title: Primary hepatitis A virus infection in developing countries: decline of maternal antibodies and time of infection.
abstract: In developing countries, HAV seems to be responsible for a widespread, inapparent and protective infection during early childhood. This report emphasizes early infection and its relationship to protection by passive immunity from maternal antibody in a highly endemic area such as Somalia. Our result show that HAV infection in Somalia primarily occurs during the first 4 years of life (4 months to 4 years). Cases are infrequent in the first 3 months due to passive immunity secondary to maternal antibody (cord-blood and colostrum anti-HAV). As the level of protection declines, the rate of acute infection rises as determined by the presence of IgM-specific anti-HAV.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006506:Hepatitis A / Q000453:epidemiology / Q000276:immunology*; D006507:Hepatovirus / Q000276:immunology*; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007075:Immunoglobulin M / Q000032:analysis*; D007223:Infant; D008297:Male; D008875:Middle Aged; D012998:Somalia
chemical_list: D007075:Immunoglobulin M