New natural variants of hepatitis B virus among Amerindians from Argentina with mainly occult infections.

Background: Hepatitis B virus infection is frequent among Amerindians. In Argentina HBV genotypes A, B, C, D, E, F and H were described in different populations, while some cases of occult hepatitis B infection (OBI) were reported in human immunodeficiency virus (HIV) coinfected patients.

Objective: To determine the prevalence, genetic diversity of HBV and to analyze the deduced amino acid sequence of both S and viral polymerase (P) genes among Amerindians of Argentina.