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The paper presents results of avian influenza epidemiological monitoring in the Republic of Crimea in 2019–2020. The attention was focused on the study of water basins of the Azov and Black Seas, the Sivash Lagoon and freshwater lakes in the Feodosia Urban Okrug, Leninsky, Sovetsky, Nizhnegorsky, Chernomorsky and Saksky Raions to detect the avian influenza virus circulation. Examination of the above mentioned areas showed that some freshwater reservoirs became shallow and dry, and aquatic vegetation degraded. The natural biotope analysis conducted in 2019 and 2020 showed a decreased number of semiaquatic wild birds. The pathological material was sampled from semiaquatic and migratory wild birds, as well as from poultry kept in poultry farms and backyards. The collected samples were tested using real-time RT-PCR. In 2019, the AIV type A (H9) genome was detected in one fecal sample taken from wild birds near Kuchuk-Adzhigol Lake in Feodosia Urban Okrug. The AIV type A (H5) genome was detected in 2020 during laboratory testing of pathological material taken from the remains of a mute swan within the shoreline of a freshwater lake near the Ermakovo settlement of the Dzhankoysky Raion. The genetic analysis was performed in the FGBI “ARRIAH” (Vladimir), and the N8 subtype neuraminidase of the influenza virus isolate was determined. The comparative genetic analysis of 258 bp nucleic acid sequences of the AIV H gene fragment showed that the identified isolate belongs to the Asian genetic lineage of highly pathogenic AIV subtype H5 (clade 2.3.4.4) associated with the epidemic spread in Asia, Europe, the Middle East and Africa in 2016–2020.

The paper presents the results of monitoring tests performed in the FGBI “ARRIAH” Branch in 2018 to detect AIV circulation in the Republic of Crimea. As AIVs are most frequently detected in aquatic and semiaquatic birds wild waterfowl present the greatest threat of the disease introduction and spread. That’s why the paper gives special attention to the Azov Sea and Sivash water area and describes natural biotopes of the Central and Eastern Sivash. During expeditions biological material samples were collected, bird species were identified and bird fauna was estimated in waterfowl aggregation sites. Laboratory PCR tests of the biological material collected during the expedition as well from killed birds and poultry revealed no AIV type A. As the number of wildfowl in the their usual aggregation sites decreased due to the fact that fresh water supply through the North-Crimean Canal ceased it can be assumed that the Crimean peninsula will manage to maintain HPAI freedom despite the fact that the disease is being reported close to the peninsula. Nevertheless, the threat of the virus introduction to the commercial and backyard farm stocks still exists as the peninsula is located in the bird migration routes and AI epidemical monitoring is a topical task.