A serosurvey of Haemophilus ducreyi, syphilis, and herpes simplex virus type 2 and their association with human immunodeficiency virus among female sex workers in Lagos, Nigeria.

BACKGROUND AND OBJECTIVES

To determine the prevalence rates of serological reactivity of Haemophilus (H.) ducreyi, Treponema pallidum, and herpes simplex virus type 2 (HSV-2) antibodies among female sex workers (FSWs) and their association with human immunodeficiency virus (HIV) antibody status.

STUDY DESIGN

Cross-sectional, standard serological assays were used for syphilis, HSV-2 and HIV; a modified enzyme-linked immunosorbent assay (ELISA) was used to detect specific anti-H. ducreyi immunoglobulin (Ig) G and IgA antibodies.

RESULTS

Seroprevalence rates were 86% for anti-H. ducreyi IgG and 69% for anti-H. ducreyi IgA; 4% for rapid plasma reagin (RPR) and Treponema palladium hemagglutination assay (TPHA) confirmed syphilis; 59% for HSV-2; 12% for HIV-1 and 2% for HIV-2. Lower-class FSWs were significantly more likely than upper-class FSWs to be H. ducreyi seropositive (IgG: OR = 42.7; IgA: OR = 7.6) and have current or past syphilis infection (RPR: OR = 3.5; RPR and TPHA: OR = 4.5). The presence of syphilis increased significantly with older age (P-trend < 0.001). Non-Nigerian FSWs had significantly higher reactivity to chancroid (IgG: OR = 3.5; IgA: OR = 1.8) and borderline reactivity to syphilis (RPR: OR = 1.6; TPHA: OR = 2.0). A history of sex with non-Nigerian Africans was significantly associated with chancroid reactivity and borderline significant with syphilis serostatus. H. ducreyi seropositivity was significantly more likely in FSWs with HSV-2 (OR = 2.4) and syphilis (OR = 5.6). Chancroid and HSV-2 antibodies were also more common in HIV-infected FSWs.

CONCLUSION

The prevalence of H. ducreyi antibodies is the highest rate that has been reported. Our findings underscore the importance of an effective program to control GUDs as part of the strategy to prevent the potentially explosive spread of HIV in Nigeria.