Background 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). Methods 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). Results 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. Conclusions 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. Graphic Abstract

BackgroundTick-borne infections are no longer confined to rural areas, they are documented with increasing frequency in urban settlements across the world. They are known to cause diseases in humans as well as in their companion animals.MethodsDuring a period of 2 years, from January 2013 until December 2014, ticks were collected from dogs and cats in 18 veterinary clinics in the Wrocław Agglomeration, Poland. In total, 1455 ticks were found on 931 pets: 760 domestic dogs and 171 cats. For molecular examinations 127 I. ricinus ticks (115 females and 12 males) were randomly selected, all collected I. hexagonus (n = 137, 32 females, 98 nymphs, 7 larvae) and all collected D. reticulatus (n = 46, 31 females, 15 males) were taken. Ixodes ricinus and I. hexagonus ticks were tested for Rickettsia spp., Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis and Babesia spp., while D. reticulatus ticks were investigated for Rickettsia spp. and Babesia spp. only.ResultsIn total, 65.4 % I. ricinus ticks were infected with at least one pathogen. Over 50 % of I. ricinus were positive for Rickettsia spp. (R. helvetica and R. monacensis). The infection level with A. phagocytophilum was 21.3 %. DNA of Cand. N. mikurensis was detected in 8.1 % I. ricinus ticks. Interestingly only female ticks were infected. The prevalence of Babesia spp. was confirmed in 9.0 % of I. ricinus involving the species B. microti and B. venatorum. A total of nineteen double, one triple and two quadruple infections were found in I. ricinus ticks only. Almost 11 % of I. hexagonus ticks were positive for at least one of the tested pathogens. Rickettsia spp. infection was found in 2.2 %, while A. phagocytophilum was detected in 8.1 % of I. hexagonus ticks. Only one nymph was positive for Cand. N. mikurensis and none of I. hexagonus ticks harbored a Babesia spp. Over 60 % of D. reticulatus ticks were positive for rickettsial DNA, exclusively belonging to the species R. raoultii.ConclusionThe high tick infestation rates and the prevalence of pathogens found in these ticks demonstrate a serious level of encounter to tick-borne diseases in urban dogs in the Wroclaw area, and provide evidence that dogs and cats themselves may substantially contribute to the circulation of the ticks and pathogens in the urban area.

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Tick-borne encephalitis virus (TBEV) is the most important tick-transmitted arbovirus causing human disease in Europe, but information on its endemic occurrence varies between countries because of differences in surveillance systems. Objective data are necessary to ascertain the disease risk for vaccination recommendations and other public health interventions. In two independent, separately planned projects, we used real-time RT-PCR to detect TBE virus in questing ticks. In Poland, 32 sampling sites were selected in 10 administrative districts located in regions where sporadic TBE cases were reported. In Germany, 18 sampling sites were selected in two districts located in a region with high TBE incidence. Altogether, >16,000 ticks were tested by real-time RT-PCR, with no sample testing positive for TBEV. A systematic search for published studies on TBEV prevalence in ticks in Poland and Germany also suggested that testing large numbers of collected ticks could not consistently assure virus detection in known endemic foci. Although assignment of results to administrative regions is essential for TBE risk mapping, this was possible in only 10 (investigating 22,417 ticks) of 15 published studies (>50,000 ticks) identified. We conclude that the collection and screening of ticks by real-time RT-PCR cannot be recommended for assessment of human TBE risk. Alternative methods of environmental TBEV monitoring should be considered, such as serological monitoring of rodents or other wildlife.

ABSTRACT:The relationship between climate data and tick questing activity is crucial for estimation of the spatial and temporal distribution of the risk of ticks and tick-borne diseases. This study establishes correlations between selected meteorological variables provided by the Weather Research and Forecasting model (WRF) and the questing activity of Ixodes ricinus nymphs and adults on a regional scale across Lower Silesia, Poland. Application of Generalized Linear Mixed Models (GLMM), built separately for adults and nymphs, showed that solar radiation, air temperature, and saturation deficit appeared to be the meteorological variables of prime importance, whereas the wind speed was less important. However, the effect of meteorological parameters was different for adults and nymphs. The adults are also more influenced by forest cover and the percentage of forest type if compared to nymphs. The WRF model providing meteorological variables separately for each location and day of tick sampling can be useful in studies of questing activity of ticks on a regional scale. Journal of Vector Ecology 39 (1): 138-145. 2014.