or debris. If they are in a house, they will seek dark crevices such as the folds of bedsheets. Their larval skins shrink and harden into pupa cases. The adults emerge 6 to 14 days later. Unable to fly for several hours, they skitter around the corpse like hyperactive spiders, waiting for their wings to expand.
The development of various species of blowflies has been so well documented that blowflies have become the most reliable postmortem insect clock. Once these flies depart, it becomes harder to determine time of death with precision. An entomologist must then knit together the arrival and departure of several other kinds of insects that visit the body in a more or less orderly succession.
Hawaii entomologist Lee Goff has made good use of this puzzle-piece approach. In 1996 he handled a particularly grisly case in which the decomposed corpse of a Marine--with an execution-style bullet wound--was found in a rain forest just off the Old Pali Highway on Oahu. By the time Goff arrived (in his usual mariner, aboard a Harley-Davidson, with his collecting bottles and a collapsible butterfly net tucked into a side pouch), most of the blowflies had already come and gone, but a host of other insects were still busy with the corpse. "We had clerid beetles and hide beetles, both of which like their bodies slightly dried. I also found larvae of a rove beetle--it arrives early, but you don't see its larvae until a couple weeks into decomposition. Then I had hairy maggot blowfly; this was neat because it takes at least 17 days to emerge, and all I had were empty puparia." Goff also found cheese skippers, flies that arrive no later than a week after death. "The trick to cheese skippers," says Goff, "is that after a month, they pop off the corpse to pupate in the soil. So the fact that I find larvae means we're under 34 days." Finally Goff found soldier flies. "This one's pretty definitive for my time estimate because they let the body age for about 20 days before coming in. And the ones I collected were fifth instars, between 9 and 11 days old."
Goff thus placed time of death at 29 to 31 days before the body's discovery. Military police confronted two Marines seen with the victim 30 days earlier, and they confessed.
Part of what makes the method work so well for Goff, though, is Hawaii's isolation and its relatively limited number of insect species. Experts on the mainland find it harder to make such definitive analyses. They often encounter dozens of different cadaver-loving insects, only the most common of which have been studied adequately. "It's not unusual to find ourselves estimating the developmental time of a lesser-known insect based on that of a close relative that's been better studied," admits forensic entomologist Robert Hall of the University of Missouri. This kind of deduction is an easy target for legal attack. "On cross-examination, a good lawyer will say, `So, Dr. Hall, what you're telling us is you're guessing.'"
For forensic entomologists to answer such challenges requires thousands of hours of more research and legions of graduate students, but these are hard to come by in their underfunded field. A noticeable exception has been a program set up by Gail Anderson of Simon Fraser University, largely funded by the Canadian Police Research Center. Anderson's students camp out across the rugged landscape of British Columbia year-round, each baby-sitting the carcasses of several dozen pigs. To simulate real-life homicides, some of the victims lie buried in soil or partially submerged in streams or lakes.
In 1995, Anderson's students began clothing some of their pigs. "In Canada, at least, most of our murder victims are dressed," she explains. "We needed to document whether this altered insect behavior." The research raised eyebrows across North America when a school newspaper intercepted a grad student's e-mail request for used panties and bras.
Wire services quickly spread the story:
WANTED: PIG UNDERWEAR.
"I was sure I was going to get kicked out of the program for that one," recalls Leigh Dillon, now a coroner. "But certain things you can't find at Goodwill." In fact, by studying pigs in underwear, the entomologists learned some important things--that clothing, for instance, helps conserve moisture in a corpse, so that it will remain attractive to blowflies longer than if it is naked, and that maggots tend to eat the skin when a body is clothed but not if it is unclothed.
Then there are greater barriers between a fly and its host, which pose an even greater puzzle for forensic entomologists. It's one thing to say that blowflies will find an exposed corpse within minutes. But what if the body lies indoors, in a car mink, or wrapped in garbage bags? Because of such uncertainties, entomologists are only willing to offer estimates of the minimum time elapsed since a death, leaving open the possibility that the flies were delayed in reaching the body. Haskell will add 48 to 72 hours to death estimates for bodies found in closed spaces. "If a fly hasn't found the body by then, it's not going to," he says.
