Introduction

Rabbits are asymptomatic carriers of Mycobacterium avium subsp paratuberculosis (Map) and shed sufficient numbers of bacteria in their faeces so that one faecal pellet may constitute an infective dose for cattle. This leads to a high risk of infection via the faecal-oral route in grazing environments, considered to be the main route of Map transmission, especially as cattle do not avoid rabbit faeces while grazing. The spatial and temporal dynamics of paratuberculosis in rabbits were studied with the overall aim of determining environmental patterns of infection and thus risk of inter-species transmission to livestock.

Methods

Rabbits were sampled monthly between April 2002 and May 2003 from a study site in Perthshire, Scotland, where Map had previously been isolated from cattle, sheep and rabbits. Gross examination of the samples was carried out before tissues were collected for microbiological and histopathological examination. Isolates of Map were confirmed by PCR using IS900.

Results

Overall prevalence of Map in rabbits was 39.7%; temporal distribution of infection in rabbits followed a cyclical pattern with a peak in Spring of 55.4% and a low in Summer of 19.4%. Spatially, Map infected rabbits, and thus risk of inter-species transmission, were highly clustered in the environment. However, this was largely due to the distribution of rabbits in the environment.

Discussion

Knowing the spatial distribution and seasonal variance in prevalence of paratuberculosis in rabbits can inform livestock management practices in order to reduce the risk of inter-species transmission.