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HIV-2: a less virulent cousin of HIV-1.

A new report confirms the milder nature of HIV-2, a close cousin of HIV-1. Both HIV-1 and HIV-2 cause AIDS, a disease that decimates the immune system and causes death.

Researchers first demonstrated the existence of HIV-2 in a 1985 study conducted in the West African country of Senegal. Since that time, virologists have shown that HIV-2 is more prevalent in West Africa than HIV-1. And preliminary reports indicated that this virus is less virulent than HIV-1, which is responsible for the vast majority of AIDS cases in the United States.

Now, a study of 574 prostitutes in Dakar, Senegal's capital, quantifies more precisely the characteristics of HIV-2.

U.S. and African AIDS researchers started their study by monitoring prostitutes who were registered by the Senegalese government and therefore were tested frequently for sexually transmitted diseases, such as AIDS.

The researchers discovered dramatic differences when they compared women who became infected with HIV-1 during the study to those infected with HIV-2.

Five years after infection, one-third of the women infected with HIV-1 had progressed to AIDS. In contrast, none of the HIV-2-infected women had developed the disease.

Another key indicator of HIV-2's less vicious nature showed up in a laboratory test of the immune system. Each year, about 10 percent of the women infected with HIV-1 showed an abnormally low number of CD4 T lymphocytes, a type of white blood cell destroyed during the disease process. People with decimated CD4 T lymphocytes often develop the opportunistic infections that lead to death. Annually, just 1 percent of the HIV-2-infected prostitutes experienced such a plunge in CD4 counts. The study appears in the Sept. 9 Science.

For people infected with HIV-2, long-term survival without developing severe illness or AIDS may prove the rule rather than the exception, says lead author Richard Marlink of the Harvard School of Public Health in Boston. Additional studies of the differences between the two viruses may provide clues about how to fight HIV-1, he adds.
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Title Annotation:women with HIV-1 progress faster to AIDS than women with HIV-2
Publication:Science News
Article Type:Brief Article
Date:Sep 17, 1994
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