Endoparasite loads and the efficacy of conventional anthelmintics against gastrointestinal nematodes in captive European bison

Although little information exists on the efficacy of deworming in wild ruminants, gastrointestinal nematodes have been found to demonstrate increasing drug resistance. The spread of drug-resistant strains may be increased by transmission among livestock and susceptible wildlife species, thus posing a potential threat to endangered species, such as the European bison. The aim of the study was twofold: to identify the parasite loads in captive European bison with the use of coprological techniques, and to test the influence of other nearby ungulates on the richness of bison parasitofauna. Additionally, the efficacy of deworming procedures against gastrointestinal nematodes in bison was evaluated. The survey was based on a coprological investigation of 285 fecal samples from 156 European bison in 15 enclosures. The parasitofauna of the captive European bison was consistent with those of free-ranging populations. The highest prevalence was noted for Eimeria spp. oocysts (60.7%), strongyle eggs (50.9%), Fasciola hepatica eggs (13.1%), Dictyocaulus viviparus larvae (12.3%) and Trichuris sp. Eggs (9.47%). Moreover, the close proximity of other ungulate species resulted in a higher diversity of parasite species. In all cases, deworming with albendazole, fenbendazole and ivermectin proved to be ineffective against strongylids and Trichuris sp. The results of fecal egg count reduction test (FECRT) ranged from 37.2 to 99.6% (95% CI <90%) for albendazole; values >95% (95% CI = 41-100) were noted for fenbendazole, and FECRT ranged from 63.2 to 97.5 (95% CI = 0-99) for ivermectin. As the results of anthelmintic treatment are unsatisfactory, it seems justified to continue study in this area. Our study is the first large-scale attempt to evaluate the efficacy of anthelminthics in captive European bison. The potential sharing of parasite species between bison and other ungulates should also be further investigated from the perspective of minimizing the risk of the spread of drug-resistant parasite strains.

First report of a newly-described lungworm, Dictyocaulus cervi (Nematoda: Trichostrongyloidea), in moose (Alces alces) in central Europe

Lungworms from the genus Dictyocaulus are the causative agents of verminous pneumonia in domestic and wild ungulates. Recently, in 2017, a new species was isolated from red deer and described as Dictyocaulus cervi; however, little is known about its epidemiology and pathogenicity in other cervids. The aim of our study was to determine the extent of infection with Dictyocaulus nematodes in the moose population in Poland. Parasitological necropsies were performed in 18 moose and 249 faecal samples were analysed. A combination of multiplex PCR and analysis of the partial SSU, cox1 and cyt B regions revealed the presence of D. cervi infection in two of the necropsied moose. Histopathological examinations revealed changes, including multiple cross sections of larvae of nematodes in alveoli, massive pulmonary fibrosis, mononuclear cell infiltration and diffuse alveolar damage in the lungs of four animals. The lesions were more pronounced when adult Dictyocaulus nematodes were present in the bronchi and bronchioles. Some of the observed pathological changes could be attributed to co-infection by nematodes of the Protostrongylidae, whose larvae were found in all four animals with lung pathologies. In the faeces, Dictyocaulus sp. larvae only occurred together with Protostrongylidae larvae; in addition, higher numbers of Protostrongylidae larvae were excreted in the faeces of animals with dictyocaulosis. The present study is the first report of the presence of D. cervi in moose, and demonstrates the value of multiplex PCR in the identification of Dictyocaulus nematodes. Our findings indicate that co-infections with multiple species of lung nematodes in moose may be commonplace, and this should be considered as a factor aggravating the course of parasitosis.

Large lungworms (Nematoda: Dictyocaulidae) recovered from the European bison may represent a new nematode subspecies

Although the Dictyocaulus lungworm, the agent of dictyocaulosis, is one of parasitological threats to European bison, its systematic position remains unclear. The aim of the present study was to evaluate the morphological features of the lungworm and the pathological lesions it induces, and to analyse mitochondrial (mt) genetic markers for systematic and molecular epidemiological studies. The morphological findings indicate that Dictyocaulus lungworms of European bison can be distinguished from those of cattle on the basis of differences in buccal capsule wall length, total body length, and spicules length in males, all of which were significantly longer in those of European bison. Nucleotide diversity calculated from pairwise sequence alignments of partial cytochrome c oxidase subunit 1 (cox1), cytochrome B (cytB) and NADH dehydrogenase subunit 5 (nad5) of specimens from cattle and European bison varied from 1.7% for nad5, 2.1% for cytB, to 3.7% for cox1 gene. Thus, among the lungworms of European bison and cattle, nad5 and cytB were the most conserved proteins, whereas cox1 was the most diverse. The mt cytB marker gene may be a suitable candidate for distinguishing between the two genotypes, as nad5 demonstrated the greatest within-genus sequence variation. The lung tissue of infected European bison manifests signs of verminous pneumonia characterized by interstitial pneumonia, bronchitis and bronchiolitis. Therefore, it appears that European bison and cattle are infected with slightly diverged, morphologically-different, genotypes of D. viviparus, indicating they belong to two separate worm populations. We propose, therefore, that the lungworm of European bison should be classified as D. viviparus subsp. bisontis.

