Zoobiquity

  McNamara, a veterinarian and the zoo’s head pathologist, did two things right away. As a responsible employee, she called New York State wildlife officials to alert them to the alarming appearance of a deadly disease in the Bronx.

  But McNamara, a no-nonsense Queens native with a doctorate from Cornell and years of experience analyzing tissues under a microscope, knew a thing or two about bird diseases. With a maverick streak and a love of a good medical mystery, she began her own investigation. Peering at magnified slides late into the night, surrounded by jars of preserved amphibians and exotic reptile fungi, McNamara searched for clues to the mystery of what was killing her birds. One thing was obvious. The killer was swift and ruthless—frying the birds’ brains and ravaging other organs. They’d died of massive brain hemorrhages and heart damage. This pointed overwhelmingly to encephalitis—inflammation of the brain—caused by a virus. But which virus?

  McNamara knew she had three prime suspects: the viruses that cause Newcastle disease, avian influenza, and eastern equine encephalitis (EEE), all of which notoriously attack birds. With the clock ticking, McNamara began a process of elimination. Newcastle disease and avian flu are highly contagious. Spreading from animal to animal, they can wipe out adjacent flocks in no time. But they couldn’t be the culprit: the zoo’s exotic flamingos and eagles were dying, yet the chickens and turkeys in the children’s petting zoo were fine. McNamara crossed Newcastle and avian flu off the list. That left EEE. But, McNamara realized, the zoo’s emus weren’t sick. Healthy emus would seem to rule out EEE; the large, ostrichlike birds are particularly vulnerable to this virus and would certainly be showing signs of illness. With three strokes, McNamara had reduced her lineup of suspects to zero.

  It had to be a different pathogen, one that didn’t spread through bird-to-bird contact. That’s when McNamara thought: mosquitoes. The petting zoo closed before sundown and opened well after sunrise. The chickens and turkeys were housed safely indoors at dawn and dusk, the prime mosquito feeding times. However, the exotic birds that were dying—the flamingos and cormorants and owls—were housed outside around the clock. This was not a comforting realization. If mosquitoes were indeed spreading this contagion, whatever it was, the birds weren’t the only animals at risk. Any warm-blooded creature that provided mosquito meals—like the zoo’s rhinos, zebras, and giraffes—was in danger. So, too, McNamara realized grimly, were New York–area human beings.

  This was late August. Just a week or so before, emergency room doctors around New York had started tracking a mysterious illness cropping up in elderly people. It appeared to be neurological: patients were presenting with high fevers, weakness, and confusion. Some had signs of swollen brains—encephalitis. When the cluster of sick people reached four, an infectious disease specialist at a Queens hospital raised the alarm, and the Centers for Disease Control and Prevention (CDC) in Atlanta sent a team of epidemiologists to investigate. Because encephalitis was present, the CDC, too, was thinking, “Mosquito vector.” As one of the researchers put it, “If you see encephalitis in the later summer, you have to think about viruses spread by mosquitoes.” It had been a perfect year for the insect bloodsuckers. A long, dry spring followed by lots of rain and high humidity had created breeding conditions ideal for a population explosion.

  After a few days and some tests on the spinal fluid of the sick people, CDC officials triumphantly announced that they had solved the mystery. It was St. Louis encephalitis (SLE). This brain-attacking disease leaves its victims, especially the elderly, with outcomes ranging from bad fever and neck stiffness to death. It has no vaccine, and while reasonably common throughout the South and the Midwest, it hadn’t been seen on the East Coast since the 1970s. New York mayor Rudy Giuliani quickly rolled out a $6 million mosquito-abatement plan that included free insect repellant, reams of informational brochures, and a helicopter that sprayed malathion, a potent insecticide, over the city and its alarmed inhabitants.

  That might have been the end of that. But there was one big problem with the diagnosis of SLE. As a veterinarian, Tracey McNamara knew it. The virus that causes SLE is passed when a mosquito first bites an infected bird and then, later, a human being. But the birds don’t usually get sick from SLE. They don’t usually die from it. They’re just the carriers, the middlemen. When I spoke with McNamara at Western University of Health Sciences in Pomona, California, where she’s now a professor of pathology, she was blunt.