A better approach is to replicate the murder, says Goff, who recently did just that by wrapping a pig carcass in blankets and dropping it in his backyard. His impromptu experiment gave the court a convincing postmortem interval for a woman found in similar circumstances. "But things got a little twitchy with my neighbors," he admits.
Forensic entomologists also know that their science will be reliable only if police and medical examiners recognize the value of the bugs they encounter. Lamar Meek of Louisiana State University grumbles about one case in which the only specimen he was given was a photograph of a mass of eggs on a victim's ear. Since the body was indoors and had been found in the late morning, he testified that for the blowflies to have had enough time to find the corpse, the murder must have happened at least a day earlier--and possibly a day and a half earlier, on the evening the suspect admitted burglarizing the home. In response, the defense made their own estimate from the photograph of how old the eggs were, which they claimed pointed to the murder's taking place the following night. Meek knew their reasoning was poor but couldn't categorically refute it because he didn't have the actual eggs to analyze. "I couldn't disprove it with a picture."
Researchers like Meek wish that a forensic entomologist could be part of every crime-scene investigation, but with so few experts in the country, the next-best approach is for homicide investigators to be trained to do the necessary fieldwork. Some police departments are beginning to send their officers to "police entomology" courses held at universities around the country. Among them is the annual spring workshop directed by K. C. Kim at Penn State. This year found Kim, Haskell, and grad student David Skipper leading a line of detectives, pathologists, and coroners through the woods behind the Penn State campus.
"In the seventies or eighties, my superiors would have laughed at this," said Pennsylvania state trooper Jim Shubzda as he traipsed through the forest. "Maggots were just something we pushed aside to look at other Stuff."
As the group approached a forested area, the breeze grew perfumed with a sweet, skunklike smell. The more jaded in the group grinned at the familiar scent. "We've got some stinkers," someone cracked. Pushing aside branches, the group followed a deer trail leading to Joe Pig 1, 2, and 3. Spaced about 100 feet from each other, the victims lay in three different stages of maggot-infested decay. (The pigs had been killed by injection before being brought to the forest.)
Pig 1 was especially ripe that morning. The group's arrival dispersed a thick cloud of chunky black flies. Not so easily disturbed was a swarm of plump maggots churning inside an open wound on its flank. Masses of smaller maggots packed themselves into the pig's mouth and nostrils. Dusty patches of empty egg cases still clung to the wiry hairs around the cavities.
"Listen," whispered Skipper. Bending close to the open flank wound, students could catch the crackling of feeding maggots. Then a cascade of maggots tumbled out, pouring onto the ground. "Periodically they have to come up for air to cool off," Skipper explained. "A big maggot mass can generate a lot of heat."
The class broke into three groups, each assigned to a pig whose time of death they had to determine based on the insect evidence. "I want a nice sample of maggots from each wound and orifice," Skipper told his students. "Then get me at least one of everything else you can find." He supplied everyone with alcohol vials for preserved specimens and "maggot motels" (icecream cups with beef liver) for rearing live ones.
"All these things we're teaching you are to keep us from getting beat up in court," added Haskell. He launched into a diatribe on botched collections. "Once all we had were some squished maggots on a bloody blouse. I mean, for Christ's sake, they'd been stuffed in a paper bag and left in an evidence locker for over a year!"
Haskell reached for a long-handled butterfly net and then waited for a half-dozen blowflies to settle on Joe Pig 1's rump. He skimmed the net gracefully over the carcass and then gave the net a twist to trap several flies. After transferring the specimens into a vial, he handed the net to a pathologist to catch some flies of her own. She whacked the pig on the rump and came away empty.
Meanwhile, a monarch butterfly drifted down from the trees to settle on the white hairs of a pink ear on Pig 3. A student reluctantly poised himself to capture it, but Skipper called out, "Not of forensic value."
Later, in the lab, the students examined their maggots under microscopes. "Identifying species is the entomologist's job, not yours," Kim said, "but we want you to see what we look for so you can appreciate the importance of proper collection."
