Meningitis cause of abnormal behaviour in Roe deer

At the beginning of June 2017 a roebuck in the province of Utrecht was spotted behaving oddly; the animal showed no flight response and stood still rather than fleeing when approached. The animal was euthanised by a nature warden and submitted to the DWHC for post-mortem exam.

The deer was covered in ticks and botfly larvae were found in the nostrils and ears. Barber’s pole worms were found in the abomasum (fourth stomach). Microscopic investigation showed that the animal had a purulent meningitis and microbial culture identified the bacteria Trueperella pyogenes. This condition is likely to explain the altered behaviour of this animal.

The bacteria Trueperella pyogenes, previously called Arcanobacterium pyogenes can cause purulent infections anywhere in the body. It is an opportunistic bacteria, entering the body via a wound, and typically causes problems in weakened animals. In the case of the roebuck it is possible that the bacteria were able to enter the body via fight wounds, or damage caused to the mucuos membranes by the botfly larvae, erupting teeth or abrasive forage. Similar wounds in the mouth may lead to infection with Actinomyces bacteria, although a Swiss study showed that such lesions were more frequently associated with Trueperella pyogenes.

Trueperella infection only occurs occasionally and is not a threat to the roe deer population. The bacteria is not zoonotic (i.e. is not transmitted from animals to humans). Cattle can be infected by this bacteria although infection is not via contact with infected roe deer; the bacteria is transmitted by a species of fly known as the sheep headfly (Hydrotea irritans) and typically causes mastitis. More information about Trueperella infection in cattle can be found at the Dutch Animal Health website (in dutch).


  • Gezondheidsdienst voor dieren, 2012. Zomerwrang: Arcanobacterium wordt Trueperella pyogenes.
  • Pewsner, P., F. C. Origgi, J. Frey & M-P. Ryser-Degiorgis, 2017.  Assessing Fifty Years of General Health Surveillance of Roe Deer in Switzerland: A Retrospective Analysis of Necropsy Reports.  PLoS ONE 12(1): e0170338.;
  • Williams, E.S. & I. K. Barker (red), 2001. Infectious Diseases of Wild Animals. Third edition, 2001.  Iowa State University Press / Ames.