Katarzyna Tołkacz

Parasite infections in wildlife vary across time and space due to interactions among host biology, ecological processes, and climatic variability. Under ongoing climate change, understanding how temperature, precipitation, or humidity influences parasite dynamics is important for predicting shifts in infection patterns and host-parasite interactions. Here, we examine how variation in climatic conditions is associated with helminth infections in a free-living rodent, the bank vole ( Myodes glareolus ), across 17 years and multiple spatial scales. Using zero-inflated generalised linear models, we quantified the effects of climatic variables on individual parasite burden. Climatic conditions (temperature and humidity or precipitation) affected helminth infections across all analysed scales, though the strength and direction of these effects differed among parasite species and between temporal and spatial scales. In the temporal dataset, parasite load was associated with seasonal variation in weather conditions, whereas in the spatial datasets, infection levels were linked to yearly average climatic variables. The differences reflect species-specific parasites’ life histories and transmission strategies. Our findings highlight the importance of analysing individual parasite species rather than overall parasite load or aggregated infection indices when assessing the impacts of climatic variation on host-parasite dynamics.

Rodents serve as hosts for many species of parasites, including cestodes, but the taxonomy of rodent-infecting tapeworms, especially in Central Europe, is still understudied. Therefore, the current study was conducted to identify larval and adult cestodes in free-living rodents from Northeastern Poland. The fieldwork was conducted between 2014 and 2023 in three forest sites. Cestodes were collected from five rodent species ( Clethrionomys glareolus, Alexandromys oeconomus , Microtus agrestis, Apodemus agrarius and A. flavicollis , and were identified through morphology and by several genetic markers (12S rDNA, cox1, nad 1 , 28S rDNA , 12S-16S rDNA) using phylogenetic analyses. A total of 58 cestode specimens were analyzed using molecular and phylogenetic analyses. Species identified included Catenotaenia henttoneni, Spasskijela kratochvili, Mesocestoides litteratus, Mesocestoides melesi , and others. Three Paranoplocephala specimens were identified as P. kalelai based on nad1 sequences. Morphological and genetic analyses indicated that the dominant adult cestode in bank vole was C. henttoneni and Mesocestoides spp. were the dominant larval cestodes. This study combined genetic and morphological methods to identify the cestodes infecting rodents in Poland. It confirmed the existence of P. kalelai in Poland, suggesting that previously reported Paranoplocephala spp., identified by morphological characters, may have corresponded to this molecularly identified species. Our study also highlighted gaps in genetic databases that currently still do not allow precise species identification.

We assessed the diet composition of wolves inhabiting Notecka Forest (ca 1400 km ² ) in western Poland based on the analysis of scats (n = 261) collected in 2008–2021. The study revealed that wolves in this large forest tract, consisting mainly of pine monocultures, consumed primarily wild ungulates (95.2% of consumed biomass). The roe deer was the essential food item (47.8%), followed by the red deer Cervus elaphus (25.1%) and the wild boar Sus scrofa ) (18.4%). Wolves supplemented their diet with medium‐sized wild mammals, mainly the European hare Lepus europaeus (2.8%) and the Eurasian beaver Castor fiber (1.9%). The food niche was narrow ( B = 1.1), and there was no difference in food composition between the spring–summer and autumn–winter seasons. We emphasize the significance of the smallest European wild ruminant, roe deer, in the diet of wolves inhabiting Central European Plains.

Background: Canine hepatozoonosis caused by Hepatozoon canis is a common infection in dogs, with frequent case reports from the Mediterranean region and more recently from several Central European countries, such as Hungary and Germany. Despite the high prevalence of H. canis in red foxes, no infections have been reported to date in dogs in Poland. We describe here the first autochthonous cases of H. canis infection in dogs, including their clinical features, and report the prevalence of H. canis in grey wolves from different regions of Poland. Methods: Thin smears prepared from blood samples collected from dogs were evaluated by microscopic examination. A total of 60 wolves and 47 dogs were tested. Infections were confirmed by PCR and sequencing. Results: Gamonts of H. canis were found in > 50% of the neutrophils of two dogs and in < 10% of the neutrophils in another five dogs. Molecular typing by PCR sequencing of the 18S ribosomal RNA gene fragment confirmed infections in 11 dogs from different regions of Poland, in 2.7% of dogs attending veterinary practices in central Poland and in 35% of wolves from various geographical regions of Poland. Clinical features manifested mostly in older dogs, and the most common signs were anaemia and apathy. Young dogs usually remained asymptomatic. Conclusions: This is the first report of H. canis infection in dogs and wolves in Poland. Although the exact vector of the parasite is not known, veterinary practitioners should be aware of this new parasitosis and should consider appropriate diagnostics to confirm/exclude this infection. Further studies are needed to understand the transmission routes of H. canis in domestic and wild canids in Poland. Graphical