  “I had barrels full of dead birds,” she told me. “It couldn’t be St. Louis encephalitis.” She explained that, although the CDC was ready to close the case, she couldn’t stop thinking that the dead birds were connected to the sick people. And she knew she was racing the clock. Her avian death toll, especially around the zoo’s flamingo pool, was mounting fast. If someone didn’t correctly identify the killer, not only would the zoo lose most of its birds, but human beings would be waging a public health battle against the wrong disease. Shortly thereafter came word that two of the human patients had died.

  For the rest of the summer McNamara puzzled over the dead street crows, her dead zoo birds, and their possible link to the human deaths from supposed St. Louis encephalitis. Labor Day weekend was the breaking point. Her bird population was ravaged; in rapid succession she’d lost a cormorant, three flamingos, a snowy owl, an Asian pheasant, and a bald eagle. Reports came of a human case of SLE—in Brooklyn. The contagion had spread to a new borough. McNamara stopped following official protocols and called the CDC herself. She offered to share her barrels of downy corpses and the knowledge she had gleaned from all her work in the lab. As she put it, she’d already “ruled out the usual suspects for them”—including St. Louis encephalitis.

  Expecting gratitude for the offer of her data set, she was unprepared for what came next. After a terse exchange she calls “condescending,” the CDC official she spoke with told her in no uncertain terms that the agency would be sticking with its diagnosis of SLE. She could keep her birds, and her concerns, to herself. The CDC solved human, not animal, outbreaks. McNamara was surprised by the slammed door—she says the official actually hung up on her—and bewildered by the repeated rebuffs when she called back.

  McNamara—and, at that moment, the health of animals and humans throughout New York—had fallen victim to that polarizing hypocrisy at the center of medicine and public health. Veterinarians and physicians rarely communicate with each other as equal colleagues.

  In her lab in the Bronx, surrounded by dead birds and reports of dying people, and with seemingly no one in the human medical establishment willing to listen, McNamara felt that gulf acutely. Frustrated, yet determined to get to the bottom of the deadly mystery, she began working her other contacts. She sent infected bird tissue samples to a U.S. Department of Agriculture (USDA) lab in Iowa. A different lab in Wisconsin tested bird tissues for SLE and came up negative.

  Then the Iowa lab turned up something so decisive and chilling that, McNamara said, it made her “hair stand on end.” Whatever this pathogen was, it was only forty nanometers in diameter. And that probably meant it was a flavivirus—related to yellow fever and dengue fever. Working with flaviviruses requires special protective clothing and containment and disposal measures, none of which she had used in her lab while handling the specimens. “That night,” she told me, “I went home and wrote my will.” The USDA lab contacted the CDC with the latest findings. The CDC remained frustratingly unresponsive.

  At two in the morning a few nights later, McNamara sat straight up in bed. She suddenly knew what she had to do. She needed a lab with a higher biohazard safety level. A lab with pathologists who’d seen everything and had a range of experience with infectious agents. “That’s when it clicked,” McNamara told me. “I had to call the army.” The next morning she begged the U.S. Army infectious diseases lab at Fort Detrick, Maryland, to take a look. Within forty-eight hours and in a collaboration McNamara calls the “best of what science can be,” the army lab had confirmed McNamara’s suspicions. This
wasn’t St. Louis encephalitis. It was a flavivirus.

  The virus turned out to be a mosquito-borne pathogen never before detected in the United States—indeed, in the entire Western Hemisphere: West Nile virus. At that point, CDC officials admitted they’d been wrong. They retracted their diagnosis of St. Louis encephalitis and announced the historic and disconcerting arrival of West Nile virus on North American shores. The pathogen quickly migrated across North America, reaching California in 2003. Now it resurfaces each spring and summer throughout the United States, Canada, and Mexico with that year’s crop of hungry mosquitoes.

  It’s hard to say how many lives would’ve been saved had the human medicine establishment listened to a veterinarian from the beginning. The 1999 West Nile epidemic killed seven people and caused sixty-two known cases of encephalitis. In the years since it first emerged, it’s believed to have caused nearly thirty thousand people to get sick and more than a thousand to die. Then there are the animal casualties: thousands of wild and exotic birds—and quite a number of horses—that died from the virus, silently and uncounted.

