Developments in Brief : 2 New AIDS Viruses Appear to Be Variants

Two new AIDS viruses discovered in West Africa in 1985 appear to be variants of the same virus, according to AIDS researchers at a medical meeting in San Francisco last week. But the French and American scientists who discovered the viruses still do not agree on whether these variants pose significant health threats.

One virus, LAV-II, was isolated by a team led by Dr. Luc Montagnier of the Pasteur Institute in Paris; the other, HTLV-IV, was discovered by Dr. Myron Essex and other researchers at the Harvard School of Public Health.

Montagnier and Essex believe the new viruses are transmitted by sexual contact and through the blood. But they continue to present conflicting data on the ability of the variant viruses to cause acquired immune deficiency syndrome.

Montagnier believes the variant viruses are just as deadly as the original AIDS virus. He said he has isolated the LAV-II virus from 30 patients from West Africa, including 22 with illnesses related to AIDS.

Essex says 5% to 15% of adults in West Africa are infected with the new viruses, but very few cases of AIDS have developed. By comparison, in Central Africa, where a comparable percentage of adults are infected with the AIDS virus, thousands of cases of AIDS have developed.

Essex based his conclusions on an analysis of blood samples from 4,428 adults in six West African nations, the most comprehensive study yet of the extent of infection with the variant AIDS viruses. In another study, involving 50 prostitutes from Senegal who have been infected with HTLV-IV for 18 months or more, none has become ill.

“We should not jump to conclusions that there is a new terrible AIDS virus that is causing an epidemic,” Essex said. “There is a virus in West Africa which is infecting a lot of people, but it is not causing a lot of illness.”

But Montagnier disagreed, saying: “It is just a matter of time” before more AIDS cases are seen.