5 FINAL CONSIDERATIONS
By combining epidemiological history and WGS of M. bovis strains, we show that the increase in fatal cases observed in the safari park coincided with changes in populational density and nutritional status, and that many pathogen introductions occurred over time. These observations demonstrate that wildlife populations found to be chronically infected and frequently asymptomatic may suddenly suffer from acute, fatal disease following populational disturbances, such as the ones observed herein. The negligence of successive pathogen introductions likely potentiated the outbreak, contributing to disease spread in different animal species. The M. bovis strains circulating in the park were classified as Lb3 (CC Eu2), a common lineage found in Brazil, and share phylogenetic relationships with extant M. bovis strains circulating in farmed cattle. Thus, at some point in time, transmission occurred between cattle and the wildlife maintained in the safari park. The use of WGS to delineate the history of this outbreak highlights the importance of genomic surveillance to follow disease introduction into animal populations and transmission between individuals.
With this study we make a pledge for action. It is imperative that reporting of TB cases in wildlife, captive or free-ranging, becomes mandatory in Brazil as to understand the true size of the problem. This should follow increased investments in pathogen identification, as wildlife are affected by both M. bovis and M. tuberculosis(Murakami et al., 2012). Finally, a national plan for control of TB in wildlife should be designed to incorporate specific guidelines to contain and solve outbreaks and prevent possible zoonotic transmission to veterinarians and caretakers, considering species-specific conditions and difficulties in diagnosing the disease in wild animals, particularly when dealing with endangered species.