Post-Mortem Evaluation of Pathological Lesions in European Bison (Bison Bonasus) in the Białowieża Primeval Forest Between 2008 and 2013

Abstract

The study presents the analysis of the findings of 234 post-mortem examinations on free-ranging and captive European bison selectively culled or having fallen between 2008 and 2013 in Białowieża Primeval Forest. Pneumonia, emphysema, nephritis, bodily traumas, and intestinal lesions were observed in 106 (45.3%), 77 (32.9%), 82 (35.0%), 68 (29.1%), and 56 (23.9%) animals respectively and were the most common pathological changes. Almost half of all males (66 out of 140; 47.1%) tested showed some pathological changes of prepuce and penis, described as posthitis or balanoposthitis. Infection with liver fluke (Fasciola hepatica) and lungworm (Dictyocaulus viviparus) was observed macroscopically in 114 (48.7%) and 80 (32.9%) bison respectively. F. hepatica prevalence was associated with the emergence of other liver changes such as hepatitis and cirrhosis (P < 0.001). Similarly, the prevalence of D. viviparus coincided with pneumonia (P = 0.001), changes in the upper respiratory tract (P = 0.04), and emphysema (P < 0.001). Hepatitis, infection with F. hepatica, and pathological lesions in the male and female reproductive tracts were associated with the animals' age. Mechanical injuries, caused by other bison or less commonly by traffic accidents, were the most common cause of death of bison below six months of age. Most pathological changes were significantly more frequent in the selectively culled animals in comparison with the ones having fallen, which confirms the desirability of elimination as a tool to improve the health and welfare of the bison population and limit the number of reservoirs of invasive and possibly infectious diseases.

Infectious Disease Monitoring of European Bison (Bison bonasus)

“…Dr. Wróblewski observed pleuropneumonia caused by Pasteurella multocida and connected to the Strongylidae invasions of lungs [15]. The problem of purulent pneumonia is still observed in European bison at Białowieża [6]; however the agent, Pasteurella multocida subsp. multocida serogroup A was identified just recently [16].…”

“…The first signs of another important disease in the male European bison, referred to as necrotic posthitis or balanoposthitis (called also pizzle rot), the causes of which still remain unsolved, were observed in Białowieża in 1980 remain unsolved, were observed in Białowieża in 1980 (Figure 3) [22]. Trueperella pyogenes and some other purulent bacteria have been isolated from the diphtheroid-necrotic changes observed on the prepuce and penis, which may lead to self-mutation of the penis in severe cases causing primarily great pain and immunosuppression, excluding the affected males from breeding [6,[22][23][24]. Infection with BoHV-1 causing similar symptoms in cattle was excluded from the investigation, since hardly any European bison affected had detectable antibodies to the virus and no isolation from the tissues was possible [1,22,25].…”

“…The epidemic of balanoposthitis in Białowieża included annually up to 15.2% males in 1993, with the average of 6.1% between 1980 and 2015. Selective culling was found the most effective method to decrease the cases, especially in the recent years [1,6]. The symptoms are observed in all age groups of males, including calves and 2-3-year-old European bison males, yet not reproductively active [1,6,23]; therefore venereal route of transmission may rather be rejected.…”

“…Selective culling was found the most effective method to decrease the cases, especially in the recent years [1,6]. The symptoms are observed in all age groups of males, including calves and 2-3-year-old European bison males, yet not reproductively active [1,6,23]; therefore venereal route of transmission may rather be rejected. Since most cases occurred at Białowieża Forest, involvement of some environmental or vectors such as ticks was speculated, however, never verified.…”

Ante-mortem and post-mortem tuberculosis diagnostics in three European Bison from the enclosure in Bukowiec in the Bieszczady National Park in Poland

“…The animals were pharmacologically immobilised to restrain them. Their weight was estimated primarily on the basis of data on the biology of European bison and data obtained by the weighting of culled animals or fallen stock (8,12). As recommended by the literature, a dose of two combined active substances, etorphine hydrochloride and xylazine, was administered (9).…”