Ten Years of Animal Tuberculosis Monitoring in Free-Living European Bison (Bison bonasus) in Poland

In the period 1996–2012, two outbreaks of animal tuberculosis were noted in the population of free-living European bison (Bison bonasus caucasicus) in the Bieszczady Mountains, Southern Poland. As the European bison is an endangered species and particularly susceptible to tuberculosis, not to mention a national icon, the decision was made to test all deceased bison for TB in Poland. The screened bison were obtained by elimination due to poor health or natural death. A total of 159 European bison have been examined over the last 10 years. The individuals came from four regions of Poland (Białowieża Forest, Bieszczady Mountains, Borecka Forest, Knyszyńska Forest), not only from the area where tuberculosis is still endemic. Mycobacterium bovis and Mycobacterium avium spp. hominisuis were identified in two different herds. The isolation of M. bovis from European bison was the first case described in Poland. So far, the only causative agent of tuberculosis identified in European bison in Poland, both in the wild and in captive herds, was Mycobacterium caprae. The isolated M. bovis spoligotype has not previously been registered in international spoligotype databases so far. The obtained results highlight the need to monitor TB in European bison in Poland.

The first visually-guided bronchoscopy in European bison (Bison bonasus) - An additional tool in the diagnosis of bovine tuberculosis?

The European bison (Bison bonasus, EB) is an endangered species, and as about 1/3 of its global population is found in Poland, it is particularly important that Polish herds should be monitored. One particular concern is tuberculosis, which is not a marginal problem in wildlife in Poland, and has been microbiologically confirmed in EB, wolves (Canis lupus) and wild boar (Sus scrofa). However, ante mortem diagnosis of tuberculosis in EB is troublesome. Therefore, the present paper evaluates the potential of bronchoscopy as a diagnostic tool. Seven EB were studied, four of which were found to be naturally infected with M. caprae; in two of these, endoscopy identified abnormalities in the respiratory tract ante mortem. Therefore, despite some limitations, endoscopy can be an additional tool for diagnosing tuberculosis in EB, especially in highly valuable animals, and to assess the stage of the disease.

Vertical transmission of anti-ASFV antibodies as one of potential causes of seropositive results among young wild boar population in Poland

The present study attempted to elucidate possible routes leading to the achievement of sero- positive results, among young (aged ≤1 year) wild boar population. In the years 2017-2018, the National Reference Laboratory (NRL) for African swine fever (ASF) in Poland examined nearly 27-thousand wild boar blood samples, collected during an active surveillance of ASF risk zones, for the presence of viral DNA and anti-ASFV antibodies. Out of all the examined samples, 420 were positive. However, in more than half of them (292 samples) antibodies against African swine fever virus (ASFV) were detected, while ASFV DNA was not detected in blood. Out of all 292 seropositive/PCR-negative samples, 126 belonged to young wild boars (aged ≤1 year). For this reason, the NRL in Poland has examined 10 selected seropositive wild boar carcasses to confirm or exclude post-mortem lesions for ASF as well as to investigate the presence of viral DNA in the internal organs. Neither pathological lesions for ASF nor the presence of genetic material of ASFV were found in the examined wild boars. To elucidate this outcomes, following hypotheses about possible reasons of the obtained results were drawn: the presence of convalescent animals, infection of low-virulent ASFV isolate and the vertical transmission of antibodies through the colostrum.