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HIV Arrived to US from Haiti and Not Africa

Oct 30, 2007
A new research, performed by a team, led by Michael Worobey, an assistant professor of ecology and evolutionary biology at The University of Arizona in Tucson, and published in the Early Online issue of the Proceedings of the National Academy of Sciences, states that the deadly HIV virus that causes AIDS, presumably came into United States from Haiti somewhere around 1969, which is, in fact, a decade earlier than the majority of scientists believed.

The new study is entitled "The emergence of HIV/AIDS in the Americas and beyond".

"Our results show that the strain of virus that spawned the US AIDS epidemic probably arrived in or around 1969. That is earlier than a lot of people had imagined," outlined Michael Worobey in his statement.

He added that Haiti served as the stepping stone that the virus took after leaving central Africa. Afterwards the virus began spreading worldwide. When HIV arrived to the US, it simply exploded around the world.

Scientists discovered that one common ancestor led to a huge number of HIV/AIDS strains in the United States.

The work of Worobey and his colleagues states that the strain that arrived to the United States in 1969 was HIV-1 group M subtype B. It was the first human immunodeficiency virus ever discovered. It is worth mentioning that this strain prevails among the AIDS strains that are found in majority of countries located outside of sub-Saharan Africa. Almost all of the strains came from one that arrived from Haiti.

Together with his colleagues Worobey analyzed the genes from stored blood samples, gathered from five patients with AIDS, in order to identify the date HIV arrived in the United States.

It's worth noting that all the patients had emigrated from Haiti not so long ago. After analyzing the current samples and samples collected from 117 AIDS patients from around the world, infected with subtype B, scientists were able to build a family tree of HIV genes.

First Worobey and his colleagues analyzed the gene sequences. Afterwards researchers used Bayesian statistics for sifting through all possible HIV trees. In such a way they tried to find those that were closer to the sequences they found.

The probability that HIV arrived from Africa directly to the United States was 0.003 percent. Scientists believe that the most likely the route of the virus was Africa to Haiti to US. The probability of such was 99.8 percent.

It is interesting to note that scientists also discovered, through gene sequence analysis, that the majority of viruses in the United States may have one ancestor, presumably the one that entered the US from Haiti somewhere around 1969.

The team found that there is a great genetic diversity of the subtype B virus in Haiti, even greater than in the United States, Australia, Europe and other countries. According to the researchers, the analysis and establishment of the genetic diversity of HIV within the subtype B could lead to the development of vaccines against the virus for use in Haiti.

Scientists say that the variety of the virus in Haiti is due to the fact that it has lived there longer.

By using older blood samples from their archive, Worobey and his team look forward to trace the HIV ancestry back even further.

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