title: An epidemiologic study of hepatitis B virus in Bangkok, Thailand.
abstract: Residents of a randomly selected sample of households in a low-income housing project in Bangkok were studied between July 1971 and April 1972. Prevalence of hepatitis B antigen (HBs Ag) in July 1971 was 8.2% in 697 persons age one year and older and changed little with age. Prevalence of antibody to HBs Ag (anti-HBs) was much higher in all age groups and was 46% overall. The prevalence of HBs Ag was higher in males than females from ages 10-29 years and the prevalence of anti-HBs was higher in males up to age 60. The HBV (combined HBs Ag and anti-HBs) age prevalence distribution in July 1971 revealed that over 20% of the children 1-4 years of age had serologic evidence of infection and that the prevalence rose rapidly with age reaching a plateau between 60-70% after age 15. During the nine months of serologic surveillance 13% of individuals acquired either HBs Ag or anti-HBs and 7% lost serologic evidence of HBV infection. The study data suggest that most HBs Ag positive persons are long-term antigen carriers, that their numbers and spatial distribution may be sufficient to account for the wide-spread transmission of HBV in this population, that close person-to-person contact with carriers is probably the most important mode of HBV transmission, and that the susceptibility to becoming an HBs Ag carrier is probably genetically determined.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000032:analysis; D002353:Carrier State / Q000276:immunology / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006509:Hepatitis B / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D006511:Hepatitis B Antigens / Q000302:isolation & purification*; D006801:Humans; D007122:Immunoelectrophoresis; D007223:Infant; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011863:Radioimmunoassay; D012737:Sex Factors; D013785:Thailand
chemical_list: D000914:Antibodies, Viral; D006511:Hepatitis B Antigens