Sexually transmitted diseases and sexual behaviour as risk factors for HIV-2 infection in Bissau, Guinea Bissau.

Patients enrolled in a hospital-based case control study (n = 1009) and a follow-up study (n = 130) of HIV-2 infection in Bissau were investigated with regard to sexual behaviour and sexually transmitted diseases (STD). A history of genital ulcer was more frequent in HIV-2 infected male patients (46.4%, 13 out of 28) than in seronegative male patients (17.9%, 7 out of 39) (P = 0.05). Serological evidence of a previous syphilitic infection was significantly related to HIV-2 infection (23%, 12 out of 52, of HIV-2 seropositive patients had a positive Treponema pallidum haemagglutination test compared with 7.1%, 5 out of 70, of seronegative patients, P = 0.025) and was equally frequent in men and women. There was no significant difference in number of non-marital sexual partners and frequency of intercourse between HIV-2 seropositive and seronegative individuals. The seroprevalence of HIV-2 infection was significantly higher among patients with a monogamous marriage, 23.1% (59 out of 255) among males and 31.3% (64 out of 204) among females, than among patients with an officially polygamous marriage, 10.3% (8 out of 77) among males and 11.8% (7 out of 59) among females (P = 0.025 for males and 0.005 for females). Infection-control measures directed at patients with STD should be promoted in Guinea-Bissau. Further research on sexual behaviour and attitudes is needed.