Unusual cluster of Mycobacterium bovis infection in cats

BOVINE tuberculosis (TB) caused by Mycobacterium bovis is a major problem in British cattle. Furthermore, M bovis infection has been documented in many other mammals, with badgers acting as an important reservoir and vector of infection for cattle in the west of England and parts of Wales. However, with a few exceptions, the bovine TB epidemic in British cattle has not significantly affected companion animal populations, which are considered ‘spillover’ hosts (Shrikrishna and others 2009, Broughan and others 2013, Gunn-Moore and others 2013). In the seven years (2006/12) since M bovis infection in pet animals became notifiable to the AHVLA, fewer than 30 cats have been confirmed with M bovis each year in Great Britain (Broughan and others 2013, Defra 2013). The vast majority of these cases are sporadic and concentrated in regions of Great Britain where bovine TB is endemic, although a small number of multiple cases in single households have been reported (Monies and others 2000).Between December 2012 and March 2013, seven laboratory-confirmed cases of feline M bovis infection were presented to one small animal veterinary clinic in Newbury, Berkshire, England. A further two suspected cases of M bovis infection were also identified in the same time-frame, but the cats died without further sampling and confirmation of the diagnosis by laboratory culture of the bacterium was not possible. All nine cats belonged to separate households and presented with different clinical pictures, although some common signs were seen. In three cases, one enlarged popliteal lymph node was the principal finding. In two of these, general malaise including anorexia was accompanied by a serosanguinous fluid discharge from the skin overlying the lymph node. Three other cats had a non-healing lesion on a foot (two forefeet and one hindfoot) consistent with having been bitten; most likely …