MOLECULAR-EPIDEMIOLOGICAL FEATURES OF HEPATITIS B VIRUS

Abstract

Abstract. Hepatitis B virus is a serious issue of public health services all over the world, particularly in Russia and its regions. The cause can be determined due to its higher incidence rate in different ethnic and geographical groups, variety of manifestation of clinical forms as well as outcomes. According to WHO data, about 50 million people in the world are annually infected with hepatitis B virus. Development of molecular-genetic methods of research has allowed to expand representations about the activator biology. Genetic variability of hepatitis B virus genome has been subject to identification of 10 various geographically widespread genotypes designated by letters from A to J. In a number of genotypes subgenotypes differing from one another on 4–8% full genome sequences are revealed. In the work a table of geographical prevalence of various genotypes of hepatitis B virus in the world is presented. The geographic distribution of genotypes of hepatitis B virus is closely connected with endemic regions and indigenous population, living there. So the genotypes B and C are connected with the population of Asian countries, genotypes A and D are extended among European countries and in the USA. The genotype D is considered to be a prevailing type among patients with hepatitis B in several regions of Turkey. The phylogenetic analysis of nucleotide sequences of hepatitis B virus isolates in African regions has shown presence of three subgenotypes — А1, А2, А3. In the countries of Asia the following six subgenotypes B are noted: В1 in Japan, В2–В5 and В7 in East Asia Subgenotip B6 is found among indigenous population living in the Arctic regions, including Alaska, northern Canada and Greenland. The genotype C has five serotypes (С1–С5) which are extended in East and South East Asia. The genotype D, also has five subgenotypes (D1–D5) which are extended in Africa, India, the Mediterranean region, Europe. Genotype F has four subgenotypes (F1– F4) which circulate in Central and the South America. Subgenotypes are not revealed among genotypes E, G, H, I and J. In the territory of the Russian Federation the highest incidence of hepatitis B virus is noted in 3 genotypes (A, C, D). Among them the genotype D comprising 88% of them is the prevailing one.

Keywords

• hepatitis b virus
• molecular epidemiology
• genotypes
• subgenotypes
• virus loading
• mutations