Specifically, the entomologist distinguishes different species of blowfly maggots by features such as the arrangement of the hooks lining their mouth and structures around their anus known as spiracles. Resembling a pair of sand dollars, the spiracles serve as breathing organs when the maggots bury their heads in putrefying flesh. The spiracles also reveal a maggot's stage of development--it starts life with one slit on each spiracle, and with each instar it adds another slit.
As forensic entomologists struggle to make determining time of death court-proof, recent work has begun to push the science's powers in new directions. At the FBI's National Center for the Analysis of Violent Crime in Quantico, Virginia, entomologist Wayne Lord has figured out how to use maggots to help medical examiners detect drugs or poisons in their hosts' bodies. "We've taken the you-are-what-you-eat scenario to its limit," says Lord. Recently he was asked to help determine the cause of death of a nearly skeletonized male body that had been found by hikers in a wooded area of Connecticut. He plucked blowfly larvae from the clothing and body cavities, made a puree of them, and from it detected high levels of cocaine. Combining Lord's results with the victim's case history, the medical examiner concluded that the man had died of an overdose.
In another case, Lord was faced with even less evidence: the mummified remains of a middle-aged woman who had died in her New England home two and a half years earlier. (Her death had gone unnoticed until foreclosure agents entered her house.) Instead of actual maggots or beetles, Lord could collect only empty blowfly pupae and beetle droppings. But even with these scant materials, he was able to detect an antidepressant. The woman's death was ruled a fatal overdose.
Most remarkable of all, Lord is now perfecting a method for tracing DNA found in bloodsucking insects to the humans on which they have fed. "It's only a matter of time before we put this research to work in an actual case," Lord says. "Most likely it will involve a rape and murder, in which the suspect's blood is retrieved from crab lice left on the victim." At the moment, Lord is still determining the feasibility of this approach, but he is confident it will work. If he's right, then someday one more previously mute witness will speak for the dead.
JESSlCA SNYDER SACHS ("A Maggot for the Prosecution," page 102), former editor of, Science Digest, is a science writer from the Atlanta area. "During the course of this assignment I inadvertently sickened and completely alienated the film processor at our local photo shop," she says. "I had a roll of film that was half family vacation pies, half maggot-infested body pies. My husband, not knowing, took them in to be developed without warning her. Boy, did she tell him off when he picked them up!" Sachs is now the proud owner of a black T-shirt that reads ENTOMOLOGY AND DEATH.
Jessica Snyder Sachs, a regular contributor
to National Wildlife magazine, is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Hill&Wang/FSG) and Corpse: Nature, Forensics, and the Struggle to Pinpoint Time of Death (Perseus/Basic Books).
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Understanding plains zebra society could prove crucial to conserving Africa's tropical grasslands
Copyright Jessica Snyder Sachs, as first appeared in National Wildlife magazine
THE DRY SEASON grips the highland savanna of eastern Africa between late May and early June. As the relentless sun drives the last bit of moisture from the soil, the verdant highlands shrivel to yellow and brown. Herds of antelope, gazelle, wildebeest, elephant and buffalo gather by the hundreds of thousands, chafing to begin their annual migration to the lowlands to find water. Lions, hyenas and other predators likewise ready themselves to follow their prey on the seasonal journey.
But none can leave the depleted highlands until the plains zebra departs--and readies lowland grasses for the grazers that follow. "They start the whole grazing succession," says Princeton University ecologist Daniel Rubenstein, who has been studying the species for the past 15 years. Because zebras have an unusual hindgut digestive system rich in fermenting microbes, they can gorge on the low-quality coarse straw available at the start of the rainy season. Buried beneath this sunlight-blocking thatch lies the tender new growth upon which all other grazers depend. This means that from the vast, acacia-dotted savannas of the Serengeti, south through Zambia's scrubby woodlands and the treeless veldt of South Africa, the plains zebra plays an unmatched role in maintaining some of the most biologically diverse habitat on the planet.
Consequently, the long-term conservation of Africa's tropical grasslands relies on the wise stewardship of this linchpin species, says Rubenstein. In partnership with the African Wildlife Foundation and Earthwatch Institute, he currently heads a broad-based project aimed at integrating zebra conservation with the rapid growth of agriculture, livestock and game-ranching industries in eastern Africa.