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European bison harbour a unique morphotype and genotype of Dictyocaulus viviparus.

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Mt cytB is an efficient genetic marker for studying large lungworms in bovids.

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European bison lungworm can be classified as D. viviparus subsp. bisontis.

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Pathologies induced by a newly described nematode subspecies mirrored those of lungworm in cattle.

Usefulness of PCR-RFLP of 18S rRNA gene for rapid post-mortem diagnostics of highly pathogenic Eimeria spp. (Apicomplexa: Eimeriidae) of European bison, Bison bonasus L. with histopathological correlation

Eimeria spp. infection was investigated in 10 free-roaming European bison aged three months to 26 years by anatomopathological, histopathological, coproscopic and PCR-RFLP examination. The coproscopic study identified Eimeria oocysts in the faeces of five bison. The most prevalent morphotypes were E. bovis, present in all positive samples, and E. zuernii, in all but one. Additionally, mixed infections consisting of E. bovis, E. zuernii, E. alabamensis, E. auburnensis, E. canadensis, E. cylindrica, E. ellipsoidalis and E. subspherica were diagnosed in two bison calves. Besides being the most prevalent form, E. bovis also demonstrated the highest OPG (2,750). The presence of oocysts in the faeces was associated with those of macrogamonts, microgamonts and oocysts in the epithelium of the large intestine. Intestinal coccidiosis associated with lymphoplasmacytic enteritis was observed in many bison, not only those with positive OPG. Four animals with negative coproscopy results demonstrated early-stage gametogony in the large intestine; one case presented no endogenous stages of coccidians in the histopathological sections of the intestine, nor oocysts in the faecal samples. A 530 bp product of E. bovis 18S rDNA (GenBank: MK951685) was obtained from both the colon wall and oocysts; this was subjected to PCR-RFLP analysis based on AluI and Hin1II (NlaIII) restriction enzymes. Both samples yielded a consistent seven-band pattern, four of which (270 bp, 40 bp, 180 bp and 84 bp) were expected, and the other three represented undigested fragments. The obtained digestion pattern is indicative of Eimeria spp. infection, and can serve as a first-step diagnostic approach in detection of infection. The result of computer-based virtual digestion of the PCR product suggests that double digestion with Mval (BstNI) and KpnI restriction enzymes may be used as a second-step tool to distinguish between E. bovis, E. zuernii and E. alabamensis, all of which are highly-pathogenic species.

The morphological and molecular identification of the tapeworm, Taenia lynciscapreoli, in intermediate and definitive hosts in Poland

The tapeworm Taenia lynciscapreoli is a new species of the genus Taenia described in 2016, and which remains poorly understood. The aim of the present study is to extend current knowledge regarding its, morphology and genome. Biological material was analysed from three species of wild animals: Eurasian lynx (Lynx lynx), roe deer (Capreolus capreolus) and moose (Alces alces). Twenty-four adult tapeworms and four larvae were obtained from Eurasian lynx and roe deer respectively; none were detected in the studied moose. On the basis of morphometric (hooks measurements) and molecular analysis (partial 780 bp cox 1 gene sequences), the analysed tapeworm was identified as Taenia lynciscapreoli species. The phylogenetic analysis of the obtained sequences identified two haplotypes. The obtained findings can be used to supplement the species description. To our knowledge this is the first morphological and molecular identification of T. lynciscapreoli in roe deer, intermediate host, in Poland.

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Study is molecular and morphological identification of T. lynciscapreoli in Poland.

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78 animals from three species were examined: roe deer (71), moose (6) and lynx (1).

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28 parasites specimens were analysed: larvae (4), adult (24).

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This is the first identification of T. lynciscapreoli in roe deer in Poland.

