Tick-borne encephalitis

 Over the next quarter of a century, its wide distribution was established from the eastern to the western borders of Russia - from Primorye to Karelia. The area of ​​tick-borne encephalitis coincides with the area of ​​distribution of ixodid ticks I. persulcatus and I. ricinus, whose habitats are primarily southern taiga dark coniferous, subtaiga coniferous-broad-leaved and coniferous-small-leaved forests, and to a lesser extent middle taiga forests.

The incidence of tick-borne encephalitis is subject to certain fluctuations, which is associated with several factors - fluctuations in the number of ticks, the implementation of preventive measures, the intensity of visits by the population to forest lands during periods of the highest numbers of ixodid ticks (spring, early summer).

One of the features of the incidence of tick-borne encephalitis is that the most intense natural foci of this infection (a very high number of ixodid ticks and their high virality) are located in the south of the Far East, where this disease was first discovered and where high morbidity with high mortality was observed. Vigorous preventive measures and the alertness of the population regarding tick-borne encephalitis have led to the fact that a relatively low incidence has been observed there for a long time. In 1996, 163 people fell ill in the Primorsky Territory (7.3 per 100 thousand) and in the Khabarovsk Territory - 96 people (6.1). The most cases in 1996 were in the Republic of Udmurtia (incidence rate - 60.0 per 100 thousand people), in Tomsk (54.5); Kurgan (44.3) and Perm (41.7) regions. The following group of regions with high and increased incidence: Sverdlovsk (39.9), Tyumen (35.5) regions, Krasnoyarsk Territory (28.8), Chelyabinsk region (18.6), the Republics of Khakassia (16.5) and Altai (16.4), Kemerovo (14.6) and Novosibirsk (14.5) regions.

Another feature of the incidence of tick-borne encephalitis in recent years is the predominance among sick city residents. Among the patients, up to 75% are city residents who became infected in suburban forests, gardens and vegetable plots. One of the main reasons for the epidemiological problems with tick-borne encephalitis in recent years, primarily in the regions of the Urals and Western Siberia, is the complete cessation of acaricidal treatments of the territory due to the ban on the use of DDT dust and the reduction in the scale of seroprophylaxis due to the lack of specific immunoglobulin. The complex scheme of vaccine prevention and its insufficient effectiveness make it difficult to carry it out widely, especially in cities. Currently, the main measure for the prevention of tick-borne encephalitis is sanitary and educational work among the population to explain measures of individual protection against attacks by ixodid ticks.

Prokhorov B.B. 1998