Dirofilaria repensis an expanding vector-borne zoonotic parasite of canines and other carnivores. Sub-clinically infected dogs constitute the most important reservoir of the parasite and the source of infection for its mosquito vectors. However, occurrence ofD. repensinfection in wild animals may contribute to the transmission of the parasite to humans and may explain the endemicity of filariae in newly invaded regions. The aim of the current study was to determine the occurrence ofD. repensin 511 blood and spleen samples from seven species of wild carnivores (wolves, red foxes, Eurasian badgers, raccoons, raccoon dogs, stone martens, and pine martens) from different regions of Poland by means of a PCR protocol targeting the 12S rDNA gene.Dirofilaria repens–positive hosts were identified in seven of fourteen voivodeships in four of the seven regions of Poland: Masovia, Lesser Poland, Pomerania and Warmia-Masuria. The highest prevalence was found in Masovia region (8%), coinciding with the highest previously recorded prevalence in dogs in Central Poland. The DNA ofDirofilariawas detected in 16 samples of three species (total prevalence 3.13%). A low and similar percentage of positive samples (1.9%, 4.2% and 4.8%) was recorded among badgers, red foxes, and wolves, respectively.Dirofilaria repens–positive hosts were identified in seven of fourteen voivodships. Based on detection in different voivodeships,D. repens–positive animals were recorded in four out of the seven regions of Poland: in Masovia, Lesser Poland, Pomerania, and Warmia-Masuria. The highest prevalence of filariae was found in Masovia region (8%), reflecting the highest previously recorded prevalence in dogs (12–50%) in Central Poland. In summary, we conducted the first comprehensive study on the epidemiology ofD. repensin seven species of wild hosts in all seven regions of Poland and identified the first case ofD. repensinfection in Eurasian badgers in Poland and the second in Europe.

Candidatus Neoehrlichia mikurensis (CNM) and Hepatozoon spp. are important vector-borne parasites of humans and animals. CNM is a relatively recently discovered pathogen of humans. Hepatozoon are parasites of reptiles, amphibians and mammals, commonly found in rodents and carnivores worldwide. The present study aimed to determine the prevalence of CNM and Hepatozoon spp. in three species of Microtus and to assess the occurrence of vertical transmission in naturally-infected voles. Molecular techniques were used to detect pathogen DNA in blood and tissue samples of captured voles and their offspring. The prevalence of CNM in the vole community ranged 24–47% depending on Microtus species. The DNA of CNM was detected in 21% of pups from three litters of six infected Microtus dams (two Microtus arvalis and one M. oeconomus) and in 3/45 embryos (6.6%) from two litters of eight CNM-infected pregnant females. We detected Hepatozoon infection in 14% of M. arvalis and 9% of M. oeconomus voles. Hepatozoon sp. DNA was detected in 48.7% of pups from seven litters (6 M. arvalis and 1 M. oeconomus) and in two embryos (14.3%) obtained from one M. arvalis litter. The high prevalence of CNM infections in the Microtus spp. community may be a result of a relatively high rate of vertical transmission among naturally infected voles. Vertical transmission was also demonstrated for Hepatozoon sp. in M. arvalis and M. oeconomus. Our study underlines the significance of alternative routes of transmission of important vector-borne pathogens.