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New description of the tapeworm should include that the number of hooks is 30–38.

Occurrence of tapeworms Moniezia benedeni (Moniez, 1879) in European bison Bison bonasus L. in Białowieża Primeval Forest

Tapeworms Moniezia benedeni are cosmopolitan parasites of wild and domestic ruminants. The aim of this study was to examine the prevalence of those tapeworms in European bison in Białowieża Primeval Forest. Parasitological necropsy of small intestine of 26 bison, aged from 3 months to 26 years was performed in years 2007–2011. Tapeworms M. benedeni were isolated from 11 examined animals and the prevalence of infection was estimated on 42.3%. Intensity of infection was ranging from 2 to 25 tapeworms and the mean intensity was estimated on 5.8 specimens. Prevalence in the group of calves reached 50% and in adult bison – 33.3%. Intensity of infection in calves was estimated on 2 to 5 tapeworms while in adult animals it was ranging from 1 to 2 parasites. High prevalence of tapeworms M. benedeni in European bison might result from poor condition or weak immunity of eliminated animals.

Pathological lesions in the lungs of red deer Cervus elaphus (L.) induced by a newly-described Dictyocaulus cervi (Nematoda: Trichostrongyloidea)

The large lungworms of the genus Dictyocaulus are causative agents of parasitic bronchitis in various ungulate hosts, including red deer. Recently, the red deer-derived lungworm D. cervi was described and separated from D. eckerti. Little is known of the transmission patterns, epidemiology, geographical distribution and pathogenicity of D. cervi. Histological examinations were performed on 22 formalin-fixed lung tissue samples of hunted red deer. Exclusively, D. cervi adults were derived from 15 red deer and confirmed molecularly (GenBank accession: MH183394). Dictyocaulus cervi infection was associated with various degrees of lung pathology, including interstitial pneumonia, bronchitis and bronchiolitis with an influx of eosinophils, lymphocytes, plasma cells and macrophages; massive hyperplasia of lymphoid follicles within bronchiolar tissue, and hyperplasia of the bronchial and bronchiolar epithelium. Furthermore, emphysema, atelectasis and lung tissue congestion were noted. Interestingly, interstitial and subpleural fibrosis was seen in adult Dictyocaulus-negative samples, suggesting either a prepatent phase of Dictyocaulus infection or infection/coinfection with protostrongylid nematodes.

Increased Parasitic Load in Captive-Released European Bison (Bison bonasus) has Important Implications for Reintroduction Programs

Captive-bred animals, widely used in reintroduction programmes, are often immunologically naïve and more susceptible to pathogens. We analysed infection of invasive blood-sucking nematode Ashworthius sidemi in captive-bred European bison (Bison bonasus) released to the wild in the Białowieża Forest (Poland). Mean A. sidemi infection intensity of released bison (29,137 nematodes) was over threefold higher than in wild bison (8756). It indicates a rapid acquisition and increase in the infection intensity in previously dewormed bison released from captivity. Thus, reintroduction programmes should consider the impact of pathogens and involve controlled exposure of captive animals to specific parasites prior to release.

Expansion of Ashworthius sidemi in red deer and roe deer from the Lower Silesian Wilderness and its impact on infection with other gastrointestinal nematodes

Nematodes Ashworthius sidemi are typical parasites of Asiatic cervids, mostly sika deer (Cervus nippon). Migrating red deer have probably introduced this parasite to the area of Poland from neighbouring countries. The aim of the study was to determine prevalence and intensity of infection of red deer and roe deer from the Lower Silesian Wilderness with A. sidemi after one year from previous studies and to examine the influence of these parasites on other species of gastrointestinal nematodes. 31 abomasa of red deer and 3 abomasa of roe deer from Forest Dictrict of Ruszów have been examined on the presence of parasites. In comparison with previous studies, red deer showed significant, over triple increase of prevalence of A. sidemi and over fivefold increase of mean intensity of infection. Maximum intensity of infection has increased over 24 times. These results indicate on dynamic spread of this new aswortiosis foci. Apart from previously registered parasite species, four new nematodes have been found in examined red deer and roe deer during this year studies. Red deer have been infected with Spiculopteragia assymmetrica, typical for fallow deer and Haemonchus placei - typical for bovine, whereas roe deer have been infected with Trichostrongylus axei and Trichostrongylus capricola, parasites of sheep, goats and bovine. Prevalence of red deer infection with nematodes S. boehmi and Ostertagia leptospicularis was lower than two years ago while prevalence of infection with S. mathevossiani and O. kolchida was higher. Intensity of infection with these nematodes has increased.

