Canine monocytic ehrlichiosis in Victoria – Biosecurity advisory

Biosecurity Advisory banner

Date of issue: 16 June 2022

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

Canine monocytic ehrlichiosis (infection with Ehrlichia canis bacteria) has spread across Australia since the initial cases were detected in Western Australia in May 2020.

On 18 June 2021, the first case of the disease was detected in Victoria.

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 showed no clinical signs but returned positive results on both the TaqMan 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.

The easiest ways to do this are to contact your Agriculture Victoria District Veterinary Officer directly or through the Customer Contact Centre on telephone 136 186.

Please remember 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
Limb and body oedema

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

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

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

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

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 it has travelled from/to one since 1 January 2020. Veterinary practitioners can also discuss submitting samples from cases that are clinically highly suggestive of E. canis but without an interstate travel history, with their District Veterinary Officer.

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 initial testing of suspected cases that have been discussed with, and approved by, your District Veterinary Officer.

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 an 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.

Unfortunately, there is no straightforward test to monitor treatment success. Follow-up testing is not subsidised by Agriculture Victoria and if such testing is undertaken it will be at the owner’s expense.

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.

Canine monocytic ehrlichiosis in Victoria – Biosecurity advisory

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

Investigating suspected E. canis cases

Treatment and prevention

E. canis is potentially a zoonotic agent on rare occasions

Further reading and more information