SEXUAL TRANSMISSION OF HEPATITIS-B IN MWANZA, TANZANIA

Background: Hepatitis B virus (HBV) is endemic and poses a grave publi c health problem in Africa where it is mainly transmitted from mother to baby or during childhood, Sexual transmission has also been suggest ed to play a role in East Africa, but this has never been properly dem onstrated. Additional preventive strategies may be proposed if sexual transmission of HBV occurred in this region where HIV and other STDs a re highly prevalent. Goals: To determine the prevalence of markers for hepatitis B virus (HBV) and other sexually transmitted diseases (STD) in routine blood samples taken from three populations in Mwanza, Tanz ania, and to use the data collected to look at the association between hepatitis B and other STDs, including human immunodeficiency virus (H IV). Study Design: Routine blood samples were collected from 1,025 pat ients attending a clinic for STDs, 253 voluntary blood donors from sec ondary schools, and 952 blood donors who gave blood in a hospital spec ifically for a relative who needed a blood transfusion, All samples we re tested for HIV by double enzyme-linked immunosorbent assay (ELISA), and for syphilis using the Treponema pallidum hemagglutination (TPHA) and rapid plasma reagin (RPR) tests. Two markers for HBV were examine d by the double ELISA method, the presence of the anti-hepatitis B cor e antigen (anti-HBc) and the hepatitis B surface antigen (HBsAg). Resu lts: There were high prevalences of HBV, syphilis, and HIV in relative donors and STD patients, Although HBV markers were more prevalent in men of increasing ages, syphilis and HIV markers were more prevalent i n young women, Evidence of past infection with HBV (presence of anti-H Bc) was associated with serologic markers of recent treponemal infecti on (both TPHA and RPR positive) in both sexes (men odds ratio [OR] = 1 .91, P < 0.011; women OR = 2.34, P < 0.02) and with HIV in men (OR = 1 .93, P < 0.003), Current infection with HBV (presence of HBsAg) was as sociated with recent syphilis in men (OR = 2.13, P < 0.006), In STD pa tients, current infection with HBV was associated with Trichomonas vag inalis in women (OR = 3.57, P < 0.002) and recent syphilis in men (OR = 3.46, P < 0.001), There was no further association between HBV marke rs and any other STD pathogen or any particular STD syndrome, nor was there any association between current HBV infection and HIV in both se xes, The population attributable fraction for sexual acquisition gf he patitis B is estimated at 7.2% in men and 3.0% in in women, based on t he association between hepatitis B and syphilis. Conclusions: These fi ndings suggest that sexual acquisition of hepatitis B occurs at low le vels in Mwanza, and that HBV can be prevented through enhancement of t he current HIV/STD control activities, in addition to improved vaccina tion strategies.