Bacteriology
The role of wildlife in the epidemiology of paratuberculosis
Dr Mike Sharp & Dr Karen Stevenson
Figure 1. A european red fox, vulpes vulpes. (Thanks to Sue Shwar for the image)
Table 1. Results of a survey investigating paratuberculosis in foxes and stoats.
| Species | Culture Posative | Lesions | Total |
| Fox Stoat |
23 17 |
12 1 |
27 37 |
Johne's disease is a common, chronic enteritis of all ruminants caused by the bacterium, Mycobacterium avium subspecies paratuberculosis. We have previously reported that this organism can infect not only domestic livestock but also several species of wild animals in the same environment, such as deer and rabbits. In conjunction with SAC and BioSS, we have been investigating the potential of other wildlife to be infected by M. a. paratuberculosis.
Foxes (Vulpes vulpes) and stoats (Mustela erminea) frequently eat rabbits. Therefore, these predators were collected as part of the farm vermin control programmes on several farms that have Johne's disease in both the ruminant livestock and rabbit populations.
M. a. paratuberculosis was cultured from tissues of all three predators from all farms. Many of these animals also had microscopic lesions with several features of Johne's disease of ruminants (Table 1).
This is the first reported isolation of M. a. paratuberculosis from fox and stoat. Until recently, natural M. a. paratuberculosis was considered only to infect domestic ruminants.
However, these results support the suggestion that M. a. paratuberculosis has a wider host range, and Johne's disease may have a more complex epidemiology than has previously been assumed. Rabbits and their major predators, foxes and stoats, and possibly other species, may harbour M. a. paratuberculosis, and act as a reservoir of infection, perpetuating the cycle of disease on the farm. Thorough understanding of all potential wildlife reservoirs is necessary for the development of informed control plans to combat Johne's disease.
Further studies are in progress to investigate the role of wildlife in the epidemiology of Johne's disease.