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Preventing the spread of ehrlichiosis in Australia

APVMA grants emergency permit for Seresto to reduce the transmission of Ehrlichia canis to dogs by brown dog ticks

While Covid-19 has dominated our thoughts and headlines over the last year, the arrival of Ehrlichia canis (or “ehrlichiosis”) has been devastating dog populations in northern Australia and is spreading rapidly across the country.

This disease is caused by a bacterium, Ehrlichia canisspread between dogs by the brown dog tick (R. sanguineus). Unlike some other tick-borne diseases, Ehrlichia canis can be transmitted rapidly - within three hours of a single tick bite.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) recently granted an emergency permit to Seresto to help reduce transmission of this notifiable disease.

What is the likelihood of ehrlichiosis affecting and spreading to Australian dogs in densely populated suburbs and cities?

"With the first case of ehrlichiosis in Victoria detected in a dog in June 2021, school holidays in full swing and driving holidays with pets on the rise, the risk of the disease spreading to suburbs and cities is increasing." said Dr Liisa Ahlstrom, Technical Services Veterinarian Elanco Animal Health.

Elanco Veterinarian Olivia Skippings
with puppies in the Northern Territory
"We’ve seen just how rapidly this disease outbreak has spread since the first Australian case was diagnosed in a dog in northern WA in May 2020. 

Since then, over 500 dogs in remote communities of Western Australia and the Northern Territory have tested positive. The true case numbers are likely to be much higher than reported, as many dogs have been found dead without testing or treatment. 

As we are in the midst of the school holidays, we’re imploring pet owners to be vigilant and take simple precautions to ensure that their dogs and others are not exposed to unnecessary risks. This includes ensuring dogs are protected against all five major parasites, especially against ticks which can spread ehrlichiosis, by using products that repel ticks before they bite, and checking pet dogs regularly for ticks, even 2-3 times per day, if they are travelling to high-risk areas. 

Report any symptoms immediately to a local veterinarian. Ehrlichiosis is a nationally notifiable disease and any detected cases must be reported to authorities."

Repelling ticks before they bite is essential

That’s why the APVMA has granted a permit (APVMA PER90869) allowing the Seresto Collar for Dogs to be used to “reduce the transmission of the tick-borne disease caused by the pathogen Ehrlichia canis, thereby reducing the risk of transmission of canine ehrlichiosis between dogs by brown dog ticks”.

"Although there are many highly effective tick products available, most are systemically-acting (i.e. all the chews, tablets and most spot-ons), rely on ticks biting the dog and feeding on blood to receive a lethal dose of active ingredient, and kill ticks too slowly to stop transmission of disease." said Dr Liisa Ahlstrom, Technical Services Veterinarian Elanco Animal Health.

"However, all products that effectively kill brown dog ticks do have a role to play in helping to contain this disease outbreak at a population level, by reducing the numbers of the brown dog tick vector. But it’s important to make it clear, that only a topically-acting product that repels ticks to stop them biting, like Seresto, is able to protect dogs from becoming infected."

How does the Seresto collar work?

Elanco Veterinarian Dr Liisa Ahlstrom 
in NT explains how to use Seresto

Seresto for Dogs is a long-lasting, water-resistant collar containing imidacloprid and flumethrin that repels ticks and kills fleas and ticks on contact, and reduces the transmission of tick-borne diseases, including ehrlichiosis.

"The unique polymer matrix of Seresto enables release of controlled doses of two proven active ingredients: imidacloprid, a very potent insecticide, and flumethrin, a highly potent acaricide." explains Dr Liisa Ahlstrom

"The innovative polymer matrix stores the active ingredients in the collar itself. The inclusion of neutral oils in the collar matrix allows for the migration of active ingredients from the collar matrix to the surface of the collar to form a micro-layer. This migration is controlled by a concentration gradient between the collar matrix and the collar surface – once their concentrations are balanced, further release of active ingredients stops. 

Assisted by the collar’s neutral oils, the active ingredients transfer from the micro-layer on the collar surface into the natural lipid layer of the dog’s skin and hair. The active ingredients spread via diffusion over the body surface within the lipid layer. The depletion of active ingredients from the collar surface to the dog’s lipid layer triggers further migration of actives (along their concentration gradient) from the collar matrix to the collar surface, to restore the concentration equilibrium. 

As a result, active ingredients continue to migrate from the collar matrix to the collar surface only as needed, ensuring low-dose protection is sustained for up to 8 months for fleas and 4 months for ticks in dogs."

Studies have shown that Seresto also reduces the transmission of Ehrlichia canis in dogs. This is a registered product claim in other countries.

For more details about Ehrlichiosis, you can contact your State Veterinary Authority, the National Pest and Disease Outbreaks website (, the AMRRIC - Animal Management in Rural & Remote Indigenous Communities website (

For information about Seresto for Dogs, contact Elanco on Tel (02) 9878 7777 or visit the Advantage Pet Care website.

Image Source (lead image) - AMRRIC: puppy suspected of having ehrlichiosis


Related Topics:

Victoria detected the first case of the dog disease ehrlichiosis


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