Analysis of the species composition and infection of ticks with pathogens of Lyme disease in the territory of the Republic of Tatarstan for the period 2012–2022

BACKGROUND: The role of ixodid ticks in the transmission of pathogens of a number of natural focal infections can hardly be overestimated. Analysis of the manifestations of the epizootic process is important for planning preventive and anti-epidemic measures and is an integral component of epidemiological surveillance of natural focal infections. AIM: To analyze the species composition of ticks and the infection of ticks with borreliosis pathogens in the Republic of Tatarstan for the period 2012–2022. MATERIALS AND METHODS: An analysis of the species composition of ticks collected by the zoological group of the Center for Hygiene and Epidemiology in the Republic of Tatarstan from environmental objects during the period 2012–2022 was carried out. Testing of the ticks for Borrelia burgdorferi and Borrelia miyamotoi was carried out using the polymerase chain reaction method with hybridization-fluorescent detection. An analysis of statistical observation form No. 2 “Information on infectious and parasitic diseases” (the section “Tick bites”) for the Republic of Tatarstan from 2012 to 2022 was carried out. Statistical processing was performed using descriptive statistics methods in Microsoft Excel. RESULTS: The total number of people who applied for tick bites in the Republic of Tatarstan in 2012–2022 was 77,703, of which 59,168 (76.2%) were people over 18 years of age. During the study period, 5536 ticks were collected for research on the territory of the Republic of Tatarstan from environmental objects. The species composition of ticks was distributed as follows: Dermacentor reticulatus — 75.4%, Ixodes ricinus — 14.1%, Ixodes persulcatus — 10.5%. Infection of different types of ticks with Borrelia was not the same and was 20.4% for I. persulcatus, 14% for I. ricinus, 4.4% for D. reticulatus. In 4 regions of the republic, from ticks of the species I. ricinus pathogenic genomospecies B. miyamotoi were found (the infestation of this type of tick with B. miyamotoi was 0.4%). Indicators of morbidity of the population with ixodid tick-borne borreliosis and indicators of infection rates for ticks vary in different regions of the republic. CONCLUSIONS: The dominant species of ixodid ticks in natural epitopes of the Republic of Tatarstan in 2012–2022 were D. reticulatus (75.4% of the total number of collected ticks). For ticks of this species, the lowest level of infection with Borrelia was demonstrated (4.4% of ticks). This may be one of the factors responsible for the low, in comparison with other regions, incidence rates of tick-borreliosis in the Republic of Tatarstan. The identification of ticks of the species I. ricinus infected with B. miyamotoi confirms the need for targeted molecular genetic and serological examination for recurrent fever in patients with non-erythematous forms of febrile illness after an episode of tick bite.