  But the misdiagnosis was a turning point of sorts for public health in the United States. In a report to Congress detailing the outbreak a year later, the U.S. General Accounting Office (now called the Government Accountability Office) admitted that the experience could “serve as a source of lessons” for preparing public health officials to deal with crises of “uncertain causes.” (The report, dated exactly one year before the 9/11 terrorist attacks, also suggested that the West Nile event could model how to guard against biological terrorism.)

  Tucked beside the usual calls for better communication among government agencies was what at the time was a striking proposal: “The veterinary medicine community should not be overlooked.” The CDC heeded the GAO’s call and created a new department in 2006: Zoonotic, Vector-Borne, and Enteric Diseases. Charged with monitoring food safety and bioterrorism, it was, significantly and symbolically, headed by a veterinarian, not an M.D. (After only a couple of years, the fledgling department was rolled into a bigger division called the National Center for Emerging and Zoonotic Infectious Diseases.)

  Other groups in the United States and around the world have begun to adopt a more species-spanning outlook as well. Bird-watchers, hunters, hikers, and field geologists are invited to upload information about sick or dead animals they encounter onto web-enabled tracking sites that monitor wild-bird and other animal-borne illnesses. The University of Pennsylvania has long had close ties between its veterinary and medical schools, as have Cornell and Tufts. The Canary Database, named for the proverbial sentinels in coal mines and headquartered at the Yale School of Medicine, is a clearinghouse for information about zoonoses (diseases that spread from animals to humans, like West Nile virus and avian influenza), possible bioterrorist attacks, endocrine-disrupting chemicals, and household toxins such as lead and pesticides. The U.S. Agency for International Development (USAID) has funneled hundreds of millions of dollars into the Emerging Pandemic Threats program, which has a mission statement that couldn’t be any clearer: “To pre-empt or combat, at their source, newly emerging diseases of animal origin that could threaten human health.”*

  Jonna Mazet, the U.C. Davis veterinarian who runs a portion of the USAID program called PREDICT, has arguably the most daunting job: like a CIA officer monitoring terrorist activities, she scrutinizes the “viral chatter” coming out of global hot spots in the Amazon, the Congo Basin, the Gangetic Plain, and Southeast Asia. “We don’t know what diseases are out there,” Mazet says. “We have … to try to find the unknown before it spills out and makes the next pandemic. Some people call us virus hunters.”

  Yet even with government money from many countries around the world, as well as funding from international charities, the discrepancy between what goes into preventing disease outbreaks and what goes into postoutbreak triage is huge. “Over $200 billion of economic losses over the past two decades has gone into responding to disease outbreaks,” says Marguerite Pappaioanou, an epidemiologist, veterinarian, and former executive director of the American Association of Veterinary Medical Colleges. “The money is clearly there. It’s a question of where we decide to spend it.” In other words, if an ounce of prevention is truly worth a pound of cure, then strengthening these programs would not only massively decrease suffering and death, but could also save money.

  Yet a small but growing number of veterinarians and doctors have realized something in the last few years. The health of all our patients depends on opening a permanent, two-way dialogue. We don’t have to leave collaboration to government policy makers and academic institutions—although their work is critical. We can treat the shared diseases of all animals, including humans, by taking a multispecies—that is, zoobiquitous—approach in our daily practices.

  The effort can be truly low tech and grassroots. Recently a third-year veterinary student on the island of Grenada was holding a free vaccination clinic for neighborhood dogs and cats. She was approached by a local woman, who angrily asked why the animals received free health care while the people were left to fend for themselves. Realizing she had no good answer, the resourceful student, Brittany King, set to work creating a One Health clinic. She recruited students from a nearby medical school and started holding events that offered free vision, hearing, blood pressure, and breast exams for people … and vaccinations, wound treatment, deworming, and nail trims for animals. The students handed out flyers describing common zoonoses and encouraged people to be on the lookout and to report symptoms they observed in their animals.

