Distribution of the hepatitis B surface antigen subtypes in indonesia : implications for ethnic heterogeneity and infection control measures

Previous studies on the distribution of subtypes of hepatitis B surface antigen (HBsAg) in Indonesia have not entirely covered the whole nation. Consequently, we determined the HBsAg subtypes, adw, adr, ayw, and ayr in a total of 569 HBsAg-positive sera from areas so far not studied. With results in this and our previous studies taken together (a total of 3045 HBsAg-positive sera were analyzed), a nationwide picture on the HBsAg subtype distribution indicated that Indonesia could roughly be divided into 4 zones: (i) adw-predominant zone consisting of Sumatera, Java, southern part of Kalimantan, Bali, Lombok, Ternate, and Morotai; (ii) ayw-zone of the eastern part of Nusa Tenggara and Moluccas, (iii) adr-zone of Irian Jaya; and (iv) a mixed subtype-zone of Kalimantan, Sulawesi and Sumbawa. An interesting exception was Padang of Sumatera island: Padang was rich in adr although it is far from the adr-zone. Since the HBsAg subtype, like mutations in mitochondrial DNA, could be used as an ethnological marker, our present results suggest that the peoples in Indonesia have at least three major ethnic origins, represented by adw, ayw, and adr. Of another note, the diagnostic and preventive measures for hepatitis B virus (HBV) infection in Indonesia may be improved by considering such diversity of HBV strains revealed in this study.