Розповсюдженість кліщів-переносників borrelia burgdorferi в ландшафтно-географічних зонах Чернівецької області

Abstract

The list of human infectious diseases has recently significantly expanded due to new focal infections that are transmitted by the bite of blood-sucking arthropods. Ixodes ticks borrelioses, including Lyme disease, remain the most common naturally occurring transmissible infection in the United States, Europe, and Ukraine in particular. Material and methods. For the last 10 years in Ukraine there has been a tendency to increase the incidence of Lyme disease with an intensive rate from 0.12 in 2000 to 6.45 in 2016. The incidence of Lyme disease in Chernivtsi region during the period under analysis increased by 30 (with an increase in the intensive rate from 0.11% in 2000 to 3.31% in 2016). The purpose of the work was to investigate the prevalence of Ixodes ticks, including positive findings on Borrelia burgdorferi in Chernivtsi region for the period of 2018-2019. Results and discussion. We used the common division of Chernivtsi region into landscape-geographical zones. According to its relief, the territory of Chernivtsi region is divided into a mountain zone (the Bukovynian Carpathians), foothills (Prut-Sirets interfluve) and plain (Prut-Dniester interfluve, forest-steppe zone). We analyzed indicators of the relative number of Ixodes ticks in landscape-geographical areas and the percentage of Ixodes ticks with positive findings, i.e. those that carry the pathogenic Borrelia burgdorferi. Statistical analysis of the obtained data was performed by the method of determining the confidence interval, the level of probability was taken as p≤0.05. The data comparison obtained in 2018 and 2019 showed that during the study period there was a significant increase in the number of ticks that transmit pathogenic Borrelia, in all regions except the mountain zone, especially prominent in the foothills of the Carpathians. Using statistics data, risk of detection was calculated, which is interpreted as the risk of Lyme disease infection when bitten by a tick. When comparing the zones of the foothills of the Carpathians (19.5%) and the Carpathian Mountains (21%) in 2018 the risk of detection was established at 0.92 [0.63-1.36], and in 2019 – the foothills of the Carpathians (41%) and the Carpathian Mountains (15%), respectively, risk of detection equaled 2.7 [1.66-4.41]. The risk of detection of 1.4 [1.66-4.41] was set for both years. When comparing the foothills of the Carpathians (19.5%) and the Forest-Steppe zone (13.5%) in 2018, the risk of detection was 1.44 [1.01-2.06], and in 2019 - the Foothills of the Carpathians (41%) and the Forest-Steppe zone (24%), respectively, risk of detection – 1.56 [1,17-2,09]. The risk of detection of 1.5 [1.2-1.89] was set for both years. During the next stage of the study, we compared the prevalence of Ixodes ticks, which could cause borreliosis, with bacterial contamination of water in the relevant areas. We found a reliable correlation of medium strength between bacterial contamination of water and the percentage of infected ticks – Cramer coefficient was 0.37. Conclusion. Thus, we found an increase in the number of Ixodes ticks, including Borrelia burgdorferi, in Chernivtsi region over the past two years. The risk of infection with borreliosis from Ixodes ticks had a significant increase and extended from the Forest-Steppe zone to the Foothills and the Carpathian Mountains in the period from 2018 till 2019. A significant correlation was found between bacterial water contamination and the percentage of infected Ixodes ticks in Chernivtsi region