To the tourist on safari, the plains zebra certainly looks to be thriving. Indeed, where these zebras still occur, their inimitable stripes dominate the landscape, with a population of nearly 665,000, dwarfing that of its two gravely endangered cousins--the Grevy's zebra of Kenya and the mountain zebra of Namibia and South Africa.
"But if you actually look at the details," says Rubenstein, "you see that the plains zebra has been extirpated from much of its historic range." Today, 70 percent of its population concentrates in just two countries, Kenya and Tanzania. Ecotourism dollars have enabled these nations to protect large swaths of lowland zebra habitat inside national parks. But just outside park borders, farms and ranches have sprung up to block many of the age-old migration routes that zebras need to cross between dry season refuges and lusher uplands. Though the lengths of these migration routes vary widely, many populations travel hundreds of miles a year.
In Tanzania, for example,"there used to be nine migratory routes out of Tarangire National Park," says Rubenstein. "Now there are only two or three left, all on privately owned land." Because of the low quality of their grasses, dry-season refuges such as Tarangire can't support large populations of zebras unless the animals can fatten up in adjacent highlands during the wet season.
How this changing landscape will affect the plains zebra is unknown. But what is certain, given Rubenstein's studies, is that human activities are affecting the species' unique multilayered social structure.
At the core of plains zebra society is a breeding group, or harem, with a single breeding stallion, up to six mares and their young. Rubenstein has discovered that although the stallion defends his harem from danger and harassment, the mares generally call the shots. "The males that let their females do what they want--organize behind the scenes and choose the kind of grazing they want--those are the stallions that get the most females," he says.
As with many social mammals, female plains zebras form strong, long-term bonds with one another and stay together even after the death of a stallion. What's unusual is that the females in a zebra harem are not related. And unlike many other large mammals--such as lionesses and female elephants, which form alliances with sisters and daughters--plains zebra mares cast out all of their offspring. "In fact, it's usually the young females who get the message first and take a hike," says Rubenstein. In her second year, a maturing filly goes in search of a young stallion. A young male leaves by his third year, either to join a bachelor group or begin recruiting his own harem.
Adding more complexity, stallions and their harems often band together to form a much larger, loose-knit herd of several hundred, where the females freely comingle. Yet the stallions generally resist pilfering each other's mares. The purpose behind these superherds appears to be defense against raiding parties of bachelor males. "A single stallion set upon by a large group of bachelors has little chance of defending his females. As he barrels into the mob, taking on five or six of the marauders, the others just stream around him and head for the females," says Rubenstein. By contrast, a coalition of stallions can present a united front to keep the interlopers at bay. Rubenstein has observed that the more bachelors in a given area, the larger the combined-harem herds.
This elaborate social system complicates the task of conserving and managing the plains zebra. Many zebras live on private game ranches, where hunters target established stallions--the male's brighter coat makes for the most desirable trophy and the "homebody" stallions tend to be easier to find than the farther-ranging, vagabond bachelors. But increasing the proportion of bachelors causes surviving stallions and mares to band together even more, producing an unnatural herd size. "It's creating a whole new population structure," says Rubenstein, "It's not clear whether this is natural or sustainable, or what it might mean for the future."
More clear-cut is the impact that stallion hunting has on the zebra birth rate. Remove a harem's stallion and the fertility of the surviving mares drops dramatically for at least two years while young and inexperienced bachelors vie for control. "From a game management point of view, that means fewer babies," says Rubenstein, "a fact that has to be taken into consideration when setting hunting quotas if zebra populations are going to remain self-sustaining."
That said, wild populations as large as the plains zebra's can adapt to new pressures. But only if they have enough space. "Free run is the issue," says Rubenstein. "The zebras can take care of themselves."
Jessica Snyder Sachs, a regular contributor
to National Wildlife magazine, is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Hill&Wang/FSG) and Corpse: Nature, Forensics, and the Struggle to Pinpoint Time of Death (Perseus/Basic Books).
