The AIDS epidemic drew attention to KS, a previously rare and little studied condition. The epidemiological evidence summarized here strongly suggests that the disease is caused by a transmissible agent, in addition to HIV. Sexual contact is the most important mode of transmission of the agent, although transmission by blood and perinatally may also occur (Beral et al, 1990).
PIP: More and more epidemiologic research points to a transmissible agent as the cause of Kaposi's sarcoma, whether it is linked to HIV infection or not. Further, research indicates that each person's immune status controls its clinical expression. This once rare disease became an epidemic among male homosexuals and foreshadowed the AIDS epidemic. Epidemiologic studies of this phenomenon revealed 2 particular features of Kaposi's sarcoma. First, it is sexually transmitted as is HIV; so the conditions that facilitated HIV transmission and the AIDS epidemic also facilitate transmission of the agent causing Kaposi's sarcoma. Second, immunosuppression allows Kaposi's sarcoma to manifest itself in individuals who are normally asymptomatic carriers of the Kaposi's sarcoma agent; therefore, HIV-induced immunosuppression in carriers of this agent promotes development of Kaposi's sarcoma. Furthermore, this combination explains why it is so very prevalent in people with AIDS. Indeed, Kaposi's sarcoma is often the first manifestation of AIDS, and it appears when immunosuppression status is mild. Its prevalence among people with AIDS in the US and Europe is declining, however. The initial AIDS patients who also had a high incidence of Kaposi's sarcoma were the most sexually active homosexuals. Eventually, AIDS affected the less sexually active homosexuals, who were at lower risk of developing Kaposi's sarcoma than the more sexually active homosexuals. Kaposi's sarcoma rarely occurs in heterosexuals from the US or Europe, but occurs frequently among heterosexuals from Africa or the Caribbean. One can conclude that the prevalence of the Kaposi's sarcoma agent is probably low in heterosexuals in the US or Europe but high in those from Africa or the Caribbean. Other research suggests that the agent can also be transmitted by blood and perinatally.