Markers of Viral Hepatitis B in Blood–Plasma Samples of the Indigenous Population of the Far North of Russia. HBV Genotypes and HBsAg Subtypes

Hepatitis B is a major public health problem worldwide. The indigenous population of remote regions with harsh living conditions, such as the Far North of Russia, with possibly unique genetic mutations in the local strains of this pathogen, remains poorly studied. The aim of the study was to determine the prevalence of serological HBV markers in blood–plasma samples of the population of the Far North of Russia and to determine HBV genotypes and HBsAg subtypes in blood–plasma samples containing HBsAg. We studied 702 blood–plasma samples taken from the indigenous population (Tundra Nenets) of the village of Gyda in the Tazovsky district of the Yamalo-Nenets autonomous okrug (YaNAO) (north of the Gydan Peninsula). Detection of serological HBV markers—HBsAg, anti-HBs, and anti-Hbcore—was carried out using JSC Vector-Best reagent kits. HBV genotypes and HBsAg subtypes in the samples were determined according to our own original procedure with monoclonal antibodies and by classical molecular-biological methods. The prevalence of HBsAg in the entire sample was 0.4% (3/702). For the subgroup of samples (persons older than 15 years during the first two expeditions, 300 samples), an extended analysis of the markers was carried out. The following frequencies were determined for them: HBsAg, 0.7% (2/300); anti-HBs, 63.7% (191/300); and anti-HBcore, 11.3% (34/300). HBV statuses were established for this subgroup: the presence of HBV infection (0.7%), past hepatitis B infection (9.3%), and immunity as result of vaccination (54.3%). Genotype D was established for two samples containing HBsAg (subtypes ayw2 and ayw3); the results of the two used methods coincided. The prevalence of HBsAg in the Tazovsky and adjacent Purovsky districts (the main population being Nenets, previously published data) differed (0.4% vs. 1.7%, p < 0.05), presumably due to vaccination (samples of the Purovsky district were collected almost 20 years earlier), as well as the distribution of HBV genotypes. The Tazovsky district of YaNAO is now a low endemic region in terms of HBV infection. The HBV isolates belong to the most common HBV genotype D in the Russian Federation (HBsAg subtypes ayw2, ayw3).