  A program at Tufts, in Massachusetts, has paired children and dogs with similar heart ailments to help demystify the condition for the children and their concerned parents. Similarly, Winter, the dolphin with the prosthetic tail portrayed in the 2011 movie Dolphin Tale, inspires children who have artificial limbs.

  My own zoobiquitous journey has utterly changed how I practice and teach medicine. Along with Stephen Ettinger, a pioneer and leader in veterinary medicine, I’ve started teaching a course on comparative cardiology to UCLA medical students. Recently my cardiology colleagues and I sat, rapt, listening to one of Ettinger’s former students present an intriguing case of a life-threatening arrhythmia. It was the sort of medical mystery physicians enjoy as much as reading a chapter in an Atul Gawande book or watching a good episode of House, M.D. But in this case, the patient was a rottweiler mix named Shakespeare. The diagnostic strategy we arrived at—from lab tests to medications—for the four-legged patient was all but identical to one we’d recommend to a human patient with a similar disorder.

  Along with faculty from the U.C. Davis School of Veterinary Medicine and the veterinarians at the Los Angeles Zoo, I hosted a conference at UCLA School of Medicine in 2011 that brought together physicians and veterinarians who take care of the same diseases in different species. More than two hundred doctors and students from both sides of the species divide spent an academic morning session at UCLA hearing about patients, both animal and human, who were suffering from brain cancer, separation anxiety, Lyme disease, and heart failure. During afternoon “walk-rounds” at the Los Angeles Zoo, veterinarians and physicians compared notes on the animal patients: a rhino recovering from cancer, a lion who’d survived a near-fatal heart condition, condors fighting lead poisoning, and a monkey under treatment for diabetes.

  You could say one of the most exciting new ideas in medicine today is something our ancestors took for granted and we somehow forgot—that humans and animals get the same diseases. By working together, physicians and veterinarians may be able to solve, treat, and cure patients of all species.

  There is, after all, something truly awe inspiring about seeing the world through genetic and evolutionary connectedness—almost a unified field theory of biology. It reminds us of our shared predicaments; it broadens our empathy and understanding.

  And it keeps us safer. Preventive medicine isn’t just for people. Keeping animals healthy ultimately help
s keep humans healthy. And appreciating these crucial connections readies us to face and fight the next contagion.

  Ten years after West Nile hit New York, the world’s public health systems mobilized to fight another zoonosis: swine flu, or H1N1.† One of the many headlines from this 2009 pandemic was a disconcerting fact. During its infectious journey around the world, the “human” flu virus had acquired genetic material from pig and bird flu viruses

  While the general public may have been surprised by this news, veterinarians and physicians were not. Influenza viruses are notorious shape-shifters. They mutate easily, which is why every year brings a new flu vaccine—each one a variation on preceding themes. But flu viruses can perform another trick. If two different strains, say pig and human, find themselves occupying a single cell in your body at the same time, they can literally trade sections of their genetic code with each other. A new, blended virus can result.

  What veterinarians know—and physicians might not—is that flu viruses prowl many animal populations besides pigs and birds. Specific strains of dog, whale, mink, and seal flu have all been identified. Given the opportunity, they could blend with the human strain. Although these volatile viruses haven’t, as of this writing, crossed over into human populations, they are being closely tracked by veterinary epidemiologists.

  The 2009 swine flu outbreak was but the latest wave in an ocean of diseases emerging from the jungle, the factory farm, the beach, the backyard bird feeder … perhaps even the doghouse and the litter box. The avian flu scare of 2005, the severe acute respiratory syndrome (SARS) panic of 2003, the monkeypox eruption the same year, the Ebola worry of 1996, the mad cow terror in Great Britain in the late 1980s—exotic zoonoses are nothing new. Think of a big, infectious killer and it’s probably zoonotic, spread or harbored by other animals. Malaria. Yellow fever. HIV. Rabies. Lyme disease. Toxoplasmosis. Salmonella. E. coli. These all started in animals and then jumped into our species. Some spread to us via insects like fleas, ticks, and mosquitoes. Others move around in feces and meat. In some cases, the pathogens leave their animal reservoir, mutate, and evolve into bespoke superbugs especially tailored for human-to-human spread.