The first report of Aelurostrongylus falciformis (Schlegel, 1933) (Nematoda, Metastrongyloidea) in badger (Meles meles) in Poland

Aelurostrongylus falciformis belongs to the superfamily of Metastrongyloidea. This nematode occurs in European badgers and locates in lungs, in respiratory tract. Numerous species of land snails are intermediate hosts of the parasite. In 2015, parasitological necropsy of 9 badgers, shot in the Forest District Głęboki Bród in Augustowska Primeval Forest, was performed. Two examined animals were infected with nematodes A. falciformis. In the lungs of each badger two specimens of nematodes were detected (male and female). In the following article, description, morphometrical data and figures are presented. This is the first report of A. falciformis infection in badgers in Poland.

Interrelationships of Dictyocaulus spp. in Wild Ruminants with Morphological Description of Dictyocaulus cervi n. sp. (Nematoda: Trichostrongyloidea) from Red Deer, Cervus elaphus

Lungworms from the genus Dictyocaulus cause parasitic bronchitis (dictyocaulosis) characterized by coughing and severe lung pathology in both domestic and wild ruminants. In this study we investigated the interrelationships of Dictyocaulus spp. from European bison (Bison bonasus L.), roe deer (Capreolus capreolus), and red deer (Cervus elaphus) by nucleotide sequence analysis spanning the 18S RNA gene (small subunit [SSU]) and internal transcribed spacer 2 (ITS2) regions of the ribosomal gene array as well as the mitochondrial cytochrome c oxidase subunit 1 (cox1). Molecular analyses of sequence data obtained partly with novel primers from between 10 and 50 specimens from each host were carried out. Bayesian inference analysis revealed that each host species was infected with different genotypes. Analysis of cox1 sequence data showed a diverse genetic background and high evolutionary potential of Dictyocaulus taxa. Data from lungworms of European bison revealed a distinct genotype of Dictyocaulus viviparus, whereas Dictyocaulus capreolus was only found in roe deer. In contrast, red deer were infected with a taxon with unique SSU, ITS2, and cox1 sequences. These results indicate the occurrence of a novel genotype from red deer, which differs significantly from the National Center for Biotechnology Information reference sequence of Dictyocaulus eckerti. The molecular evidence was consistent with a morphological study with description and imaging of Dictyocaulus cervi n. sp. recovered from red deer. Dictyocaulus cervi n. sp. can be distinguished from D. eckerti on the basis of the absence of cervical papillae, the occurrence of a single ring of 4 symmetrical submedian cephalic papillae, length of the tail in females, morphometry of the female reproductive system, and measurements of gubernacula in males. In conclusion, our findings further strengthen the idea that the genetic complexity and diversity among Dictyocaulus lungworms infecting wildlife ruminants is larger than previously believed and warrants further investigation.

Lymphocyte responses of rats vaccinated with cDNA encoding a phosphoglycerate kinase of Fasciola hepatica (FhPGK) and F. hepatica infection

Lymphocyte responses in the blood, peritoneal fluid and both mesenteric and hepatic lymph nodes of cDNA-FhPGK/pCMV vaccinated and/or Fasciola hepatica infected rats of both sexes were investigated to provide an insight into the immune responses that develop in different body compartments. The immune response that developed in cDNA-FhPGK/pCMV vaccinated females contributed to partial protection against F. hepatica infection (54% reduction in fluke recovery), while more liver flukes were found in the livers and bile ducts of cDNA-FhPGK/pCMV vaccinated male rats than in unvaccinated animals (increase of 13%). Rat sex not only affected the ultimate effectiveness of vaccination but also lymphocyte responses following vaccination and/or infection. Different CD4+ and CD8+ T cell profiles were noted in peritoneal fluid and lymph nodes, but not in blood, during acute and chronic fasciolosis. Moreover, independent lymphocyte responses developed in distinct body compartments. Immune responses of rats were polarized towards Th2/Treg with lymphocytes isolated from male rats showing higher IL-4 and IL-10 production than females. Lymphocyte proliferative capacities in response to mitogen (PHA) or vaccine antigen (FhPGK) were impaired in both sexes with a considerably higher reduction observed for males and restored lymphocyte proliferative capacities reported for females vaccinated with cDNA-FhPGK/pCMV during chronic fasciolosis.

