Ecology: Searching for sources of bovine tuberculosis transmission

Monitoring of Mycobacterium bovis in the faeces of badgers may help to identify potential reservoirs of the bacterium that cause bovine tuberculosis, according to a study in Scientific Reports this week. However, it is unclear whether the M. bovis found in these samples is capable of infecting cattle.

The European badger (Meles meles) is implicated as a potential reservoir of M. bovis and it is suggested that exposure to infected badger urine and faeces might be one route of transmission to cattle. Thus, Hayley King and colleagues propose that potential infection hotspots can be identified by quantifying the presence of M. bovis in badger faeces. They analysed samples collected from 12 badger social groups over the course of a year, and found evidence of M. bovis in samples from every group. More M. bovis seemed to be excreted from badgers in summer than any other season, which implies that badger faeces may represent a seasonally variable environmental reservoir. The authors did not assess the viability of the M. bovis and note that further research is required to determine whether M. bovis can survive in and be transmitted from this potential environmental reservoir.

The spread of bovine tuberculosis is a major economic burden on the cattle industry, especially in Great Britain where it has caused substantial economic losses. Understanding patterns in environmental contamination could help in the design of more effective strategies to combat this disease.