Features of Distribution and Spread of Hyalomma marginatum (Acari, Ixodidae) Ticks in the Crimean Hemorrhagic Fever Focus in the Territory of Russia

The review provides the summarized and updated information on the current distribution of the tick Hyalomma marginatum in the natural Crimean hemorrhagic fever (CHF) focus in Russia. The work is based on the analysis of numerous literature sources, as well as the evidence from the personal collecting of ticks during long-term field research. In addition, the collection of ticks of the Stavropol Research Anti-Plague Institute of the Rospotrebnadzor and the database of H. marginatum collections in various regions of southern Russia were used. When delineating the boundaries of the H. marginatum areal and the CHF focus, we also deployed maps of the epidemiological survey of the focus, weekly and annual final reports on the CHF incidence from the Rospotrebnadzor Administrations. H. marginatum inhabits all regions of the Southern Federal District and the North-Caucasian Federal District, as well as the Crimean Peninsula and the south of the Saratov Region. The northern border of the areal reaches the Lugansk People’s Republic, Rostov, Volgograd, and Saratov Regions. H. marginatum is widely disseminated in the territory of Kalmykia and the Astrakhan Region. In the North Caucasus, it inhabits the entire flatland up to the foothills of the Greater Caucasus. The tick is widely distributed in the Stavropol Territory, populating the entire region. In the mountainous part of the Krasnodar Territory, this species is absent, but common in the rest of the areas. Beyond that, it is found on the Black Sea coast. In Karachay-Cherkessia, Kabardino-Balkaria, North Ossetia and Ingushetia, the tick lives in the northern steppe regions of the republics, in some places it invades the foothills. In Chechnya and Dagestan, the species widely inhabits the steppes and semi-deserts of the Terek-Kuma Interfluve. Moreover, in Dagestan, H. marginatum lives across the plain and foothill territory of the republic and even reaches the highlands up to a height of more than 2000 m above sea level. In addition, it is widely disseminated on the Crimean peninsula, both the flatland and the mountainous part.