Aim. To assess the trends for the epidemiological situation of chronic hepatitis B monoinfection and chronic hepatitis B+D co-infection in the Kyrgyz Republic for the period of 2010-2012 for the development of anti-epidemic measures depending on the intensity of the process. Methods. The analysis of a database of national reporting forms on the treated cases of chronic viral hepatitis B monoinfection and chronic hepatitis B+D co-infection in primary health care units, cumulated by Republican Medical Information Center of the Ministry of Healthcare of the Kyrgyz Republic for the period of 2010-2012 was performed. Results. The incidence of chronic viral hepatitis D is identical to that of chronic viral hepatitis B (23 and 21 per 100 000 of population respectively) in the Kyrgyz Republic. Over the period of 2010-2012 the high level of total chronic hepatitis B incidence was reported in the northern part of the country (the Issyk-Kul region, 71 per 100 000, and chronic hepatitis D - in the southern part of the country (Osh, 62 per 100 000 of population). Statistically significant increase in the incidence of chronic hepatitis B in almost all regions of the country was recorded whereas only an upward trend was revealed in chronic hepatitis D incidence. Conclusion. Separate registration of patients with chronic viral hepatitis B and D in the Kyrgyz Republic starting from 2010 allowed evaluating the trends for the epidemiological situation of these diseases in different areas and developing preventive and anti-epidemic measures in regions of Kyrgyz Republic.

The prevalence of clinically significant virus mutations in patients with chronic viral hepatitis B from the Kyrgyz Republic was analyzed. Blood plasma samples of 64 patients with verified chronic viral hepatitis B obtained from Kyrgyzstan indigenous people were used in the work. Asymmetric PCR was carried out with extended oligonucleotides and the first reaction amplification product was further used in a new PCR with one of the nested pairs overlapping primers that flanked the entire HBV genome together, followed by sequencing. Based on the phylogenetic analysis of 64 HBV isolates obtained from patients from the Kyrgyz Republic, it was shown that only the genotype D virus was present in the examined group, the HBV subgenotype D1 (68.75%) prevailed compared with the HBV subgenotype D2 (18.75%) and subgenotype D3 (12.5%). For all subgenotypes, several independent infection sources are obvious, subclusters that include isolates from Kyrgyzstan, Kazakhstan and Uzbekistan are distinguished, as well as subclusters that include isolates only from Kyrgyzstan, which are less similar to isolates previously deposited in the international database, which probably indicates an independent HBV homologous evolution in the region. Clinically significant mutations were identified in 26.5% of patients. Including 12.5% with escape mutations that prevent the virus detection and / or allow the virus to replicate despite the vaccine (122K, 128V, 133I, 134N). Another 12.5% of the isolates are characterized by mutations that are independently associated with the liver cirrhosis and hepatocellular carcinoma development, including 21, 24, 27 nucleotides deletions in the Pre-S2 region and the S11F mutation in the PreCore region. In one case, unusual 236S and 250P mutations were found in the positions described as drug resistance sites of the P region associated with the resistance development to adefovir, tenofovir, and entecavir. The hepatitis B virus genetic structure analysis, early virus mutations detection in patients with chronic hepatitis B virus can help to choose the right vaccination strategy, antiviral and immunosuppressive therapy, as well as predict the clinical course and disease progression.

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