BACKGROUND: In many parts of the world, sexual transmission of hepatitis B virus plays a major role in acquisition of infections. In Northeast region of Iran the prevalence rate and risk factors influencing this type of transmission was not investigated. Therefore, the concurrence of hepatitis B virus (HBV) and STDs was studied to determine the prevalence and risk factors of sexual transmission of hepatitis B virus. MATERIAL/METHODS: This study was carried out among 1500 attendances to the laboratories for STDs examination between 1998 and 2000. Those who were positive for STDs (syphilis & gonorrhea) were examined for HBV infection by determination of hepatitis B surface antigen (HBsAg). The data was analyzed and compared to the normal population. RESULTS: The prevalence of STD in this population was 4.66% for syphilis and 6% for gonorrhea. Among this population the seroprevalence of HBsAg was 10% in women and 14.2% in men (mean seroprevalence of HBsAg was 13.13%). The concurrence of hepatitis B virus and syphilis was 14.28% which was slightly higher than concurrence for gonorrhea (12.22%). CONCLUSIONS: The prevalence of HBV in our patient population was high, exceeding the national estimates. This population also represents a high-risk group in Northeast of Iran. Further, our data indicates that such high prevalence is significantly more evident in patients with low socioeconomic status.

Keywords: Gonorrhea - epidemiology, Hepatitis B Surface Antigens - blood, Hepatitis B virus - immunology, Iran - epidemiology, Syphilis - epidemiology