There is now considerable evidence that in Europe, babesiosis is an emerging infectious disease, with some of the causative species spreading as a consequence of the increasing range of their tick vector hosts. In this review, we summarize both the historic records and recent findings on the occurrence and incidence of babesiosis in 20 European countries located in southeastern Europe (Bosnia and Herzegovina, Croatia, and Serbia), central Europe (Austria, the Czech Republic, Germany, Hungary, Luxembourg, Poland, Slovakia, Slovenia, and Switzerland), and northern and northeastern Europe (Lithuania, Latvia, Estonia, Iceland, Denmark, Finland, Sweden, and Norway), identified in humans and selected species of domesticated animals (cats, dogs, horses, and cattle). Recorded cases of human babesiosis are still rare, but their number is expected to rise in the coming years. This is because of the widespread and longer seasonal activity of Ixodes ricinus as a result of climate change and because of the more extensive use of better molecular diagnostic methods. Bovine babesiosis has a re-emerging potential because of the likely loss of herd immunity, while canine babesiosis is rapidly expanding in central and northeastern Europe, its occurrence correlating with the rapid, successful expansion of the ornate dog tick (Dermacentor reticulatus) populations in Europe. Taken together, our analysis of the available reports shows clear evidence of an increasing annual incidence of babesiosis across Europe in both humans and animals that is changing in line with similar increases in the incidence of other tick-borne diseases. This situation is of major concern, and we recommend more extensive and frequent, standardized monitoring using a “One Health” approach.

Toxoplasma gondii is an intracellular Apicomplexan parasite with a broad range of intermediate hosts, including humans and rodents. Rodents are considered to be reservoirs of infection for their predators, including cats, felids, pigs, and wild boars. We conducted a multi-site, long-term study on T. gondii in northeastern Poland. The study aimed to monitor the seroprevalence of T. gondii in the four abundant vole species found in the region (Myodes glareolus, Microtus arvalis, Microtus agrestis, and Alexandromys oeconomus) and to assess the influence of both extrinsic (year of study and study site) and intrinsic (host sex and host age) factors on seroprevalence. A bespoke enzyme-linked immunosorbent assay was used to detect antibodies against T. gondii. We examined 577 rodent individuals and detected T. gondii antibodies in the sera of all four rodent species with an overall seroprevalence of 5.5% [4.2–7.3] (3.6% [2.6–4.9] for M. glareolus and 20% [12–30.9] for M. arvalis, M. agrestis, and A. oeconomus). Seroprevalence in bank voles varied significantly between host age and sex. Seroprevalence increased with host age and was higher in females than males. These results contribute to our understanding of the distribution and abundance of T. gondii in voles in Poland and confirm that T. gondii also circulates in M. glareolus and M. arvalis, M. agrestis and A. oeconomus. Therefore, they may potentially play a role as reservoirs of this parasite in the sylvatic environment.

Background: Protozoa in the genus Babesia are transmitted to humans through tick bites and cause babesiosis, a malaria-like illness. Vertical transmission of Babesia spp. has been reported in mammals; however, the exact timing and mechanisms involved are not currently known. The aims of this study were to evaluate the success of vertical transmission of B. microti in female mice infected before pregnancy (mated during the acute or chronic phases of Babesia infection) and that of pregnant mice infected during early and advanced pregnancy; to evaluate the possible influence of pregnancy on the course of parasite infections (parasitaemia); and to assess pathological changes induced by parasitic infection. Methods: The first set of experiments involved two groups of female mice infected with B. microti before mating, and inseminated on the 7th day and after the 40th day post infection. A second set of experiments involved female mice infected with B. microti during pregnancy, on the 4th and 12th days of pregnancy. Blood smears and PCR targeting the 559 bp 18S rRNA gene fragment were used for the detection of B. microti. Pathology was assessed histologically. Results: Successful development of pregnancy was recorded only in females mated during the chronic phase of infection. The success of vertical transmission of B. microti in this group was 63%. No evidence of pregnancy was found in females mated during the acute phase of infection or on the 4th day of pregnancy. In the group infected on the 12th day of pregnancy, numerous complications including loss of pregnancy and stillbirths were recorded. During the acute phase of infection, parasitaemia was lower in pregnant females in comparison to infected, non-pregnant control females. Conclusions: Acute B. microti infection prevents the initiation of pregnancy and embryonic development if it occurs during the first trimester, and causes severe complications in foetal BALB/c mice in the second and third trimesters of pregnancy. Chronic B. microti infection has no detrimental impact on the initiation and development of pregnancy, but results in congenital infection of the offspring. Further study is required to determine the extent to which maternal anti-babesial immune responses contribute to compromise pregnancy in the murine model of congenital Babesia infection. Graphical

Toxoplasma gondii is a significant pathogen affecting humans and animals. We conducted seromonitoring for T. gondii in four sylvatic rodent species in Poland. We report an overall seroprevalence of 5.5% (3.6% for Myodes glareolus and 20% for other vole species). Seroprevalence in bank voles varied significantly between host age and sex.