An Archaeological Perspective on Parasites

I've been doing some reading on the history of parasitic diseases and what doctors did to help their patients. I came across a series of interesting articles, from an archaeological perspective. A leading parasitologist has taken a historical look at the issue from millenia, to new settlers into the Americas, up to present day. Here is the first article in a series which is rather interesting.

To learn about grisly parasites that have afflicted North and South Americans for millennia, researchers are studying the mummified remains of people the parasites killed

IN A DUSTY STORAGE ROOM TURNED MAUSOLEUM IN THE CHILEAN CITY OF Arica, Bernardo Arriaza gazes down at the body of another dead child. It's an austral autumn afternoon during the Third World Congress on Mummy Studies, and Arriaza is making the most of a few stolen hours away from the conference room. In shadows cast by rows of shelving, the young physical anthropologist from the University of Nevada closes one box and opens another. Inside, a mummified child stares out through a crumbling mask of bluish gray clay. It's eyes are open, its round mouth agape, and bundles of sticks, reeds, and ash bulge from its narrow chest. Arriaza slips the lid back on and glances up at shelves filled with other small gray boxes. "There are a lot of children," he says.

The mummies in this room were exhumed from the sands of the Atacama Desert, one of the driest places on Earth; all were members of the Chinchorro, a coastal people who fished northern Chilean waters from 5500 to 500 B.C. The Chinchorro mummies include the oldest ever deliberately created, which go back 7,000 years, millennia before the Egyptians conceived of such a notion. Eviscerated, dried, stuffed, covered in colored clay, and fitted with wigs, many look more like modern art than human beings. The Chinchorro so loved their dead, it seems, that they were reluctant to part with them. They kept them nearby, continually repainting and touching up their work. "They did not separate death from life," says Arriaza.

The people who crafted such immortality always had plenty of work. Despite ocean waters teeming with fish and lands free of mod em pollutants, the Chinchorro were plagued with mysterious ailments. According to one study, a quarter of their children perished before reaching their first birthday. More than a third suffered from infections that eroded their leg bones. And one in every five Chinchorro women was stricken with bones so porous that her vertebrae splintered from the weight of her own flesh. The average Chinchorro lived just 25 years.

PRECISELY WHAT WEAKENED AND killed the Chinchorro is a question that Fascinates Arriaza and his colleague Karl Reinhard, an archeoparasitologist at the University of Nebraska at Lincoln. For decades, says Reinhard, scientists regarded the ancient Americas as a healthy; parasite-free paradise. Of the dozens of parasites that rampaged through the Old World--armies of flukes that burrowed through lungs and livers, knots of writhing roundworms that blocked intestines and gobbled undigested food, masses of protozoans that invaded nerve tissues and poisoned cells--few were thought to have accompanied humans to the New World. Most parasitic species, it was thought, evolved only after people domesticated livestock, greened farmlands with irrigation, and crowded together in dries, events that took place long after Ice Age Asian hunters set off for the New World. The few parasites that had learned to infect those prehistoric migrants were deemed too delicate to have survived the long, frozen trek across Beringia, the land bridge that joined northeastern Siberia and Alaska during the last ice age. Few researchers gave any thought to potential New World parasites. "So as late as 1981," marvels Reinhard, "parasitologists in general believed that the New World was essentially free of human parasite disease, with the exception of enterobiasis," an infection caused by pinworms.

But in recent years, Reinhard and others have shown that these assumptions were mistaken. While examining human remains, including the mummies of ancient seal hunters in Alaska, prehistoric cave painters in southern Texas, and Inca corn farmers in Peru, they have detected a host of parasites throughout the ancient New World. Some, says Reinhard, weathered the Beringian cold; others, native to the Americas, assailed humans as they encroached on new forests and coastlines. And the diseases they spawned took a high toll. In the Arctic, for example, hunters perished from heart failure as armies of tiny nematodes invaded their muscles. In the Great Basin of the United States, thorny-headed worms pierced the intestinal walls of foragers. And in the South American Andes, protozoans ulcerated and rotted farmers' throats, mouths, and lips. "The hard data of paleopathology show that many people were as sick as dogs," says Reinhard.

Such findings "really give you a window into the lives of these people," says John Hawdon, a parasitologist at the Medical Helminthology Laboratory at Yale. "Ritual life has always been an important thing in archeology, but the health of a people is just as important because it determines a lot about how they interacted with each other. One could argue that the Aztecs performed many human sacrifices because of protein deficiencies and malnourishment. And who knows what caused that? Hookworms could have been involved." Moreover, the implications extend far beyond archeology. By charting the rise and spread of parasites in the New World, Reinhard and others are now shedding light on both the evolution of these pathogens and the origins of ancient plagues such as Chagas' disease, which currently infects an estimated 370,000 Americans and 16 to 18 million inhabitants of Central and South America. And this, emphasizes Reinhard, is only the beginning. "If we look at the research questions of the past, it was `Can we find the worms?' But in the future, our questions are going to relate to the influence of climate change on the parasites and how this archeological evidence of emergent and reemergent disease can contribute to our understanding of emerging diseases today."

There are more stories if you're interested at the link below (hit next): 

http://www.findarticles.com/p/articles/mi_m1511/is_1998_Dec/ai_53268608 

This site also has historical articles to read; such as, "Evolution of Ascarisis in Humans and Pigs".

http://memorias.ioc.fiocruz.br/98sup/98sup.html