НІМФИ КЛІЩІВ ВИДУ IXODES RICINUS, ЇХ ЖИВЛЕННЯ НА ТВАРИНАХ І ЛЮДИНІ ТА ЕПІДЕМІОЛОГІЧНА РОЛЬ

Abstract

Studies show that rodents are only one link in the food chain of the forest mite. J. Anderson [2] points out that in Europe this species attracts more than 300 species of warm-blooded animals and humans. The populational ecology and distribution of certain rodent species are related to the epidemiological situation among humans, mainly in the case of transmission of certain tick-borne pathogens, such as Borrelia burgdorferi sensu lato or tick-borne encephalitis virus (CE). Randolph S. E. [15] and Krebs C. J. [6] point to certain patterns in the biology of Ixodes mites and rodents. In particular, it has been noticed that in the spring the life cycle of mites is dominated by adults that feed on macro-mammals.
 During 2017–2019, larvae, nymphs and adult mites of the Ixodes ricinus were collected from humans and animals and studied in a specialized laboratory of I. Horbachevsky Ternopil National Medical University. During 2017–2021, more than 1,900 specimens of mites were identified and studied. In this article, special attention is paid to the nymphs of this species. This is due to the fact that nymphs feed not only on animals, as in most other Ixodes mites, but also actively attack humans. The analysis of the ratio of nymphs and adults attacking people in the spring-summer and autumn periods of 2017–2019 has been carried out and the peculiarities of their epidemiological condition during the highest activity of ticks have been studied.
 Certain patterns have been established, in particular, the frequency of their attacks on humans compared to adults correlates from 1.16 to 3.55 and is highest in April-May and then in September. The frequency of attacks of different stages of mites is obviously due to the life cycle of this type of mite and the ability to provide itself with food. It is possible that the high number of nymphs in April-May due to the inability to complete its life cycle in autumn, due to the lack of a host-host and the need to overwinter at the larval or nymph stage. Those individuals that manage to complete their life cycle in the fall, overwinter in the adult stage and in the spring they are already active in this life form. The lack of a host can be explained by the factor of a small number of murine rodents, due to which a large number of larvae and nymphs cannot continue their development.
 Analysis of the epidemiological situation showed that in May, the infection with pathogens in nymphs ranges from 33 % to 48 % and in females - from 50 % to 65 %. In June, this indicator decreases significantly, and in September it rises again to 35–56 % in nymphs and 25–38 % in females.