Study claims to have discovered key source of AIDS

An international team of researchers claimed to have found when and from where the strain of the HIV virus has entered the United States. The AIDS virus, HIV-1, arrived in the US from Africa via Haiti in about 1969 before spreading further, according to a new research conducted by the team in the Proceedings of the US National Academy of Sciences.

According to the study, publishing this week in the Proceedings of the National Academy of Sciences, the HIV virus, which predominates in the US, Europe, large parts of South America, Australia and Japan, has hit the country a decade earlier than previously assumed, most probably carried there by a single Haitian immigrant.

The strain, "HIV-1 group M subtype B”, that probably migrated to the U.S. in 1969 rather than the mid 1970s as was previously believed, is the dominant strain of the lethal AIDS virus in most countries outside sub-Saharan Africa, and also the first human immunodeficiency virus discovered.

The study says that most HIV/AIDS cases in those countries descended from a single common ancestor from Haiti.

"Haiti was the stepping stone the virus took when it left central Africa and started its sweep around the world," said Michael Worobey, an assistant professor of evolutionary biology at the University of Arizona in Tucson, and senior author of the study. "Once the virus got to the US, then it just moved explosively around the world," he added.

To reach their conclusion, Worobey and his colleagues conducted genetic analysis of archived blood samples from five early AIDS patients, who were all immigrated to the United States from Haiti. The team also analyzed genetic sequences from another 117 worldwide AIDS patients.

Using this data, they first prepared a family tree for the virus and then traced the spread of the epidemic from the United States back to Haiti, where the virus entered in about 1966 from Africa where HIV is thought to have originated.

Funded by the National Institutes of Health, the David and Lucile Packard Foundation and a University Research Fellowship from The Royal Society, the research suggests a more than 99 percent probability that the virus went from Africa to Haiti to the United States.

HIV AIDS is spreading like forest fire worldwide, affecting nearly 40 million people around the world. The lethal infectious disease is now transmitted mostly during sex between a man and a woman.

The UN AIDS agency, which is playing the leading role in the battle against the disease, reported in November 2006 that Sub-Saharan Africa is the worst hit region by the HIV virus, accounting for almost two-thirds of all HIV infections and 72 percent of global AIDS deaths.

The epidemic has engulfed more than 25 million sub-Saharan Africans since the incurable disease was first emerged in 1981. A huge and disproportionate 59 percent of sub-Saharans Africans with HIV are women, the report added.

According to the latest 2006 estimates released recently by the National AIDS Control Organization (NACO), supported by UNAIDS and WHO, national adult HIV prevalence in India is approximately 0.36%, which corresponds to an estimated 2 million to 3.1 million people living with HIV in the country.