High proportion of HIV-2 and HIV-1/2 double-reactive sera in two Indian states, Maharashtra and Goa: first appearance of an HIV-2 epidemic along with an HIV-1 epidemic outside of Africa.

The seroprevalence of HIV-1 and HIV-2 infections was determined in selected groups of patients from an STD clinic and in female prostitutes from two different states of India. A total of 809 sera from Maharashtra and of 61 sera from Goa were analyzed. Of the unscreened sera from Bombay, 39% were positive as were 15% of the sera from Goa. Among the HIV-positive sera from Bombay, 79% were positive for HIV-1, 4% were positive for HIV-2 and 17% were positive for HIV-1 and 2. In the Goa group, 67% of the infected sera were HIV-1-positive and 33% were HIV-2 positive. Due to the nearly even distribution of infections between men and women, a mainly heterosexual mode of transmission is evident. HIV-2 infections were first detected in India in 1990 (Rübsamen et al., Lancet, 1991). Before that time, Asia was believed to be free HIV-2. The present study represents the first documentation of a large proportion of these infections, alone and in combination with HIV-1, in the Asian continent. An HIV-2 epidemic running parallel to an HIV-1 epidemic so far has never been observed outside of Africa. This would indicate that a further spread of HIV-2 worldwide is to be expected and that HIV-2 should be included in programs of vaccine development for humans.