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Copyright Jessica Snyder Sachs, as first published in Popular Science
Nothing in American
police work is more controversial than racial profiling. Minorities are
targeted for small offenses in the hope of uncovering bigger crimes, and the
practice has generated successful lawsuits by the ACLU and pledges from state
governments and law enforcement agencies to clean up their discriminatory acts.
Add to this charged atmosphere the prospect of a DNA-race angle. By now most Americans know that when criminals leave traces of themselves--blood, semen, hair, a scrape of skin under a victim's fingernails--at crime scenes, they leave a unique genetic fingerprint that can establish their presence at the scene with great certainty. Less known but more controversial is that DNA traces also leave clues about ancestry and appearance, clues that, as genetic science matures, might be used to generate a sort of police sketch.
Racial differences constitute small notes within the great opus of the human genetic code, but the very fact that genetic markers linked to ethnic origin are, in a sense, cosmetic--that is, they affect outward appearance--makes them potentially useful in the hunt for criminals. Is a suspect of fair Celtic stock or of darker African origin? His or her DNA may tell. Such information could prove far more useful to street-pounding cops than notoriously unreliable eyewitness reports. But unless the science proves reliable, there is risk here: The use of DNA markers could confer authority on police searches--isn't genetic information more reliable than even fingerprints?--that, in the area of racial markers and appearance, it may not deserve.
Until recently, genetic markers have not been used in manhunts, but that changed earlier this year when a private gene lab concluded that an unknown serial killer was a medium-to-dark-skinned black, not the white man that police had been focused on. The lab, it turned out, was correct, and although its conclusion did not directly lead to the arrest of the suspect, it advanced the case for supporters of the DNA sketch idea.
In 1997, when members of the national DNA Advisory Board officially selected the gene markers for DNA evidence matching, they could have included a few markers associated with ancestral geographic origins (European, East Asian, sub-Saharan African)--which are a good indication of race and ethnicity. "We deliberately chose not to do so," says Ranajit Chakraborty, director of the University of Cincinnati's Center for Genome Information. Chakraborty says the board skirted the racial-marker issue in part because of the political minefield it represented. Thus today's standard American DNA fingerprint, with its battery of 15 gene markers (two were recently added to the standard 13), is a sort of bar code identifier that is fine for matching two DNA samples but offers no hints about the human package from which a crime-scene DNA sample is derived.
Not that DNA hasn't already been quietly used for ethnic identification. Following the 9/11 terrorist attacks, Chakraborty acceded to the request of a family whose son had been a passenger on United Flight 93 (the thwarted terrorist mission brought down in Pennsylvania). "We had a specimen that consisted of at least two individuals' remains, one of which was their son's," he explains. "The family was reluctant to bury it with his other body parts if it contained any remains that might belong to a hijacker." Chakraborty determined, with 95 percent certainty, that the unidentified tissue did not belong to anyone of Middle Eastern ancestry.
"We may not be able to tell German from French," says Chakraborty, "but we can place individuals in major continental groups." In turn, within each of these groups, certain types of hair texture, eye and skin color, and other facial features predominate. Such information could prove useful in an investigation, admits Chakraborty. "But (it) should not be interpreted that you can say with 100 percent accuracy that a person will have, say, brown eyes."
Because geneticists have largely kept mum about ethnic markers, it proved something of a shock when DNAPrint Genomics concluded last March that a Louisiana serial killer's "biogeographical ancestry" was 85 percent sub-Saharan African and 15 percent Native American. At the time, the police were on an altogether different track: They had been seeking a white man who had been seen lurking in the neighborhood of one of the crime scenes.
"Basically, the phone line went
silent," says Tony Frudakis, research director at DNAPrint, describing the conference call in which he revealed the lab's results to police investigators. They were dubious, Frudakis says, and asked to see DNAPrint's analyses of 20 other DNA samples of known individuals they'd sent along with the killer's sample to test the lab's reliability. "We got them all right," Frudakis says.
The investigators were convinced enough to expand their search to include African-Americans, then had a break in the case due to an unrelated incident. Derrick Todd Lee, called in for questioning about two unrelated killings, voluntarily gave a DNA sample, which police say matched DNA from the serial murders. Arrested on May 27 and now awaiting trial, Lee is African-American.
