Study shows lice were carried from Africa

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Head lice taken from 1,000-year-old mummies in Peru support the idea that the little creatures accompanied humans on their first migration out of Africa, 100,000 years ago, researchers reported on Wednesday.

Genetic tests showed the lice are nearly identical to strains found around the world that have been dated to when humans first began to colonize the rest of the world.

"It tells us that this genetic type got around the globe right as humans spread and migrated around the globe," said David Reed of the University of Florida, who worked on the study.

"We know that this parasite was distributed all over the globe along with us," Reed said in a telephone interview.

Writing in Journal of Infectious Diseases, Reed and colleagues noted that there are three known strains, or clades, of head lice -- A, B and C.

Clade A is found everywhere, clade B is common in both North America and Europe, and clade C is rare. There had been a theory that clade B evolved separately in the Americas and that European explorers carried A to the Americas and brought B back to Europe with them.

Reed, who showed in 2004 that clade A dated back to early humans, said he got to test the idea by accident.

The lice were collected off the heads of two mummies found in the southern Peruvian coastal desert. "The mummies belonged to the post-Tiwanaku Chiribaya culture," the researchers wrote. They were dated to around 1000 AD.