A massive invasion of Parafasciolopsis fasciolaemorpha in elk (Alces alces) in Lublin Province, Poland

Liver fluke Parafasciolopsis fasciolaemorpha is a parasite typical of elk (Alces alces). The present study describes the identification of a massive invasion of the liver fluke P. fasciolaemorpha in an elk in the Sobibór Landscape Park, Eastern Poland. In February 2016, samples of liver and faeces were collected from the elk during postmorte examination. A section of liver tissue and three grams of faeces were examined for the presence of flukes or fluke eggs by decantation. In total, 11,150 juvenile and mature flukes of P. fasciolaemorpha were found in the examined liver. Multiple cavities with distinct walls, filled with dark liquid, trematodes, fluke eggs and cellular detritus were seen in the cross section of the parenchyma. Additionally, some of the bile ducts were plugged with calcerous deposits. The three grams of examined faeces were found to contain 322 grey and golden-coloured eggs of P. fasciolaemorpha. The presence of such a massive infection of P. fasciolaemorpha in the examined elk has a significant impact on the health of the individual. We can assume P. fasciolaemorpha has a significant influence on the health and abundance of the entire elk population in Poland.

KEY WORDS

Parafasciolopsis fasciolaemorpha, elk, Sobibór Landscape Park, Poland.

Coprology of a single Northern white-breasted hedgehog (Erinaceus roumanicus): first report of Isospora rastegaievae in Poland

Coprological analysis of a sample from one free-living hedgehog was done with the use of a direct flotation method with additional incubation of fecal material. The study revealed three types of eggs and oocysts in the feces. The most commonly diagnosed were oocysts of Isospora rastegaievae (543/3g), while oocysts of Monocystis sp. (267/3g) and eggs of Aonchotheca/Eucoleus spp. (52/3g) were seen less often. This is the first report of coccidia I. rastegaievae (Apicomplexa: Eimeriida) and acephaline gregarine Monocystis sp. (Apicomplexa: Eugregarinida) infection in a hedgehog in Poland.

Immune responses in rats and sheep induced by a DNA vaccine containing the phosphoglycerate kinase gene of Fasciola hepatica and liver fluke infection

Immune responses of rats and sheep following vaccination with cDNA encoding phosphoglycerate kinase of Fasciola hepatica (cDNA-FhPGK/pCMV) and F. hepatica infection were investigated in the present study. cDNA-FhPGK/pCMV vaccinated female Sprague-Dawley rats were better protected by vaccination than their male counterparts - 48% reduction in fluke burden for females and no protection for males when compared with appropriate infection control groups. Moreover, male rats developed marked leukocytosis during the study with higher neutrophil, eosinophil and monocyte responses than females. Additionally, dynamics of eosinophil and monocyte responses varied between sexes. Increased titres of anti-FhPGK IgG1 and IgG2a correlated with the protective effect of vaccination that was observed among female rats. In the case of male sheep, no differences in worm burdens and in the course of the immune response were observed following vaccination. Titres of specific antibodies detected were low, and cellular responses were not significant. Apparently, sheep immune responses induced by cDNA-FhPGK/pCMV vaccination are not effective at controlling F. hepatica infection. Poor immunogenicity of DNA vaccines in large animals is still a major obstacle of this technology that has to be overcome.

The infection of reintroduced ruminants - Bison bonasus and Alces alces - with Anaplasma phagocytophilum in northern Poland

The north-eastern part of Poland is considered an area of high risk for infection with tick-borne diseases, including with human granulocytic ehrlichiosis (HGE) agents. The etiological agent of HGE is Anaplasma phagocytophilum. As the animal reservoir for A. phagocytophilum in the environment serve the species from Cervidae and Bovidae families. European bison (Bison bonasus) and elk (Alces alces) are the big ruminant species, reintroduced to the forests of Middle Europe after many decades of absence. In the foci of zoonotic diseases they are able to play a role as natural reservoir to pathogens, however, their status as protected animals means their study has been rare and fragmentary. The studies of B. bonasus were conducted in Białowieża Primeval Forest and A. alces in Biebrza National Park. PCR amplifications were performed using primers amplifing the end of the groES gene, the intergenic spacer and approximately two-thirds of the groEL gene in the first round, and primers that span a 395-bp region of the groEL gene were used in the second round. The positive results were obtained in B. bonasus and A. alces, the prevalence of infection was 66.7 and 20.0%, respectively. Randomly selected samples were sequenced, sequences were compared with GenBank entries using Blast N2.2.13 and determined as A. phagocytophilum. The results presented herein are the first record of the presence of Anaplasma phagocytophilum in A. alces, and at the same time confirm the previous observations regarding the infection of B. bonasus with A. phagocytophilum.

