Results of cholera monitoring in administrative territories of Russia from 2013 to 2019

Purpose. A dynamic comparative analysis of the results of identification of Vibrio cholerae (V. cholera) isolates from water and human specimens isolated during the monitoring of cholera throughout the Russian Federation in 2013–2019.Materials and methods. Total 385 strains of V. cholerae O1 serogroup (including one toxigenic V. cholerae O1 El Tor Inaba — Rostov region, 2014) and the R-variant from environment objects were identified in the territory of 21 regions of the Russian Federation.Results. It was found that 91% of the strains were isolated in 7 regions of the Russian Federation: Republic of Kalmykia, Krasnodar Krai, Transbaikal Krai, Khabarovsk Krai, Primorsky Krai, Rostov region and Irkutsk region. 2.3% of strains were atypical in their agglutinability, and 75.3% of strains had atypical phagosensitivity. Phagotypes were identified for 13.2% of strains isolated in 11 administrative territories. Phageotype 11 included 48.8% of the strains isolated mainly in the Transbaikal Krai. Non-toxigenic strains of V. cholerae nonО1/nonO139 (n = 46) were isolated from 43 patients with acute intestinal infections and otitis in 8 regions of Russia. PCRtyping of 377 non-toxigenic V. cholerae strains demonstrated that they belong to 13 clusters and 71 genotypes. Strains with unique genotypes (probable cases of importation) and with the same genotypes repeatedly isolated in different years in one or several territories of the Russian Federation were identified, indicating the prevalence of strains in environment throughout the country.Conclusion. The results allowed us to characterize the epidemiological situation of cholera in Russia (in terms of the environment contamination with V. cholerae O1) as unstable, but not significantly changed over the past 7-year period. These data are important for substantiating the forecast for further development of the epidemiological situation.