Dead mouse hopping: Tyzzer's disease in spinifex hopping-mice (Notomys alexis)

Abstract

Tyzzer's disease is caused by Clostridium piliformes and affects a wide range of domestic and wildlife species. Non-descript signs, if any, and a short incubation period make Tyzzer's disease difficult to diagnose and treat before death occurs. Here we describe an unexpected outbreak of Tyzzer's disease in a colony of native Australian spinifex hopping-mice (Notomys alexis). In this study captive hopping-mice were used in a nutrition trial (n=11), and others were housed in close proximity (n=4). During the nutrition trial, two hopping-mice exhibited signs of lethargy and diarrhoea, and were removed from the trial but died soon after. Other hopping-mice exhibited limited clinical signs of ill-health, prior to their death. In total four animals were found dead, and another seven were euthanised, to prevent a potential disease outbreak. Tyzzer's disease was confirmed post-mortem using histopathology silver stain to detect the bacilli-shaped bacteria (C. piliformes) in liver tissue of two hopping-mice. After Tyzzer's disease was confirmed enhanced infection control measures were implemented. Enhanced control measures included the use of metal containers for food and water, sick animals were fed and cleaned last, 5% sodium hypochlorite was used as the cleaning agent, stricter hand washing protocols and a change of gloves between feeding animals, and strict limits on persons entering the facility. Control measures for this disease should include euthanasia of any animals suspected to be infected, complete disinfection of all enclosures and associated equipment using sodium hypochlorite. Molecular methods could be employed to ensure complete removal of bacterial spores prior to new animals being moved into enclosures where affected animals were housed. Tyzzer's disease is a fast spreading disease which can cause detrimental effects to captive colonies and their environment. Captive colonies subjected to stress are at risk of Tyzzer's disease. Appropriate quarantine procedures, close montoring and quick action in response to signs of illness will ensure Tyzzer's disease outbreaks do not occur.

Keywords: Australian native; Captive colony; Clostridium piliformes; Diet change; Murid; Rodent.