This article is sponsored content brought to you by Elanco.
Seresto™ for Dogs is a long-lasting, water-resistant collar containing imidacloprid and flumethrin that works on contact to repel and kill ticks, and reduces the transmission of tick-borne diseases.
Four years after its initial discovery in Australia, the life-threatening disease canine monocytic ehrlichiosis (CME) is now widely disseminated across northern Australia. Worryingly, CME is increasingly diagnosed Australia-wide in dogs that have travelled to high-risk areas.
CME is caused by the bacterium Ehrlichia canis (E. canis), transmitted by the brown dog tick Rhipicephalus linnaei (recently renamed from R. sanguineus).
Veterinarians throughout Australia should be very concerned about CME, not only because of its welfare implications, but because it now needs to be included on the differential diagnosis list for many medical problems in dogs, ranging from unexplained fever, bleeding diatheses and bone marrow disease.
Recent research has confirmed not only that there has been a southwards expansion of the brown dog tick’s geographical range, but also that the brown dog tick strain here – R. linnaei – is the most effective strain for maintaining the life cycle of E. canis. Worse, the tick is also well adapted to indoor living and readily establishes within kennels or homes, and even in cooler climates.
E. canis is injected into dogs within 3 hours of tick attachment. This is critical with respect to preventing dogs from becoming infected (see below). In the bloodstream, E. canis is taken up by monocytes where it multiplies rapidly, spreading throughout the body, and causing clinical signs that are first observed about two weeks after transmission.
The acute phase of the disease is characterised by fever, anorexia, lethargy, ocular signs (conjunctivitis, corneal oedema, uveitis), and bleeding tendencies, such as nose bleeds and widespread petechiae. Dogs that survive this stage of infection progress to a subclinical phase that can last many months or even years.
One of the most serious, chronic phase effects of this disease, is on the bone marrow with a frequently fatal outcome. Dogs die of septicaemia as they can no longer fight off even the most innocuous of infections, or they bleed uncontrollably.
Clinical suspicion for CME should be increased in dogs with recent tick exposure or travel history, in dogs with pyrexia and other aforementioned clinical signs, or in dogs with unusual haematological and biochemical disturbances.
A confirmed diagnosis requires specific testing that demonstrates the presence of E. canis in the sample being tested (usually blood). This is achieved most readily by PCR, available from most laboratories, sometimes as part of a “tick” or “anaemia” panel.
When treated with antibiotics and other supportive measures, most dogs will recover, however some do not respond, and may progress to develop a terminal persistent-to-chronic infection. Doxycycline is the drug of choice and is recommended to be given continuously for 28 days. Whilst most dogs will quickly become PCR negative in blood samples, the bacterium may be sequestered in spleen or bone marrow resulting in persistent infection.
E. canis can be transmitted within 3 hours of tick attachment, which is faster than most tick products can kill ticks. Therefore, to prevent disease transmission, it is critical to stop ticks biting. Seresto™ for Dogs is a long-lasting, water-resistant collar containing imidacloprid and flumethrin that works on contact to repel and kill ticks, and reduces the transmission of tick-borne diseases, including anaplasmosis, babesiosis and ehrlichiosis for 4 months.
Although isoxazolines kill ticks too slowly to effectively prevent transmission of E. canis, they help break the cycle of disease by stopping an infected dog from being a source of infection.
Read product label for full directions.
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