Incidence of genotype of hepatitis B subvirus and HBsAg subtypes in native people of northern and southeastern Siberia

Serological markers and DNA of hepatitis B virus (HBV) were detected in 487 blood samples of aboriginal people in the Alar district of the Irkutsk region (mostly Buryat) in 2005. HBsAg was found in 40 (8.2%) samples. HBV DNA was found in 24 out of 40 (60%) HBsAg-positive samples. HBV-positive DNA samples were found to contain nucleotide sequences of the Pre-S1, Pre-S2, and S regions of the HBV genome with a total length of 1146 n. 22 out of 24 (92%) isolates were found to belong to the D genotype, two belonged to the C genotype; eight (33.3%) belonged to the D3 subgenotype, six (25.0%) belonged to the D2 subgenotype, one (4.1%) belonged to the D1 subgenotype, and nine (37.5%) belonged to unidentified subgenotype. The incidence of the HBsAg subtype was determined to be ayw2 in 14 out of 24 (58.3%) isolates and ayw3 in seven (29.2%) isolates; the subtype was not identified for one (4.1%) isolate. In two C-genotype isolates, the subtypes were identified as adw2 and adrq+. A comparative analysis of the results of this work and those obtained previously for native people of Yamalo-Nenets Autonomous District (YaNAD, mostly Khanty and Komi) demonstrated significant differences in the incidence in YaNAD of HBsAg (3.2% isolates, p > 0.999), subgenotype D2 (62% isolates, p > 0.95), and subtype ayw3 (70.6% isolates; p > 0.95). The variability in the incidence of two variants in two groups of native Siberian peoples is the evidence of different infection sources in these populations.