Quest for AIDS Vaccine Leads to African Virus

Researchers from Africa and the United States are exploring the possibility that a virus isolated in healthy West Africans may be helping to protect them from getting AIDS.

Although cases of AIDS are said to be common in Central Africa, only one case is known to have occurred among the Senegalese in West Africa, Dr. S. M’Boup of the Center for Sexually Transmitted Diseases in Dakar, Senegal, told an international conference on AIDS here Saturday.

According to Dr. Max Essex of the Harvard School of Public Health, the virus found in the Senegalese is being studied to see whether it may be used to prepare a vaccine against AIDS.

Similar to Virus in Monkeys

The virus is almost identical to one found in healthy green African monkeys, Essex said, and it is even more closely related to HTLV-III/LAV, the virus that causes AIDS.

Essex believes that the AIDS virus and the newly isolated green African monkey virus, known as STLV-AGM, are members of the same family. Originally, he theorizes, they were all one virus that was benign and existed only in monkeys.

In the recent past, he believes, that virus somehow infected humans, where it mutated and became a much more virulent organism that is the cause of acquired immune deficiency syndrome. But some humans presumably have retained the benign version, which because of its close relationship to the AIDS virus, stimulates the immune system to give humans some protection against the AIDS virus. It is this feature that makes scientists believe that the similar monkey virus may be useful in the making of a vaccine.

It is still unclear whether the virus might be responsible for illnesses that are not AIDS related.

How the virus got from monkey to man is also still speculative. Essex suggests that green African monkeys, which are commonplace throughout tropical Africa, may have infected human blood by biting a human trying to capture them. The virus was then passed to other humans by sexual transmission or by any means in which blood is exchanged, Essex believes.

The findings about the new virus tend to support the theory that AIDS originated in Africa, which has been a sensitive issue during the conference attended by 700 doctors and researchers from 51 countries, 16 of them African nations.

At a news conference after the closing session on Saturday, Dr. David Serwadda, a Ugandan now at the Institute of Cancer Research, Newcastle upon Tyne, England, said the media have given the public an “exaggerated” impression of the extent of AIDS in Africa.

“When Americans read that in Uganda or Kenya there is a 10% prevalence of antibodies (to the AIDS virus), they think everybody there is walking around with AIDS,” he said. “But those are small samples that are not representative of the whole population.”

When newsmen pointed out to Serwadda that those reports came from reputable medical journals, he warned that the press “should never believe everything in Western medical journals.”

The conference itself, however, heard a number of reports by African, European and American researchers about the high prevalence of antibodies to the AIDS virus in segments of the populations in Central Africa.

High Incidence of Antibodies

Among them were recent blood studies done in Rwanda, Zambia and Uganda, which indicated that about 10% of the population had antibodies to the HTLV-III/LAV virus. That figure is many times higher than for the general population of the United States and Europe.

Another study presented to the conference showed that the population of Kinshasa, the capital of Zaire, has one of the highest rates in the world of positive tests for the presence of antibodies to the AIDS virus.

As is the case in the United States and Europe, AIDS in Africa primarily strikes special groups of high-risk individuals.

Several reports presented at the symposium strongly suggest that in Africa the virus is mainly transmitted by heterosexuals who frequent prostitutes.

The significance of prostitution in transmitting the disease seemed especially clear in a study by University of Brussels researchers in Rwanda, where there is one female AIDS patient for every two male patients.

The male AIDS patients had a higher number of different female partners and of contacts with prostitutes than did healthy males. Among the female AIDS patients, 33% were a spouse of a promiscuous male, 66% were single and 42% were prostitutes. None of the males or females were bisexual or intravenous drug users, according to the researchers.

High-Risk Groups in U.S.

Homosexuals and intravenous drug users are the two highest-risk groups in the United States and Europe.

In the United States, case records by the Centers for Disease Control reveal that the percentage of AIDS patients who are heterosexual has not increased since 1981. This indicates that the threat to heterosexuals in the United States is not great.

One reason often given for the relative unimportance of heterosexual involvement in the United States is that transmission of the virus from a female to a male appears to be more difficult than transmission from a male to a female.

However, the African data indicates that the frequency of the exposure of a male to a female AIDS carrier--such as a prostitute--makes being a promiscuous male risky. In the United States, researchers say, this is particularly true because many prostitutes are also high risk by virtue of being intravenous drug users.

A list of recommendations to be given to African governments and signed by about 50 doctors from Africa who attended the conference included one saying that sexual promiscuity is a high-risk factor in Africa and that the public there must be informed.

The document also declared that the conference revealed no conclusive evidence that AIDS originated in Africa.

‘Not an African Problem Alone’

“It is not an African problem alone,” the statement said.

In another closing statement, Dr. Nathan Clumeck of the University of Brussels, organizer of the meeting, said scientific research on the origin of the virus is fundamental if the epidemic is to be controlled.

In an earlier statement, Clumeck, who helped bring to light the seriousness of the AIDS problem in Africa by diagnosing Zairians who came to Belgium after 1979 for treatment of a then-unknown ailment, noted that many countries do not now report AIDS cases to the World Health Organization.