Thanks to Catalin for the link.

http://www.nytimes.com/2008/02/07/science/07lice.html?_r=1&oref=slogin

Scientists Say Mummies' Lice Show Pre-Columbian Origins

By JOHN NOBLE WILFORD

When two pre-Columbian individuals died 1,000 years ago, arid conditions in the region of what is now Peru naturally mummified their bodies, as well as the lice in their long, braided hair.

That was all scientists needed, they reported Wednesday, to extract well-preserved louse DNA and establish that lice had accompanied their human hosts in the original peopling of the Americas, probably as early as 15,000 years ago. The DNA matched that of the most common type of louse known to exist worldwide now and also before Europeans colonized the New World.

The findings absolve Columbus of responsibility for at least one wrong unintentionally wrought on the people he found in the Americas and called Indians. The Europeans who followed Columbus to America may have introduced diseases, namely smallpox and measles, but not the most common of lice, as had been suspected.

Of possibly more importance, evolutionary biologists say, studying parasites may become a valuable new tool in scientific efforts to understand human migrations and the spread of disease. Lice have been found on Egyptian mummies, for example, but they have yet to undergo genetic examination.

The analysis of lice from the Peruvian mummies is described in a paper to be published Feb. 15 in The Journal of Infectious Diseases. The principal authors are Didier Raoult of the French National Reference Center for Rickettsial Diseases in Marseille and David L. Reed of the Florida Museum of Natural History in Gainesville.

The scientists independently studied samples from the two mummies, which were among those collected between 1999 and 2002 in the high coastal desert of southern Peru by Sonia Guillén, a Peruvian anthropologist. Looters had destroyed the bodies, leaving only the heads of people who had died around the year 1025. Lice have also been recovered from New World mummies as much as 10,000 years old.

The two laboratories' DNA test results were identical, the researchers said. They showed that people in the 11th-century Americas already had the prevalent type A strain of lice.

The researchers said "the most likely theory" was that type A head and body lice originated in Africa and were distributed worldwide long ago. Type B, which infests only the head, is also common, and type C is rare, found primarily in Ethiopia and Nepal. Pubic lice are an entirely different strain.

Lice from other mummies with hair still intact, the scientists said, may "help us understand the distribution of types A and B in the Americas and the Old World before globalization."

Diseases spread by lice, though not a major problem in much of the world, include epidemic typhus, trench fever and relapsing fever, which are now treatable with antibiotics.

Dr. Reed, an evolutionary biologist, said in a telephone interview that although the discovery of type A lice in pre-Columbian America acquitted Europeans of having introduced the parasites, explorers might now be implicated in spreading a louse-borne disease back to the Old World.

"The typhus bacterium may be native to the Americas," he said. "There are no records of typhus in Europe until the 1500s."