This presentation will discuss the causes of emerging infectious diseases in small animals and will focus on recent discoveries of new and introduced vector-borne infections in Australia. Canine monocytic ehrlichiosis, caused by Ehrlichia canis and transmitted by the brown dog tick, was detected in dogs living in northern Western Australia in May 2020, and represents a serious threat to the Australian canine population, especially in tropical and subtropical regions where the vector tick is abundant. Canine hepatozoonosis was discovered in a small number of dogs, all Maremma sheepdogs or their crosses, in central Queensland. Other novel piroplasms, potentially able to infect dogs and cats, have also been described in wildlife ticks removed from companion animals. These example remind veterinarians in practice about the importance travel history, proactive ectoparasite prophylaxis and to remain vigilant for unusual disease presentations.
Emerging infectious diseases can have major impacts on wildlife including causing severe decline and extinction. For potentially emerging pathogens, sufficient data on prior absence (or a prior difference in disease dynamics) are frequently lacking for wildlife. Improved surveillance, particularly for neglected host taxa, geographical regions and infectious agents, would enable more effective management should emergence occur. Exposure to domestic sources of infection and human-assisted exposure to exotic wild sources were identified as the two main drivers of emergence across host taxa; the domestic source was primary for fish while the exotic wild source was primary for other taxa. There was generally insufficient evidence for major roles of other hypothesized drivers of emergence.