A basic ancestry profile may be just the beginning for the
DNA-based police sketch, boosters say. "To be honest, most of us are
mongrels," says Frudakis. "We reside somewhere along a continuum
rather than as members of physically distinct groups." He says DNAPrint is
developing genomic tests to detect more specific physical traits, and it hopes
to have the first such test--Retinome, for eye color--ready for market by the
end of 2003. "After that, give us another year for hair color," he
says. The latter is a particularly bold boast, since not much is known about
hair color markers beyond one associated with red hair.
DNAPrint is not the first to claim progress toward a gene-based police sketch. In the late 1990s, Britain's Forensic Science Service trumpeted the development of something called a DNA photofit. Emboldened by the identification of the gene marker for the "Celtic look" (fair skin and red hair), it poured money into an ambitious project at University College London. Scientists scanned the faces of hundreds of volunteers in an attempt to correlate digitized facial geometry with genetic markers.
The approach made intuitive sense, and it would have closely paralleled the anthropometric tricks used by police sketch artists, who build their drawings around a witness's best recollections of certain landmark geometries, such
as nose height and width, eye shape and the distance across the broadest part of the face.
The Forensic Science Service had faith that the University College team could deliver in a couple of years, says team member Alf Linney, a medical imaging expert at University College London. But the connection between genes and facial appearance proved too complex for the London scientists, and the project was suspended in 2000.
"We may never be able to fully reconstruct a suspect's face from genes alone," says Mark Benecke, one of Germany's most respected forensic biologists. "Genes coordinate the whole thing, but events during development and illnesses or malnutrition during childhood greatly influence facial symmetry."
As every high school biology student learns, genotype plus
environment equals phenotype--the physical expression of our genes. All of
which Frudakis concedes. Still, he argues that the sophistication of new
"high-throughput" computer analysis of genetic information greatly
expands the layers of genetic clues that can go into a DNA-based best guess
about a person's physical appearance.
"We're using neural networks and sophisticated pattern detection methodology to systematically determine genetic sequences over the whole genome for thousands of people," Frudakis says. "So when we're searching for genes associated with hair color, in essence we're doing a grid search. It's a treasure hunt in which we systematically determine, OK, the treasure isn't here, let's search the next grid." This contrasts, he says, with gene searches of just a few years ago, which were much more hit-and-miss.
Critics fear that the DNA sketch concept opens the door to biased, unscientific racial profiling based on unproven gene markers for behavior, including criminal behavior. "The temptation will be to run DNA data through computers to conclude, for example, that you can identify markers for, say, sexual offenders," warns sociologist Troy Duster, author of Backdoor to Eugenics and a consultant to the National Human Genome Research Institute. Imagine such a data crunch based on the DNA of convicted criminals, given the preponderance of black and Hispanic men in American prisons. "It would be like going to the NFL and concluding that the DNA marker for sickle-cell anemia (associated with African ancestry) makes you a good football player."
Despite such objections, forensic biologists like Benecke predict that the accuracy of DNA-based descriptions will edge past that of eyewitness accounts within 15 years, barring legal roadblocks. Germany currently outlaws the disclosure of DNA-gleaned information, except in medical situations with a patient's consent. "Technically, we're not even supposed to notice if there's a Y (male) chromosome," says Benecke. "But how can it be an invasion of privacy if we're only looking at things that can be seen from the outside?"
Unencumbered by such privacy laws, U.S. forensic labs already have nearly everything they need to develop their own "genetic witnesses." Given the time and money, they will continue with the genomic sifting and sorting. Frudakis makes this bold prediction: "A few years from now, we're going to have figured out so many traits that a criminal might as well leave his driver's license at the scene of the crime."
Jessica Snyder Sachs, a regular contributor to Popular Science, is the author of Good Germs, Bad Germs: Health and Survival in a Bacterial World (Hill&Wang/FSG) and Corpse: Nature, Forensics, and the Struggle to Pinpoint Time of Death (Perseus/Basic Books).
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