AIDS Virus Strains
Are Mutating - Test
Concerns Grow
MONTPELLIER, France (AFP) - French and African researchers said Friday that strains of the AIDS virus were mutating, a development with potentially alarming repercussions on testing and treatment for the infection.
Scientists at the Research Institute for Development (IRD) in Montpellier said they had found that two strains of the Type 1 human immunodeficiency virus (HIV), previously thought to be genetically far apart, had combined together.
There are two main types of HIV virus, the precursor to acquired immune deficiency syndrome (AIDS).
HIV-1, the most widespread, has three strains -- M, N and O -- that each have different characteristics.
Until now, conventional thinking was that these groups were so divergent -- genetically more than 50 percent dissimilar -- that there was no risk of recombination between them.
But researchers at the IRD's retrovirus laboratory, working with counterparts in the West African country of Cameroon, said they had isolated and identified a live strain that had combined from group M and group O.
"We found a patient in Cameroon who had been infected by the two strains and, against all our expectations, we found that the two strains had merged, forming a new variant," the head of the team, Martine Peeters, told AFP.
"This supposes that even viruses which are genetically far apart can mix and form a completely new variant."
The discovery, reported in a US publication, the Journal of Virology, could have grave implications in how the AIDS virus is spread, as well as the conventional methods for testing and treating it, she said.
"At the moment, group O is rare. But the fact that it can recombine with another virus may change its characteristics and make it more virulent," she said.
Another problem is screening. Because O is rare, viruses in this group sometimes cannot be detected using commercially-available test kits, and they are resistant to certain anti-retroviral treatments.
Cameroon has been the theatre of a previous landmark discovery in AIDS research.
It was there that a French researcher, Francois Simon, first identified the group N strain in September 1998.
Group N is genetically close to a virus that prevails in chimpanzees, leading to speculation that humans contracted it from eating ape meat. The HIV strain that is most prevalent in western countries is Group M.
The other type of AIDS virus, HIV-2, is mainly prevalent in Africa's Great Lakes region.


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