New AIDS Timeline Revealed

According to a new study, AIDS arrived in the United States via Haiti around 1969.

WASHINGTON (Reuters) - The AIDS virus invaded the United States in about 1969 from Haiti, carried most likely by a single infected immigrant who set the stage for it to sweep the world in a tragic epidemic, scientists said on Monday.

Michael Worobey, a University of Arizona evolutionary biologist, said the 1969 U.S. entry date is earlier than some experts had believed. The timeline laid out in the study led by Worobey indicates that HIV infections were occurring in the United States for roughly 12 years before AIDS was first recognized by scientists as a disease in 1981. Many people had died by that point.

"It is somehow chilling to know it was probably circulating for so long under our noses," Worobey said in a telephone interview. The researchers conducted a genetic analysis of stored blood samples from early AIDS patients to determine when the human immunodeficiency virus first entered the United States.

They found that HIV was brought to Haiti by an infected person from central Africa in about 1966, which matches earlier estimates, and then came to the United States in about 1969. The researchers think an unknown single infected Haitian immigrant arrived in a large city like Miami or New York, and the virus circulated for years -- first in the U.S. population and then to other nations.

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The researchers analyzed samples from five of these Haitian immigrants dating from 1982 and 1983. They also looked at genetic data from 117 more early AIDS patients from around the world. This genetic analysis allowed the scientists to calibrate the molecular clock of the strain of HIV that has spread most widely, and calculated when it arrived first in Haiti from Africa and then in the United States.

The researchers virtually ruled out the possibility that HIV had come directly to the United States from Africa, setting a 99.8 percent probability that Haiti was the steppingstone. Studies suggest the virus first entered the human population in about 1930 in central Africa, probably when people slaughtered infected chimpanzees for meat.

This study again shoots down the Patient Zero theory that Canadian flight attendant Gaëtan Dugas single-handedly brought AIDS to America, a persistent myth first debunked in 1987 by Dr. Andrew Ross in the American Journal of Epidemiology. Dugas' story was vividly depicted in Randy Shilts' book, And The Band Played On.

So AIDS has been here for at least 38 years, not the 26 years since it was discovered. I'd always imagined that it had been even longer. It's fascinating news, but probably not much use to people living with the disease today.