NORTHERN TERRITORY VETS SUSPECT EXOTIC TICK-BORNE DOG DISEASE HAS GONE UNDETECTED ‘FOR YEARS’

An exotic disease potentially fatal to dogs has recently been confirmed in northern Australia for the first time, with multiple cases reported in the Northern Territory and West Australia’s Kimberley and Pilbara regions.

However, some NT veterinarians suspect the disease may have avoided detection and circulated in the state’s ticks and dogs for years.

Ehrlichiosis is a tick-borne illness caused by the bacterium, Ehrlichia canis, which occurs worldwide and is most common in tropical and sub-tropical regions.

Symptoms in infected dogs include fever, lethargy, enlarged lymph nodes, loss of appetite and weight loss, and if left untreated, ehrlichiosis can be fatal.

Australia’s first domestic outbreak was found in dogs from the WA towns of Halls Creek and Kununurra in May, and further cases have today been confirmed in WA’s West Kimberley and Pilbara regions.

NT Chief Veterinary Officer, Sue Fitzpatrick, said cases of ehrlichiosis were also confirmed in five dogs from the NT town of Katherine and a remote community west of Alice Springs last week.

Dr Fitzpatrick said the prevalence of the disease was difficult to determine, because its symptoms were similar to other well-established tick-borne diseases, such as anaplasmosis and babesiosis.

Under the radar

Dr Fitzpatrick said the disease might have gone undetected for a long time.

“Some vets believe they’ve seen symptoms like this in NT dogs for a number of years,” she said.

One such vet is Peter Trembath, owner of Katherine Vet Care Centre, who believes he has been treating Ehrlichiosis in NT dogs as far back as the 1990s.

Mr Trembath has previously worked as a vet in Zimbabwe, where ehrlichiosis is endemic.

“Also, unexplained bleeding postoperatively of dogs, so say you do a routine castration, and the animal bleeds a lot despite compression and any other treatments.

“It has probably just flown under the radar.”

The disease is maintained by a cycle of transmission between ticks and dogs and cannot be passed from infected dogs to humans or other dogs.

Dog disease testing

In 2001, a survey of 316 domestic dogs from Townsville, Cairns, Darwin, Kununurra and Broome, found no presence of ehrlichiosis.

Dr Fitzpatrick said similar surveys, as recent as 18 months ago, also found no evidence of ehrlichiosis in the sampled dog populations.

However, she did not rule out a historical and undetected presence of the exotic disease.

If vets had seen symptoms of ehrlichiosis for years, then why was it not tested for and discovered sooner?

The answer may be related to the financial cost of testing.

Sam Phelan is the veterinarian for the Roper Gulf Regional Council, a local government covering 186,000 square kilometres of the NT.

She said, in the past, the cost of testing and the absence of Australian cases could have thwarted an earlier detection.

“You tend to query what you already know, and then you will stumble upon these sorts of diseases,” Dr Phelan said.

Check your dogs for ticks

Dr Fitzpatrick said free testing for ehrlichiosis was made available in 2019 after it was added to the national notifiable disease list.

“My understanding is that ehrlichiosis, due to Ehrlichia canis, became more prevalent in neighbouring countries so it was considered an important disease that may actually enter into Australia,” she said.

Researchers are also working to improve testing methods for ehrlichiosis.

The NT Government has a community awareness and surveillance program for the disease in NT dogs, which includes free diagnostic testing at Berrimah Veterinary Laboratories.

A surveillance program will determine just how widespread the disease is, and how long it has been circulating in Northern Australia.

Dr Fitzpatrick said NT dog owners should check their dogs for ticks daily, avoid tick-infested areas, and maintain a tick treatment program.