Ehrlichiosis in Dogs

Currently as of early 2023, the disease has been reported in the Mount Isa area and as far east as Townsville.

All people travelling with dogs into north Queensland, the Northern Territory, the far north of Western Australia and northern South Australia should be taking precautions against ticks.

All dogs should have Serresto tick collars on prior to entering these areas and to stay on tick preventatives for several weeks following. If you are using other oral products for flea, heart worm and tick control, these can continue to be used. The aim is to prevent the tick from biting the dog and these collars repel the ticks.

Ehrlichiosis is a tick-borne disease affecting primarily dogs but equally affects dingoes and foxes. It is not transmitted from dog to dog, transmission only occurs through infected ticks, the main one being the brown dog tick.

The brown dog tick is widespread throughout mainland Australia. No brown ticks have been found in Tasmania. While some ticks are mostly coastal, the brown dog tick is found extensively throughout the Australian continent.

Ehrlichiosis is the disease that is caused by a tick-borne bacteria called Ehrlichia Canis. Once a dog has been bitten by an infected tick, there are 3 stages of infection:

1. Acute or early phase (3-4 weeks)
2. A subclinical phase (months to years)
3. Chronic or long-term stage. (months to years)

Symptoms include fever, lethargy, enlarged lymph nodes, loss of appetite, discharge from the eyes and nose, weight loss, anaemia, and bleeding disorders such as nosebleeds or bleeding under the skin that looks like small spots, patches or bruising.
The severity of symptoms varies considerably between dogs. The incubation period is 1-3 weeks after the tick bite, but the chronic form may not manifest for months or years following infection. PCR and ELISA tests give the most accurate diagnosis along with comprehensive blood tests. Affected dogs require veterinary treatment and supportive care, the earlier this is diagnosed and treated the better. Usually, these dogs are treated with tetracycline drugs for a minimum of 4 weeks, shorter treatment periods may result in subclinical carriers. Seronegative PCR tests will indicate if the infection has cleared.
If not properly treated these dogs can and do die.

Distribution

This disease can be found worldwide, particularly in tropical and subtropical areas. Once the disease is in the brown dog tick population, it is very difficult to control. German Shepherds and Siberian Huskies are predisposed to develop more severe signs of disease with a worse prognosis (reduced cell-mediated immune response).
In extremely rare cases, infected ticks may infect people, however the species of Ehrlichia that affects humans have not yet been detected in Australia.

Ehrlichiosis is currently a notifiable disease. While this disease was first reported in the far north of Western Australia in the middle of 2020. Since that time, cases have also been found throughout the Northern Territory where it is now considered endemic, right down to the South Australian border. A case has been found recently in Mount Isa where the infected dog has no history of ever leaving the state.
At the rate this is moving, no state will be safe and all people who travel with their dogs should be aware of the risks and the need to provide preventative measures to protect their dogs.

Dogs from affected areas are being monitored and their movement limited (at this stage). Dogs (including rescue dogs) moving out from these areas are required to test negative. Healthy dogs should be on an effective tick control program.

Prevention

The aim is to prevent tick bites in the first place so as to avoid the dog getting the disease. The best prevention is to use Tick collars of which Serresto is the best as it repels ticks.

Secondly, have a good tick and flea control program in place so that if a tick does get on the dog, it will be killed. There are quite a few products that can be used but ensure the dog is not left unprotected by running late with treatments.

Avoid taking dogs into tick infected areas such as bush and long grass, particularly in coastal areas. Inspect your dogs daily for ticks for 5-6 days after being in tick infected areas.

Check bedding and treat with anti-parasite sprays if in a tick area.

Travelling

The most likely way this disease will spread is by the transport of dogs interstate. Dog exhibitors like to travel far and wide for shows, often interstate. We should all be vigilant with providing tick control measures and renewing these before we travel!

Do not take dogs running along beaches, through the bush etc without adequate tick prevention. Be aware at some shows, the grounds may back onto bush, do not walk your dogs through these areas.

Long Term

At the rate this disease Is spreading, it is highly likely that this disease will be widespread throughout Australia within the next 5-10 years. With global warming, the brown ticks will become more common even in the southern states. Keep an eye on warnings put out by the Government of where new cases are detected so you can be aware of this real threat to your dogs health.

Tick prevention should become second nature, especially when travelling into areas of high risk.

Dr Karen Hedberg BVSc
Dogs Australia Canine Health & Wellbeing Committee Chairperson
1 March 2023