Tuberculosis in Southern Brazilian wild boars (Sus scrofa): First epidemiological findings

Abstract

Bovine tuberculosis (bTB) is a zoonosis caused mainly by Mycobacterium bovis that affects domestic and wild animals. In Brazil, there are no epidemiological studies on tuberculosis in wild animal populations and their possible role in the disease maintenance in cattle herds; thus, the aim of this study was to evaluate the occurrence of tuberculosis in wild boars in Rio Grande do Sul, southern Brazil. Tissue samples of animals hunted under government consent were submitted to histopathology and M. bovis polymerase chain reaction (PCR) as screening tests; the positive samples were subsequently submitted to bacterial isolation, the gold standard diagnosis. Eighty animals were evaluated, of which 27.9% and 31.3% showed histopathological changes and M. bovis genome presence, respectively. Moreover, 23.8% of the animals had at least one organ with isolates classified as Mycobacterium tuberculosis complex (MTC). Three hunting points were risk factors for positive results on screening tests. This study shows the occurrence of tuberculosis in a wild boars' population, and raise the possibility of these animals to play a role as disease reservoirs in southern Brazil. These results may help to improve the Brazilian tuberculosis control programme, as well as elucidate the circulation of mycobacteria in this country.

Mycobacterium tuberculosis var. tuberculosis infection in two captive black capuchins (Sapajus nigritus) in Southern Brazil

“…Once suspicious colonies were observed in mycobacteria media, DNA extraction was performed according to a previously described method [10] with adaptations [11], followed by subsequent quantification through spectrophotometry. Mycobacterium tuberculosis variants were differentiated by polymerase chain reaction (PCR) through the presence or absence of differential 16S RNA ribosomal gene differential regions, RD1, RD4, RD9, RD12, RD1 mic , and RD2 seal [12].…”

Development and Challenges in Animal Tuberculosis Vaccination

“…There is scientific evidence that wild boar plays a crucial role in the maintenance of MTC in the Iberian Mediterranean ecosystems [145,147,148]. Nevertheless, TB was reported in this species in many European countries [145], Asia [149], North Africa [150] and South America [151]. BCG and HIMB vaccines, by parenteral or oral route, have shown in this species a significant protection in different laboratory challenge trials (see Table 4).…”

Genomic and temporal analyses of Mycobacterium bovis in southern Brazil

“…We were able to identify processes associated with geographical localization, such as transmission occurring between contiguous herds, herds with the same owner and herds within the same region, but given the distribution of our fastBAPs clusters a higher level of long-distance transmission is probably helping to homogenize the M. bovis population across the state with little or no geographical clustering being observed. Additionally, whilst there are confirmed cases of bTB in wild boar in RS [102], to date no WGS has been done on these isolates to assess their similarity to local bovine isolates, so it would be premature to speculate on the role wild boar may play in maintaining bTB reservoirs in RS. [105].…”