Canine ehrlichiosis is sweeping across Australia

Before 2020, ehrlichiosis—an infectious disease transmitted by ticks carrying a rickettsia—did not exist in Australia. Today, it threatens to infect thousands of dogs, spreading like wildfire across Australia.   More than a thousand dogs have already died since ehrlichiosis first appeared last May in the Kimberley region of Washington State and then in June in Australia’s Northern Territory. Endemic to tropical and subtropical regions worldwide, this is the first time the disease has struck Australia. And already, it is spreading rapidly among many remote Indigenous communities. Most regions are now affected, including Darwin and its surrounding rural areas, Palmerston, Katherine, and others. The bacteria responsible (most commonly Ehrlichia canis) is transmitted to dogs through the bite of a tick (Rhipicephalus sanguineus) and causes fever, lethargy, swollen lymph nodes, subcutaneous hemorrhages, weight loss, and can be fatal. The mortality rate is quite high, particularly among young or elderly dogs and those with compromised immune systems. Bonny Cumming, a veterinarian with Animal Management in Rural and Remote Indigenous Communities (AMRRIC), is concerned. He believes that by the end of the 2020–2021 rainy season, the bacteria could claim thousands of lives among the country’s canine population. Antibiotic treatment is effective against the infection in most cases, but about 10% of dogs still die from it. Veterinarians are urging owners of infected dogs to ensure their pets receive treatment, use effective products for tick control, and limit their dogs’ movements to reduce the risk of spreading the disease. However, the presence of many stray dogs and the difficulty of treating the disease in Indigenous communities are undermining control efforts. This is especially true during the rainy season, when a single female tick can lay up to three thousand eggs. In some regions, you can literally see these mites crawling on walls by the thousands, particularly during the wet season. Coordinated efforts across the entire territory will be essential to control tick populations and hopefully protect dogs exposed to their bites. AMRRC veterinarians recommend, in particular, that stores in at-risk regions be stocked with appropriate animal health products—such as ectoparasiticides for ticks—and that local communities be educated on the signs to watch for in dogs. Let’s hope this is enough to stay out of trouble.