title: [Prevalence of HBsAg].
mesh_terms: D000818:Animals; D002353:Carrier State / Q000635:transmission; D002681:China; D004199:Disease Vectors; D006509:Hepatitis B / Q000635:transmission*; D006514:Hepatitis B Surface Antigens / Q000032:analysis*; D006801:Humans
chemical_list: D006514:Hepatitis B Surface Antigens