Extension of occurrence area of the American fluke Fascioloides magna in south-western Poland

Liver fluke Fascioloides magna is a typical parasite of American cervids. The reason for F. magna to appear in Poland territory was bringing the American wapiti deer to those forests around 1850. Along with these deer the aforementioned fluke was also introduced. The aim of this study was to present the case of finding of this species in cervids in Bory Zielonogórskie. Samples of deer feces were collected in February 2015 in Forest District Krzystkowice. A total of 16 samples of feces were examined, 7 of which came from the red deer, 4 from roe deer and 2 samples from fallow deer. Three grams of feces from each sample were examined for the presence of trematode eggs using the decantation method. Eggs of F. magna were detected in 2 of 7 examined samples from red deer, in the first sample it were found 3 eggs, and in the second one 46 eggs. Moreover, flukes eggs were found in 3 out of 4 roe deer faecal samples, in numbers of 1, 3 and 58 eggs respectively in each sample. Also, in faecal samples from two fallow deer were found in one of them 17 eggs F. magna. The results of this study extend the range of occurrence of the trematodes F. magna on the neighboring Lower Silesia Forest complex of Bory Zielonogórskie which are distant about 50 km. Fallow deer and roe deer were considered to be new in Poland definitive hosts of F. magna. .

Coccidia (Apicomplexa: Eimeriidae) of the lowland European bison Bison bonasus bonasus (L.)

Coprological studies conducted between 2007 and 2011 in free-roaming and captive European bison Bison bonasus (Linnaeus, 1758) from Poland revealed 11 species of Eimeria infecting the host, i.e., Eimeria alabamensis, Eimeria auburnensis, Eimeria bovis, Eimeria brasiliensis, Eimeria bukidnonensis, Eimeria canadensis, Eimeria cylindrica, Eimeria ellipsoidalis, Eimeria pellita, Eimeria subspherica, and Eimeria zuernii. The typical host for all isolated species is cattle. The most prevalent species was E. bovis (29.7%), while E. brasiliensis was the rarest (0.5%). Five of the species (E. bovis, E. bukidnonensis, E. canadensis, E. ellipsoidalis, E. zuernii) have been observed previously in bison by other authors, 3 species were noticed by us in bison previously (E. alabamensis, E. cylindrica, E. pellita), while for 3 species (E. auburnensis, E. brasiliensis, and E. subspherica) these are new host and locality records. Oocysts of two species (E. brasiliensis, E. bukidnonensis) were noted only in the feces of bison kept in captivity. Moreover, the prevalence of positive samples was higher in the group of captive animals (55.4%) in comparison with the free-roaming herds (29.5%); although, oocysts per gram (OPG), counted with the conventional McMaster technique, was comparable in both groups, reaching maximally 6550 and 6400 in free-roaming and captive individuals, respectively. Overall, 142 fecal samples from 424 samples examined were positive for Eimeria (prevalence=33.5%). Age-related analysis revealed a higher percentage of Eimeria spp. positive samples and higher OPG values in bison under 1 year old as compared to older individuals (93.3% and 50-4050; 37.3% and 50-550, respectively). Additionally, greater eimerian species diversity was present among calves in comparison with older bison. In most cases single-species infections were observed (59.8%) with a predominance of E. bovis (85.9%). Multiple-species infections consisted of 2-7 species, usually including E. bovis. The observation was made that E. bovis infection appears conducive to the host acquiring more eimerian species. No symptoms of clinical coccidiosis occurred during the study.

The prevalence and distribution of Dirofilaria repens in dogs in the Mazovian Province of central-eastern Poland

