Distribution of HB(s)Ag Subtypes in the World

Abstract

HB(s)Ag subtyping was performed in 5,337 sera from chronic carriers who originated from 54 different countries of the 5 continents. Nine subtypes were defined: ayw(1), ayw(2), ayw(3), ayw(4), ayr, adw(2), adw(4), adr q- and adr q+. The repartition of these subtypes, according to the country of origin of the carriers, enhances the previous results and supplies new data: ayw(1) is prevalent only in Vietnam (51%); ayw(2) in Mediterranean countries (73%); ayw(3) in Greece and Yugoslavia (54%) along with ayw(2) (41%); ayw(4) in West Africa (82%) and Central Africa (42%) along with ayw2; ayr was only found in Vietnam (3.4%); adw(2) is prevalent in North and Central Europe (70%), East and South Africa (95%), India (55%), along with ayw(3) (35%) in northern South America (74%), and in the Antilles (82%); adw(4) is widespread in French Polynesia (45%) - with a 100% frequency in the Marquesas archipelago - as well as in Argentina (42%); adr q- was found only in Oceania: French Polynesia (34%) with a 69% frequency in the Australes, New Caledonia (3 out of 3 HB(s)Ag carriers); adr q+ is the prevalent subtype in South-East Asia if we exclude Vietnam (61%). These results show that a precise geographical distribution of HB(s)Ag subtypes needs more than ‘four main subtypes’ generally used. Enlarging from 4 subtypes to 9 is a requirement for valuable epidemiologic studies, as well as for the specification of anti-HB(s) antibodies produced by hybrids or induced by synthetic peptide. The geographical distribution of these 9 HB(s)Ag subtypes and the serological relationship between some determinants suggest a genetic recombination of viral DNA.