152 / JofIMAB 2011, vol. 17, book 1 / ABSTRACT Objective: HBV-infection is intermediate-endemic in Bulgaria. There is a trend for decreasing of HBsAg-carrier rate in the last decades, but prevalence remains higher in some specific ethnic communities. Current data regarding high-endemic sources of HBV-infection are limited. Methods: HBsAg and anti-HCV were tested in 677 subjects from a specific ethnical community: 413 adults and 264 adolescents, covered by the National Program for HBV- vaccination of all newborns. Results: Thirty-two of adults (7,7%) were HBsAg- positive. The observed HBsAg-carrier rate was more than three folds higher than general Bulgarian population. In contrast only 2/264 (0.7%) of adolescents were HBsAg- positive. They both were born from HBsAg-positive mothers. Anti-HCV-positive subjects have been found neither among adults nor among adolescents. Conclusion: Our results confirmed existence of separate high-endemic sources of HBV infection in Bulgaria. HBV vaccination program is highly effective even in such specific subgroups and resulted in marked decrease of HBsAg-carrier rate among adolescents. Key words: HBV epidemiology, HBsAg prevalence, ethnical groups, HBV vaccination INTRODUCTION Hepatitis B is intermediate-endemic in Bulgaria, but in the last two decades there is a trend for decreasing of HBsAg carrier rate. This rate was 5.1% in 1987 for blood donors in Sofia and 3.9% for the total population in 1999 (1, 2). In 2007 only 2.2% of blood donors in Sofia were HBsAg-positive (3). The epidemiological data clearly suggested the positive impact of the National Vaccination Program, started in 1991 with mandatory vaccination of all newborns (4). The coverage rate of vaccination in Bulgarian neonates in 1992 and 2001 was 71 % and 93%, respectively (2, 4). One year after the introduction of vaccination against HBV a dramatic decline in the reported annual incidence of acute hepatitis HIGH PREVALENCE OF HBsAg CARRIERS IN A SPECIFIC COMMUNITY IN BULGARIA Zahariy Krastev 1 , Ivan Stoev 2 , Deian Jelev 1 , Aneta Ivanova 1 , Krasimir Antonov 1 , Luydmila Mateva 1 1) Clinic of Gastroenterology, St. Ivan Rilsky University Hospital, Sofia, Bulgaria 2) General Practitioner in village of Ablaniza, Bulgaria Journal of IMAB - Annual Proceeding (Scientific Papers) 2011, vol. 17, book 1 B in infants was seen (4). In addition 10 years after implementation of HBV vaccination program there was a decrease in the incidence of acute hepatitis B cases in all age groups, but the most demonstrative results was found in the age group of 5-14 years (2). Nevertheless, the prevalence of HBsAg carriers still remains higher in some specific ethnic communities compared to general population. Current data regarding high-endemic sources of HBV infection in our country are still limited and the actual impact of implemented total HBV vaccination of all new bourns remains unknown in such specific communities. MATERIALS AND METHODS Prevalence of HBsAg carrier rate was studied in a specific ethnical community of peoples (Bulgarian Mohammedans) living in village of Ablaniza. This place is situated in South-Western part of Bulgaria and was selected for the present study as over the years a number of patients with HBV infection, living in this village, were referred to the Clinic of Gastroenterology, St Ivan Rilsky University Hospital in Sofia for further follow-up and treatment. In January 2011 blood samples were obtained from the inhabitants of Ablaniza who were willing to check their serological status for HBsAg and anti-HCV. No selection of studied population has been performed prior the collection of blood samples. Six hundred and seventy-seven subjects were tested. They were divided in two groups: 413 adults and 264 adolescents. All adolescents were born after 1992, i.e. after implementation of the National Vaccination Program for total HBV vaccination of all newborns. HBsAg and anti- HCV were measured by HBsAg and anti-HCV cassette test (CE, in-vitro diagnostic use). RESULTS Thirty-two out of 413 adult subjects (7.7%) were HBsAg-positive, indicating high endemic prevalence of HBV among inhabitants of studied village. In contrast HBsAg carrier rate was very low (0.7%) among adolescents (fig 1).