The World Health Organization, seeking to quickly gather accurate information on the health threat posed by recently discovered variant AIDS viruses, will convene an international conference on these viruses early next year.
"It is clear that (these viruses) are causing a lot of disease but we are not sure how much," Dr. Jonathan Mann, the director of the organization's AIDS program, said in a telephone interview from Geneva on Saturday.
Mann said he will announce the conference Tuesday at a WHO regional meeting on AIDS in Africa, being held in Brazzaville, the Congo. It is expected to take place in Africa, but an exact date and time have not been set.
Mann confirmed warnings last week by Dr. Luc Montagnier of the Pasteur Institute in Paris that a virus he discovered in West Africa last year, called LAV-II, appears to be just as deadly as the original AIDS virus.
"It is clear from Dr. Montagnier's data that LAV-II is associated with a clinical picture which is virtually identical to AIDS," Mann said. But the WHO official said further studies are necessary to determine if LAV-II is a major cause of AIDS in West Africa, where the disease is less common than in Central Africa.
The WHO conference next year will focus on LAV-II and another human virus related to the AIDS virus called HTLV-IV. Unlike LAV-II and the AIDS virus, HTLV-IV does not appear to cause disease. It was discovered last year, also in West Africa, by a research team led by Dr. Myron Essex of the Harvard School of Public Health.
In the last year, researchers throughout the world have found that isolates of the original AIDS virus show a great deal of variation in their genetic material and protein coat.
This variation complicates efforts to learn if viruses isolated from AIDS patients are different enough to be considered new viruses. Such differences are significant because new viruses may need to be detected by other blood tests and perhaps treated with different experimental medicines.
One such possible new virus, isolated in Sweden from immigrants from the West Africa country of Gambia, is being studied at the National Cancer Institute by a research team headed by Dr. Flossie Wong-Staal. But a member of the research team said Saturday that it was premature to consider this isolate a new AIDS virus until further studies are completed.
Mann said he would "not be surprised" if other AIDS-related viruses, called retroviruses, are discovered within the next year.
"We all believe that the retroviral map of the world has not yet been filled in," Mann said.
But he cautioned that strategies to control the deadly disease through education and the prevention of disease transmission by sexual contact or through the blood would not be affected at the present time by the discovery of variant AIDS viruses.