Department of Eco-Epidemiology of Parasitic Diseases, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.
Department of Pathology and Veterinary Diagnostics, Warsaw University of Life Sciences- SGGW, 159c Nowoursynowska Street, 02-766, Warsaw, Poland.
Parasit Vectors. 2021 May 20;14(1):267. doi: 10.1186/s13071-021-04758-7.
The significance of tick-borne diseases has increased considerably in recent years. Because of the unique distribution of the tick species Dermacentor reticulatus in Poland, comprising two expanding populations, Eastern and Western that are separated by a Dermacentor-free zone, it is important to conduct studies on the process of tick expansion and emergence of canine babesiosis. The main aim of the current study was to monitor the expansion of D. reticulatus populations from spring 2016 to autumn 2018 to determine (1) the actual geographical range of this tick species, and (2) and the seasonal/annual shift in range limits and changes in distance between Western and Eastern populations of ticks (the size of the non-endemic area).
Ticks were collected in spring/autumn during a 3-year study. From each season and year at least three pairs of sites from the Western and Eastern populations were selected. Then the mean distance between paired sites was calculated for each season and year. We collected and analyzed data from veterinary clinics on the number of canine babesiosis cases treated in the clinic during a whole year (2018).
Accordingly, further expansion of the two D. reticulatus populations was recorded, mainly along river basins. Marked colonization of the gap zone was observed, with a mean annual shift in the range of 2.5-10 km and a steadily decreasing distance between the two tick populations. The occurrence of babesiosis in different regions revealed low numbers of cases in Western Poland (19 cases/year) and the gap area (only 7 cases/year) and high incidence (up to 250 cases/1000 dogs) and fatality (total 3.65%) in Central and Eastern Poland. Strong associations were found geographically between tick and babesiosis occurrence and temporally in the seasonal patterns of occurrence of ticks and outbreaks of babesiosis.
We documented the shift in range limits and continued process of colonization of the gap zone accompanied by the emergence of canine babesiosis in the Eastern expansion zone. Updated maps of the distribution of ticks and occurrence of babesiosis in different regions of Poland have allowed us to predict of the emergence of pathogens vectored by D. reticulatus. Incidence (per 1000 dogs) of canine babesiosis in veterinary clinics by current range of D. reticulatus.
近年来，蜱传疾病的意义显著增加。由于波兰的硬蜱 Dermacentor reticulatus 物种的独特分布，包括两个不断扩大的种群，东部种群和西部种群，它们被一个无硬蜱的区域隔开，因此对蜱的扩张和犬巴贝斯虫病的出现过程进行研究非常重要。目前研究的主要目的是监测 Dermacentor reticulatus 种群从 2016 年春季到 2018 年秋季的扩张情况，以确定：（1）该蜱种的实际地理范围；（2）和范围极限的季节性/年度变化以及蜱东部种群和西部种群之间的距离变化（非疫区的大小）。
在 3 年的研究中，于春季/秋季采集蜱虫。每年每个季节至少从东部种群和西部种群中选择三对采样点。然后计算每个季节和每年的配对采样点之间的平均距离。我们从兽医诊所收集并分析了 2018 年全年治疗犬巴贝斯虫病的病例数量数据。
因此，记录到了两个 Dermacentor reticulatus 种群的进一步扩张，主要沿河流流域。观察到明显的隔离带殖民化现象，范围平均每年转移 2.5-10 公里，两个蜱种群之间的距离稳步减小。不同地区巴贝斯虫病的发生情况显示，波兰西部（每年 19 例）和隔离带地区（每年仅 7 例）的病例数量较少，而波兰中部和东部的发病率（高达 250 例/1000 只狗）和死亡率（总死亡率 3.65%）较高。蜱和巴贝斯虫病的发生在地理上存在很强的相关性，并且在蜱虫发生的季节性模式和巴贝斯虫病的爆发之间存在时间上的相关性。
我们记录了范围极限的变化和隔离带的持续殖民化过程，同时伴随着犬巴贝斯虫病在东部扩张区的出现。波兰不同地区的蜱虫分布和巴贝斯虫病发生情况的最新地图，使我们能够预测由 Dermacentor reticulatus 传播的病原体的出现。目前 Dermacentor reticulatus 分布范围的兽医诊所犬巴贝斯虫病的发病率（每 1000 只狗）。
