A Multicentre Epidemiologic Study of Sudden and Unexpected Death in Adult Cats and Dogs in Australia

SIMPLE SUMMARY: Pets may die unexpectedly, without warning, and with no externally visible reason for death. As in people, postmortem examination can be performed to try to determine the cause of death. There are many diseases which may result in sudden unexpected death in domestic animals, although there is little research on companion animals and no studies performed in Australia. The aims of this study were to identify causes of sudden unexpected death in cats and dogs in Australia by examining postmortem reports and to identify risk factors for certain causes of sudden death. ABSTRACT: Sudden and unexpected death (SUD) is a common reason for animals to undergo post-mortem examination. There is limited literature examining the causes of SUD in cats and dogs, and no research specific to Australia. The purpose of this study was to investigate the epidemiology and pathology of SUD in cats and dogs in a multicentric study across Australia. Retrospective post-mortem reports of SUD in cats and dogs were obtained from four veterinary schools in Australia distributed across four states. The frequency of SUD between institutes ranged from 2.1% to 6.5%. Dogs composed the majority of the study population (76%), and males outnumbered females, particularly in the feline subpopulation. After necropsy, 37% of SUD remained cause unknown, the largest category in both cats and dogs. When cause was identified, cardiovascular disease was most common in both species, followed by gastrointestinal disease in dogs, and trauma in cats. In dogs, multinomial logistic regression identified age as a risk factor significantly associated with the four largest categories of SUD. This study identified causes of SUD in Australian cats and dogs, including novel causes not previously reported. Further, this study revealed a higher rate of unsolved SUD in Australia than can be found in the literature from other countries.