Immunohistochemical study on the expression of biologically active substances in the endocrine pancreas of the European bison.

Previous morphological studies of mammalian pancreatic islets have been performed mainly in domestic and laboratory animals. Therefore, the present immunohistochemical investigation was conducted in a wild species, the European bison, using antibodies against glucagon-like peptide-1 (GLP1), glucagon, insulin and somatostatin. Morphological analyses revealed that the mean area of the endocrine pancreas constituted 2.1±0.1% of the whole area of the pancreas, while the mean area of a single pancreatic islet was 13301.5±686.5 µm2. Glucagon-immunoreac- tive cells accounted for 22.4±1.1% and occupied 19.4±0.4% of the average islet area. As many as 14.3±1.4% of pancreatic islet cells were shown to express GLP1, which constituted 12.6±0.8% of the mean area of the islet. Insulin expression was confirmed in 67.6±0.7% of pancreatic islet cells, which represented 62.3±4.9% of the mean total area of the pancreatic islet. As many as 8.5±1.3% of cells stained for somatostatin. The somatostatin-immunoreactive cell area was 4.9±0.3% of the mean pancreatic islet area. In summary, we have determined in detail for the first time the morphometry and islet composition of the European bison pancreas. The distri- bution patterns of immunoreactivities to the substances studied in the European bison show many similarities to those described in other ruminant species.

Serological Study of Exposure to Selected Arthropod-Borne Pathogens in European Bison (Bison bonasus) in Poland.

Bison bonasus is an indigenous species of Central and Eastern Europe with the largest wild population inhabiting Bialowieza Primeval Forest; however, free-living and captive European bison are reared in many countries around the world. Despite that the European bison was rescued from the extinction after the First World War, it remains as endangered species. Changing environment as well as human activity may have contributed to the observed increase of the risk of the emergence and re-emergence of pathogens. The aim of the survey was to establish the distribution of four pathogens transmitted by arthropods including three arboviruses [Bluetongue disease virus (BTV), Epizootic haemorrhagic disease virus (EHDV) and Schmallenberg virus (SBV)] and a bacteria (Francisella tularensis) in the main populations of European bison in Poland. A total of 251 European bison originating from eight main populations were included in the study and sampled between February 2011 and December 2014. Serum samples originated from chemically immobilized, eliminated or dead by natural causes animals. Additionally, 65 cervids from Bialowieza Forest were tested to compare the seroprevalences of other ruminants inhabiting the same environment. The antibodies to SBV and BTV were found in 76.1% and 24.7% of European bison, respectively. In autumn 2012, simultaneous emergence of SBV and BTV in European bison was observed; however, while SBV has spread in all populations scattered around the country, BTV infections were observed only in the north-eastern part of Poland, where BTV cases have been previously reported in domestic ruminants. European bison age was found to be the only significant risk factor for SBV and BTV seroprevalences; however, this association was connected to the animal size, rather than to the length of exposure. None of the animals tested positive for antibodies against EHDV or F. tularensis. SBV exposure rate of cervids was much lower (35.4%) than in European bison, while BTV seroprevalence was comparable in both groups.

A serological and molecular study on the occurrence of mycoplasmas in European bison (Bison bonasus) from two areas of Eastern Poland.

European bison (Bison bonasus) from two different areas of Eastern Poland showing gross pathology possibly associated with mycoplasma infections were tested for ruminant Mycoplasma species using serological and molecular methods. Fifty-five samples, blood or tissue were collected from 28 animals during 2013-2014. Six sera were positive for Mycoplasma bovis. The ELISA and complement fixation test for Mycoplasma mycoides subsp. mycoides gave a few weak reactions, but were negative by immunoblotting and molecular methods.

Hepatitis E virus antibody prevalence in wildlife in Poland.

Hepatitis E is an important public health problem mostly in developing but occasionally also in industrialized countries. Domestic and wildlife animals are considered reservoirs of the hepatitis E virus (HEV). Since no information on the prevalence of autochthonous HEV infections in human and animal in Poland is available, the aim of the study was to investigate the HEV seroprevalence of different wildlife species as potential virus reservoirs in the country. No HEV antibodies were found in any of the sera collected from the red deer (Cervus elaphus), European bison (Bison bonasus), roe deer (Capreolus capreolus), elk (Alces alces), fallow deer (Dama dama), sika deer (Cervus nippon), Tatra chamois (Rupicapra rupicapra tatrica) or brown bear (Ursus arctos). HEV-specific antibodies were detected in 44.4% (95% CI 38.3-50.7) serum samples originated only from wild boars. The percentage of seropositive wild boars differed significantly between the provinces and was positively correlated with the wild boar density and rurality of the area. This study showed that HEV circulates among wild boar population in Poland, and this species should be considered as an important reservoir of the virus.

Detection of Borrelia burgdorferi sensu lato DNA in the blood of wild bison from Bialowieza primeval forest in eastern Poland.

The aim of the present study was to investigate the occurrence of Borrelia burgdorferi sensu lato DNA in a group of 120 wild bison (Bison bonasus) from the Bialowieza Primeval Forest in eastern Poland. The PCR technique revealed the presence of 16S RNA of Borrelia burgdorferi sensu lato in the blood of 16 out of 120 examined animals. DNA amplification by means of primers SC1 and SC2 gave a product with a size of 300-bp. The sequences of the PCR products obtained showed 100% homology with each other and 100% homology with B. burgdorferi s.1. 16S RNA gene DQ111061. Results of this study suggest that wild bison are important in maintaining agents of Lyme borreliosis, and that studies of reservoir competence of this species are indicated.

Serological studies to determine the occurrence of Johne's disease and mycoplasma infection in the Northern-East Polish population of European bison (Bison bonasus).

A serological study of twenty three European bison (Bison bonasus) derived from Northern-East Poland for the seroprevalence of Mycobacterium avium subsp. paratuberculosis, Mycoplasma bovis, Mycoplasma mycoides subsp. mycoides SC, Mycoplasma agalactiae and Mycoplasma capricolum subsp. capripneumoniae was conducted. Only specific antibodies to M. bovis were detected in two animals (8.7%) which were connected with the clinical signs and macroscopic anatomopathological lesions.