Heterogeneous distribution of hepatitis B serological markers in rural areas of Mexico.

OBJECTIVE To study the distribution of the hepatitis B antibody (anti-HBc) based on a national serosurvey from 10 Mexican states showing a mean HBV prevalence higher than the national one. MATERIALS AND METHODS This was a cross-sectional study. During 2003, anti-HBc was analyzed at INSP in 19 907 sera, and the related sociodemographic factors were determined. RESULTS Anti-HBc prevalence was greater among men, but it was also associated to age, residence in a rural area, low socio-economic status, and illiteracy. Clusters of very high anti-HBc prevalence were found in several rural communities where the prevalence of anti-HBc in adults is 3 to 20 times the national average. CONCLUSIONS Besides a low endemicity of HBV in Mexico, distribution is heterogeneous as was shown in several of the states studied, where there are rural towns with very high prevalence of HBV markers. National serosurveys are useful tools for identifying communities with hepatitis B hyperendemicity, where focused research and control measures are needed.