First case of canine monocytic ehrlichiosis (infection with Ehrlichia canis) detected in Victoria

The Chief Veterinary Officer of Victoria issued the following Biosecurity Advisory on 23 June 2021

On 18 June 2021, the first case of canine monocytic ehrlichiosis (infection with Ehrlichia canis bacteria) was detected in an Australian-born dog in Victoria.

The disease has now spread across Australia since the initial cases were detected in Western Australia in May 2020 with the ACT now the only State or Territory not having recorded a case in an Australian dog.

The infected dog originated from the Northern Territory, where the disease is established, and was rehomed to north-west Victoria in mid-2020. The dog is showing no clinical signs but returned positive results on both the TagMan Assay polymerase chain reaction (PCR) and immunofluorescence antibody (IFA) tests. The PCR test detects the disease agent and IFA test detected antibodies (non-protective).

Canine monocytic ehrlichiosis (CME) is a nationally notifiable disease so veterinarians who suspect this condition must report it immediately.

The easiest ways to do this are to contact your local Agriculture Victoria Senior Veterinary Officer directly, through the Customer Contact Centre on telephone 136 186, or by ringing the all-hours Emergency Animal Disease Watch Hotline on 1800 675 888.

Please be reminded to consider ehrlichiosis as a differential disease for dogs presenting with the following clinical signs:
  • fever
  • lethargy
  • corneal oedema
  • conjunctivitis
  • haemorrhagic ocular changes
  • epistaxis and bleeding disorders, and
  • limb and body oedema.

This is especially important when the dog originated from (such as adopted dogs) and/or has recently travelled to high risks areas being the Northern Territory, northern Western Australia, and northern South Australia.

Be vigilant when dog owners are grey nomads, holiday makers or workers returning home to Victoria.

Acute, sub-clinical and chronic phases of ehrlichiosis are recognised.

Less common but recognised clinical signs include anorexia and weight loss, muscle pain and stiffness, polyarthritis, splenomegaly, lymphadenomegaly, vestibular disease and seizures.

Investigating suspected E. canis cases

Suspected cases are those where a dog is showing clinical signs consistent with ehrlichiosis and either originated from a jurisdiction outside of Victoria or have travelled from/to one since 1 January 2020. Veterinary practitioners can also discuss submitting samples from cases that present differently with their SVO.

It is important to note, at this time, that there will be no test cost to the veterinary practitioner, the veterinary practice or the client (dog owner or carer) to submit blood samples for E. canis infection testing and tick identification (if found) for suspected cases. Samples required are:
  • From the affected dog – a whole blood sample in a plain (red top) or clot tube (gold top), and a blood sample in an EDTA tube.
  • If ticks are found on the dog and/or its surroundings, collect these in a clean resealable bag or sample container and freeze prior to submission.

Agriculture Victoria will advise on sample transport requirements to the Veterinary Diagnostic Services at AgriBio and any additional activities required.

Dogs are currently not included in the Victorian Significant Disease Investigation (SDI) Program so private veterinary practitioners will not receive a subsidy for E. canis investigation.

Treatment and prevention

  • The antibiotic doxycycline is the recommended treatment for ehrlichiosis and supportive treatment may be considered as indicated.
  • There is no vaccine for ehrlichiosis.
  • Infection can occur within hours of brown dog tick bites. Tick collars and spot-on products that kill and repel ticks can provide primary protection, in combination with tablets and chews registered for tick control.
  • Dog owners or carers are encouraged to seek veterinary advice for their dogs’ general care and wellbeing but particularly when their dogs are unwell.

The Northern Territory Government has produced comprehensive guidelines for veterinarians.

E. canis is potentially a zoonotic agent on rare occasions.

The disease cannot be directly passed from infected dogs to humans. On rare occasions humans can become infected through the bite of an infected tick. People should seek medical advice if they feel unwell after being exposed to ticks.

Further reading and more information

For further information please see the Agriculture Victoria website – Ehrlichiosis