Differences in the prevalence of hepatitis B antigen and antibody among Panamanian Indian populations.

Abstract

Counterelectrophoresis was used for testing of 1,623 sera from individuals from Panama's three major Indian tribes for hepatitis B antigen (HB Ag). A random subsample from each group was tested for antibody to HB Ag (HB Ab) by the radioimmunoprecipitation technique. HB Ag was significantly more prevalent among the Guaymi than among either Choco or Cuna Indians, but prevalence of both HB Ag and HB Ab among the Guaymi varied by village. The Chocó had a greater frequency of HB Ab in every age group than the Guaymi, indicating that although Chocó were more intensively exposed to HB Ag than Guaymi, fewer became chronically antigenemic. Using the prevalences of HB Ag and HB Ab, we calculated the percentage of infected individuals who remained chronically antigenemic and found it to be significantly higher among younger people.