Canine ehrlichiosis in Australia

In May 2020 the tick-borne bacteria Ehrlichia canis was found in a small number of dogs in the Kimberley region of Western Australia, and more recently in dogs from Katherine and near Alice Springs, Northern Territory. This is the first time the infection has been found in Australia in non-imported dogs.

The Consultative Committee for Emergency Animal Diseases is coordinating the national response. To get a better understanding of the possible extent of E canis infection, surveillance is being ramped up in areas of Australia known to have its vector, the brown dog tick Rhipicephalus sanguineus.

Ehrlichiosis in dogs has an acute phase that lasts 2-4 weeks characterised by fever, serous nasal and ocular discharges, anorexia, lethargy and weight loss. Some dogs recover, some remain subclinically infected for an extended period, and some develop the chronic form of the disease (similar signs to the acute phase but more severe).

Veterinarians who see a suspect case should immediately contact the Emergency Animal Disease Watch hotline (1800 675 888) or government vet. They will assist with managing the case and advising on sampling requirements. A full diagnostic work-up is an important component of the surveillance phase.

Further information about ehrlichiosis is available from the WA DPIRD, NT Government, Qld DAF and the Commonwealth Government.

E canis is a potential zoonoses: Dogs do NOT pass the infection to people. However there have been rare cases where people bitten by infected ticks have developed flu-like symptoms in the following 1-2 weeks. Early treatment with an appropriate course of antibiotic should result in a full recovery.

Above: Distribution of the brown dog tick, Rhipicephalus sanguineus (Source: Chandra et al 2020 Ticks and Tick Borne Diseases)