Ehrlichiosis

Ehrlichiosis is a tick-borne disease affecting dogs and foxes, and on rare occasions, humans or cats.

Ehrlichiosis, also referred to as canine monocytic ehrlichiosis (CME), is caused by Ehrlichia canis, an intracellular bacterium transmitted by the brown dog tick. Ticks acquire E. canis by feeding on infected dogs and then transmit the infection when they feed on other dogs. The organism infects cells in the immune system of dogs.

Symptoms of disease can vary and are generally non-specific, so cases of ehrlichiosis may appear similar to other illnesses.

There is no vaccine against E.canis however, if treated early, antibiotics may assist in curing the disease. Tick control is the main preventative measure against the disease.

On rare occasions, humans may become infected with E.canis through the bite from an infected tick. Dogs cannot directly transmit infection to people.

Everyone has a role in protecting our pets from E.canis by carefully monitoring the health of their pets, seeking professional advice if illness is detected and notifying Agriculture Victoria.

Current situation

In May 2020, a small number of dogs from the Kimberly region of northern Western Australia were confirmed as infected with Ehrlichia canis.

The Department of Primary Industries and Regional Development (DPIRD) in Western Australia is working with private vets to manage the dogs.

Investigations into the origin of the infection are ongoing with no obvious leads at the present time.

Western Australia will conduct further surveillance to determine the extent of ehrlichiosis in the Kimberley region and put containment measures in place.

This is the first time ehrlichiosis infection has been detected in dogs in Australia that have not been imported. Victoria responded to E.canis detections in 2016 and 2018 in imported dogs.

Human health

On rare occasions humans can get ehrlichiosis through the bite of an infected tick.

Dogs cannot transmit E.canis directly to people.

Clinical signs of human ehrlichiosis include fever, headache, eye pain and gastrointestinal upset.

If you are concerned you have been exposed to infected ticks/E.canis you should seek medical advice, i.e. general practitioner or local hospital.

Disease information

Ehrlichiosis is a disease caused by the intracellular parasite, E.canis. It is transmitted by the brown dog tick (Rhipicephalus sanguineus) which becomes infected after feeding on an infected dog. Ticks can remain infectious for up to 5 months.Close-up photo of a brown dog tick

Although brown dog ticks are generally associated with tropical and subtropical environments, this species is unusual in that it can complete its entire life cycle indoors, thereby potentially allowing it to survive in colder climates.

Ehrlichia is maintained in cycles between ticks and either wild or domesticated animals in the family Canidae including dogs and foxes. It is not clear if dingos are also viable hosts for the tick.

Clinical findings in dogs with ehrlichiosis vary with the phase of the infection. During the acute phase, nonspecific signs such as fever, nasal discharge, anorexia, weight loss, and difficulty in breathing may occur. Later, signs may include depression, weight loss, pale mucous membranes, abdominal pain, bleeding, enlarged lymph nodes and stiff, swollen, painful joints. Eye abnormalities may also occur.

German Shepherds are reportedly particularly susceptible to the chronic phase with the development of a severe and often fatal haemorrhagic condition known as tropical canine pancytopenia.

There is no vaccine for E canis infection, but antibiotic treatment is possible and may provide a cure if the dog is treated early enough. Severe, chronic or complicated cases may need a long course of treatment and the dog may never be fully cured.

Tick control remains the main preventative measure against the disease.

Information for pet owners

Pet owners are encouraged to carefully monitor the health of their animals and seek veterinary advice if there is any suspicion of illness.

If you are travelling into tick-prone areas, (particularly northern Australia) treat your pet with an effective tick control product recommended by your veterinarian and regularly check your pet’s coat, feet, ears and anal region for the presence of ticks.

Subsidised disease investigations

Agriculture Victoria provides subsidised disease investigations to pet owners for detections of suspect emergency animal diseases. Contact your local District Veterinary Officer at Agriculture Victoria or your private veterinarian for eligibility criteria and approvals.

See Significant disease investigation program.

Information for veterinarians

If you suspect an exotic or emergency animal disease, immediately contact your local Agriculture Animal Health and Welfare office or the all-hours Emergency Animal Disease Hotline 1800 675 888. You can also use the Notify Now smart phone app for less urgent notifications.

Significant Disease Investigation (SDI) Program

The Victorian Significant Disease Investigation (SDI) Program aims to boost Victoria's capacity for the early detection of emergency animal diseases in animals by increasing the participation of veterinary practitioners and subsidising the cost of investigating significant diseases.

For further information on the eligibility criteria, subsidies and approvals process see, see Significant disease investigation program.

Investigating suspect E.canis cases

Veterinarians investigating animals suspicious of E.canis should contact Agriculture Victoria immediately using the EAD Hotline on 1800 675 888, the Notify Now app or their local District Veterinary Officer.

Diagnostic samples required from suspect cases include:

  • From the affected dog – whole blood in plain (red top) or clot tubes (gold top), and a blood sample into a heparin or EDTA vacutainer.
  • Ticks may be submitted in alcohol and will be identified before undergoing testing.

Agriculture Victoria will advise on sample transport requirements and any additional activities required.

Additional resources

Media releases

Page last updated: 13 Jul 2020