The aim of this study was to determine the prevalence and distribution of canine dirofilariosis from different districts of the Mazovian Province in central-eastern Poland. 462 dogs aged from 1.5-14 years were examined for dirofilariosis. Blood samples were examined for the presence of microfilariae using the Knott method, as well as the method of Kingston and Morton, after centrifugation in haematocrit microtubes in order to determine the intensity of infection as the number of microfilariae in 60 microliters of blood. The species of microfilariae found were determined after staining on the basis of the morphological characters. Samples were also examined using Canine Heartworm Antigen Test Kit SNAP HTWM (IDEXX, USA) that allows the detection of circulating antigens of females of Dirofilaria immitis. The positive samples were examined using multiplex PCR assay for species confirmation. Microfilariae belonging to the species D. repens were found in the blood samples of dogs originating from the city of Warsaw and from 18 districts of Mazovian Province. The mean prevalence of that species observed in the province was 25.8%. The range of intensity counted with the number of microfilariae found in 60 microliters of blood amounted to between 1-150; median intensity 9 microfilariae. The highest prevalence, reaching 52.9% and the highest median intensity of infection reaching 28 microfilariae, was found in Radom district. The lowest prevalence, amounting to 4.2%, was registered in Grójec district; however, the lowest median intensity reaching 6 microfilariae was noted in Żyrardów district. The infected dogs had not been outside of Poland, which means that this is an autochthonous infection. Microfilariae and antigens of D. immitis were not found in any examined blood samples. Results of the presented study show that autochthonous dirofilariosis caused by nematodes D. repens commonly occurs in the area of the Mazovian Province.

Coccidia (Apicomplexa: Eimeriidae) of elk (Alces alces) in Poland

Over a 4-year period, we analyzed 128 fecal samples from free-living elk (Alces alces L., 1758) to determine the prevalence of Eimeria infections and identify the species present. Two eimerian species were isolated including Eimeria alces and a morphotype resembling Eimeria catubrina. Overall, two samples from 128 samples collected were positive for Eimeria (prevalence = 1.6 %), and the oocyst per gram, estimated with the use of the conventional McMaster quantitative technique, ranged from 50 to 100. Also, E. alces has been found in Lithuania and Belarus and is the only known species of eimerian to infect elk. E. catubrina is a parasite typically infecting roe deer (Capreolus capreolus L., 1758). This is the first report of Eimeria spp. in elk in Poland. Results of our investigation indicate that elk may become infected with an eimerian species that is typical for roe deer, but this requires further investigation.

Nematodes of the large intestine of the European bison of the Białowieza National Park

The present study was conducted on 31 males and females of the European bison, eliminated during the winter seasons 2007-2011 in the Białowieza Primeval Forest, Poland. The caeca of 14 free-ranging bison, aged from 3 months up to 16 years, the most favorable infection site for the large intestine nematodes, were investigated during the winter of 2007/2008. The parasitological autopsies of the large intestines of 9 free-ranging bison aged from 5 months up to 10 years as well as 9 bison kept in the close reserves aged from one up to 20 years were done during the winter seasons of 2008-2011 to determine localization of nematodes in large intestine and the total intensity of parasite infection. Five species of nematodes (i.e., Trichuris ovis, Oesophagostomum venulosum, O. radiatum, Ashworthius sidemi, Nematodirus helvetianus) were found in dissected caecum of bison culled during the winter of 2007/2008. During the seasons of 2008-2010, 6 species of nematodes were found in the large intestine of bison (i.e., T. ovis, O. venulosum, O. radiatum, A. sidemi, N. roscidus and Bunostomum trigonocephalum). We did not find any nematodes in the lumen of the large intestine of captive bison culled during the seasons of 2010/2011. The results of the present study indicate that the intensity of infection by the large intestine nematodes of the European bison in the Białowieza Primeval Forest has stayed at the comparable level throughout the last 20 years; however the number of nematode species has increased. The observed level of parasitic infection is typical of subclinical parasitoses.

The annual cycle of shedding Eimeria oocysts by European bison (Bison bonasus) in the Bialowieza Primeval Forest, Poland

Between April 2008 and March 2009, we analyzed the pattern of coccidian oocysts present in the feces of the European bison (Bison bonasus L., 1758) and found 4 species (Eimeria bovis , E. canadensis, E. ellipsoidalis, E. zuernii) previously reported from this host and 3 species (Eimeria alabamensis, E. cylindrica, E. pellita) that are new host and locality records. All the species occurred in bison females, and only 4 occurred in males; E. bovis was the most prevalent in both sexes. The overall prevalence of Eimeria spp. invasion reached 34.7% in cows and 13.9% in bulls. The highest prevalence was noted in early spring, with a peak in April, and the lowest in late autumn and winter. The oocyst count per gram of feces (OPG) varied from 50 to 1,350; no symptoms of clinical coccidiosis were observed. We found a significant influence of winter aggregations of bison on shedding of coccidian oocysts. The prevalence and OPG values were higher in bison congregating in large numbers around winter-feeding sites in comparison to other sites. We suggest that the coming together of cows during the growing season impacts the gender-related differences in prevalence and the number of coccidian species involved. This observation probably results from an increased production of oocysts by sub-clinically infected individuals in high-density bison populations.

