Doctor to the mummies

A child with tuberculosis

In 1979, Zimmerman took part in an expedition to Egypt, where he examined the mummified body of a 6-year-old child dating back to 1300 B.C.

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By staining samples of its lung tissue, he found the pathogen that causes tuberculosis, thus establishing the oldest known case of the disease. The only previous evidence of TB dating back that far had come from artwork depicting figures with bone deformities characteristic of the disease.

In 1991, the head of the anthropology department at Austria’s University of Innsbruck called him after a 5,300-year-old frozen body, “Otzi the Iceman,” was found in the nearby mountains, preserved by ice and snow. He missed his chance to examine the body when scientists realized that Otzi’s final resting place was on Italian side of the border and that the Austrians had to give him up to an Italian museum. There, a CT scan revealed the cause of death: an arrowhead lodged in Otzi’s left shoulder.

Over the years, Zimmerman has seen mummies with arthritis, club foot (King Tut suffered from it), cirrhosis of the liver and plaque in their arteries — ailments similar to what doctors see in autopsies today.

It’s not hard to find mummies, he said. When modern Egyptians built railroads, so many mummies turned up during the digging that workers burned them for warmth. Since that first Smithsonian mummy, he said, he has examined 200 to 300. When he started out, he did a complete autopsy, cutting up the body and removing the organs. Now, he uses less-damaging procedures, imaging them with CT scans and inserting endoscopic instruments through small holes.

What amazed him was that among all these mummies, he saw only two cases of cancer, though he says tumors are easy to spot. During a recent talk at Villanova, he showed a slide of a rectal cancer found in a middle-aged Egyptian mummy, explaining how the cells stained a distinct color and showed signs of abnormal cell division.

Controversial speculation

Zimmerman and University of Manchester professor Rosalie David, who founded the university’s renowned Egypt Mummy Project, wrote a 2010 paper for the journal Nature on the lack of mummified cancer and their speculation that cancer might be more tied to modern environments than has been assumed. Zimmerman attributes most of the difference to the modern prevalence of smoking: There’s nothing in the historical or archaeological record to suggest that ancient Egyptians smoked.

The paper stirred up controversy, with some questioning whether the low cancer rates in ancient people are merely a consequence of shorter life spans — perhaps people simply didn’t live long enough to get cancer. But even taking age into account, Zimmerman said, there’s surprisingly little cancer. Besides, he said, he sees osteoarthritis, clogged arteries and other diseases of aging in these mummies. Some of the pharaohs lived past 90.

Geneticist Mary Daly of Philadelphia’s Fox Chase Cancer Center said it’s also likely that obesity plays a role in making cancer so much more common today than it was in ancient Egypt. If you took away cigarettes and obesity from today’s population, Daly said, you’d see a drastic drop in cancer rates. That’s essentially the population you’re studying in ancient Egypt.

Other researchers share Zimmerman’s interest in diseases of the distant past, though most study bones rather than mummies. Bones have revealed ancient cases of osteoporosis and a striking decline in height and general health in a number of societies after the adoption of agriculture, possibly due to unsanitary conditions and a sudden shift from varied diets to ones based primarily on grain.

While the anthropologists who study bones have the advantage of much more numerous samples, Zimmerman’s mummies preserve more information. Both types of studies can provide insights into the causes of diseases, said Ohio State University anthropologist Clark Larsen, who heads the Global History of Human Health Project.

Zimmerman, 75, is concentrating on passing his knowledge down to a next generation of researchers. They have tools he never dreamed of back when he started out, he said. CT scanning has improved to where researchers can see detail unimaginable a decade ago, and in the last few years scientists have developed the ability to extract and sequence DNA from scraps of ancient bones and tissues.

There’s a more interesting future than ever, he said, for those who choose to study the distant past, and there are more connections to be made to the diseases of modern man.

Flam writes the Lightning Rod blog for WHYY’s NewsWorks. She has been a science columnist for the Philadelphia Inquirer and written for the Economist and Science. Her latest book is “The Score.”