Border Crosser
CDC Official Battles Bugs that Leap across Cultures—and Species

by Joan Capuzzi Giresi

A tireless crusader for public health at the Centers for Disease Control in Atlanta, epidemiologist Peter Schantz, C’61, V’65, combats zoonoses, infections that naturally jump from animals to people. Schooled in anthropology, Schantz fights most of his battles in developing countries while astutely negotiating local cultural mores. His targets are usually parasites, generally of the slimy variety. He finds his pathogens of choice—zoonotic helminths, or worms—intriguing because of their transmission dynamics within the human population. And he’s gone up against many—tapes, rounds, even tropical guinea worms.

For us who live stateside, where a benign skin rash can trigger frenzied trips to Lyme disease clinics, the thought of living among animals ridden with parasites is, well, unthinkable. But in countries like Mexico, Nigeria, China, and Nepal, dangerous bugs—and the human diseases they bring—are as close as the pig milling at the back door or the dog rolling around with the kids. That’s where Schantz, the anthropologist-veterinarian, comes in.

“ Most cultures have special relationships with their animals,” he says, relationships that can prove harmful. Consider the nomadic sheep herders in Kenya who feed their dogs the Echinococcus-tapeworm-infested viscera of sheep they butcher in the fields. Their families, mixing poor hygiene and close contact with the dogs, ingest the tapeworm eggs released in the dog feces. From feces to fur to hands to mouth. The newly hatched larvae then cause human hydatid disease as they form cysts in the liver, lungs, brain, and other organs. The malady can be fatal if left untreated.

To combat such diseases, Schantz treks the globe collecting samples from slaughtered beasts, diagnosing disease in living animals, and collaborating with local health officials to develop parasite-control programs. He also provides technical consultation for research projects, assembles international teams to fight emerging outbreaks, and develops educational materials for veterinarians and the public.

Although Schantz has achieved what he calls “measurable disease reduction,” parasites are like weeds that must be cut back constantly. Plus, these vermin have a loyal ally in poverty. In his work with populations such as the indigenous natives of Patagonia, who rely on subsistence-level production to survive, Schantz has witnessed the double threat parasites pose. “Animal disease is not only devas-tating from a production standpoint, but because of their poor hygiene, these people are at considerable risk for zoonotic disease.”

In some countries, pigs roam the streets and feed on human feces. Sometimes the family latrine is situated over the pig pen, a cost-efficient system for feeding the pigs while disposing of waste. “Pigs,” Schantz says, “are a brilliant solution to poverty.” Unfortunately, this elimination-feeding chain gracefully completes the life cycle for the pork tapeworm, Taenia solium, which develops in the muscle of pigs that consume human feces containing tapeworm eggs. When people eat undercooked, contaminated pork, they can become infected. The larvae form cysts in major organs, including the eyes and brain, causing the debilitating syndrome neurocysticercosis. Worldwide, the disease affects some 5 million people.

Although poverty is a major force in the poverty-culture-disease triad, culture packs a punch too. “I’ve worked in a lot of cultures that are pretty ignorant of the value of modern medicine,” he says, pointing to some of the livestock producers in Argentina.

Societal norms, Schantz continues, place certain individuals within a population at greater risk. In patriarchal Muslim and Tibetan societies, for instance, the tapeworm infection Echinococcosis is more prevalent in women because it is they who are charged with caring for the dogs, who carry the infection.

Such cultural complexities are a far shot from the white bread America of Schantz’s youth. Growing up in a conservative community in southern New Jersey, exotic places were limited to National Geographic magazine. “I was very intrigued by the idea of jungles and Africa and safaris and being an adventurer,” he remembers. His decision to major in anthropology was a natural next step, one impacted by what he calls the “Peace Corps mentality” of the day. “Being in a world that was rapidly changing, with JFK as president, broadened my whole perspective,” he says. “My under-graduate training at Penn is a large part of what I do today as a public health professional.”

A lifelong animal lover, Schantz spent his college summers caring for cows and plowing fields at a local dairy farm. Once he began veterinary school, he sought ways to blend his passions for human culture and animals. On a summer job with the California Department of Health Services to eradicate Triatoma, the “kissing bug” whose bite causes allergic reactions, he found the answer in public health.

After earning a doctorate in epidemiology from UC Davis, Schantz felt a strong tug coming from the ailing populations south of the border. “I was going to go down there sort of like a Peace Corps person and try to help out,” he recalls, “but the idea that you could make an impact as a veterinarian in preventing disease in animals and people without institutions to support you was such a naïve concept.” So he went to work for the World Health Organization, developing Echinococcus eradication programs in South America. In 1974, he joined the CDC as a commissioned officer in the U.S. Public Health Service. In 39 years of international public health work, he has lived and worked around the globe, primarily in South America.

Schantz applauds the CDC’s international focus, although only about 20 percent of its budget goes to projects outside this country. The domestic achievement that gives him the greatest bragging rights is his fight against trichinellosis, a roundworm infection that people contract from eating undercooked meat containing larval cysts. In the 1970s, nearly 400 people a year were becoming infected, some fatally, from contaminated pork. Schantz and his colleagues lobbied to make trichinellosis a reportable disease; educated physicians, pork producers, and the general public about the condition; and put disreputable pork producers out of business. As a result, pork-related trichinellosis has been nearly eradicated in the U.S.

When he works on rooting out a disease in this country, Schantz thinks outside the borders. Case in point: Brooklyn, early 1990s. Unexplained seizures in a handful of residents of an affluent commu-nity. The cause of the minor epidemic was found to be brain infection with the larvae of the pork tapeworm, a parasite not endemic to the U.S. The malady it inflicts, neurocysticercosis, kills about one in 20. All Orthodox Jews, the infected never ate pork. Schantz blew the cover off the mystery when he determined that the victims were contracting the disease from their Latin American domestic help, who managed food preparation. The disease was passed along because of the poor personal hygiene of the workers, who carried the infection from their native countries.

As the parasites adapt to our more mobile and fast-changing ways, their basic mechanisms remain the same. And Schantz strives to better understand the devious methods of his zoonotic foes—those parasites and other bugs that jump species, cultures, and often geographic boundaries. He shares with them a common trait: He himself, in his work, makes some of those same great leaps.

Joan Capuzzi Giresi, C’86, V’98, is a writer and veterinarian.