[The first foci of dirofilariosis of dogs evoked by Dirofilaria repens Railliet et Henry, 1911 in central Poland]

Dirofilariosis is caused by nematodes Dirofilaria repens Railliet et Henry, 1911. This parasitosis is widely distributed in south Europe among dogs, cats and wild carnivorous. It occurs also in Asia and Africa. Adult nematodes D. repens locate in nodules, in subcutaneous or intramuscular connective tissue of dogs. The mosquitoes from genera Anopheles, Aedes and Culex are the intermediate hosts and vectors of mentioned parasites. The finding of 6 adult nematodes belonging to the species D. repens in scrotum under tunica vaginalis, during the castration of the dog, which has never been abroad, tended us to undertake presented studies. In August and September of 2009, 64 genuine dogs age from 1.5 to 12 years originated from 3 kennels in central Poland were examined. Dogs did not show any pathological symptoms of infection. Blood samples were examined for the presence of infection and a number of microfilariae. Species of microfilariae was determined after staining on the basis of morphological characters. In examined blood samples from dogs microfilariae belonging to the species Dirofilaria repens were found. Mean prevalence of infection in all examined kennels was 37.5% and mean intensity 32 microfilariae in 30 microl of blood. Microfilariae of D. immitis were not found in any examined blood samples. The results of presented studies show that native dirofilariosis of dogs caused by D. repens is common in central Poland. The result of our investigations lets us suppose, that the range of occurrence of D. repens will spread significantly towards north Europe.

[Sarcocystis cruzi (Protozoa: Apicomplexa: Sarcocystiidae) infection in european bison (Bison bonasus) from Białowieza Forest, Poland]

Samples of oesophagus, diaphragm and heart muscles were taken from one European bison from Białowieza Forest during seasonal European bison elimination in 2008. Five gram of each muscle was examined by staining small samples in 0.2% aqueous solution of methylene blue. After that they were placed between compressor glasses and examined under a dissecting microscope in order to detect Sarcocystis sp. infection. All sarcocysts observed were counted. The 5-g sample of the heart muscle yielded a total of 756 sarcocysts while that of the diaphragm contained 107 of them and that of the oesophagus--89. All of the sarcocysts were isolated from 1 g of each muscle by using preparation needles (probes). After that the sarcocysts were taken to 0.5% physiological solution and examined under light microscope. The special attention was paid to detection of their cyst wall, which was thin (1 microm up to 1.2 microm) and smooth in all cases. Sometimes villar protrusions were seen on the surface of the cysts. Differences between the size of sarcocysts isolated from different muscle samples were observed. The longest and the slenderest sarcocysts were found in the diaphragm. Slightly smaller in the oesophagus and the smallest ones in the heart muscle tissue. The average size of sarcocysts isolated from diaphragm was 957.6 microm x 112.7 microm. Sarcocysts found in the oesophagus measured 484.1 microm x 194.6 microm and those isolated from the heart muscle attained 305.4 microm x 103.9 microm. All of the sarcocysts isolated from heart, oesophagus and diaphragm muscles were identified Sarcocystis cruzi.

[Occurrence of coccidia from genus Eimeria in European bison in Białowieza Forest, Poland]

Protozoa from the genus Eimeria belong to the least recognized parasites of the European bison. There are only a few data concerning the infection of the bison by these protozoa in Białowieza Forest. In the winter of 2007/2008 weighting 3 g fecal samples from the rectum of 16 shot bison were examined by flotation method. In 13 of them were found coccidian oocysts from genus Eimeria, which were determined to the species by morphometric study under the microscope. In all 13 positive samples, it is 81.2%, oocysts of Eimeria bovis were found. Intensiveness of this infection oscillated from 1 to 181 and the mean one was 38 oocysts. E. zuernii was found in 9 samples in the mean intensity 19 (1-154) oocysts. E. ellipsoidalis occurred in 3 bison with a very low intensity 1 to 3 oocysts. The most rarely occurred E. canadiensis, only in 2 examined bison in the number of 2 and 3 oocysts. All found coccidian species are the typical parasites of cattle. Białowieza Forest is a new place of occurrence of these parasites. European bison is a new host for E. zuernii.