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Ehrlichiosis In Dogs: Symptoms and Treatment

Due to its tricky name, Ehrlichiosis might not be the most talked about of the tick-borne diseases, but it’s one that pet owners should be aware of. Due to the prevalence of brown dog ticks, which spread Ehrlichiosis, it’s a condition that can be found worldwide, affecting dogs, cats, and humans.

What is Ehrlichiosis?
Ehrlichiosis is a condition caused by infection with the Ehrlichia bacterium. The bacteria are transmitted from host to host by feeding ticks, primarily the brown dog tick. After an incubation period of 1-3 weeks, the infected animal may begin to display clinical symptoms, representing the start of the acute phase of the disease. The bacteria primarily affect the white blood cells, where it destroys the platelets that assist with blood clotting but can also impact the lymph nodes, bone marrow, liver, and spleen.

There are actually a number of strains of the Ehrlichia bacteria, but the most common cause of Ehrlichiosis is Ehrlichiacanis. Less common is the Ehrlichiaewingii strain. The disease is easily transmitted to both dogs and humans but occurs less frequently in cats.

Risk factors

Ehrlichiosis is transmitted when a tick infected with the Ehrlichia bacterium feeds on another animal, so the risks of Ehrlichiosis are directly related to your pet’s exposure to ticks and tick bites. Ehrlichiacanisin particular is predominately spread by the brown dog tick (Rhipicephalus sanguineus), but the Lone Star tick (Amblyommaamericanum) can transmit the Ehrlichiaewingii bacterium, which causes a less common form of Ehrlichiosis.

Brown dog ticks are found worldwide, but more commonly in warmer climates. Unlike other ticks that prefer wooded or grassy outdoor areas, brown dog ticks most frequently live in or around the house and yard, which is why they are also known as ‘kennel ticks’. Infestations of brown dog ticks can be found behind baseboards, in furniture and even on curtains.

Symptoms of Ehrlichiosis

Canine Ehrlichiosis has three separate stages, but your dog may not necessarily progress through all stages. Any breed of dog can become infected after the initial tick bite and therefore experience the acute stage, but some breeds are more prone to advancing to the chronic stage of the disease, particularly German shepherds and Doberman pinschers.

Acute stage – this is the initial phase of the disease, which usually presents 1-3 weeks after the initial infection and can last for several weeks. During this stage, your dog may experience fever, abnormal bleeding and bruising, lethargy, anemia and inflammation of the eyes.

Subclinical stage – dogs that are not cleared of the infection in the acute stage will then pass into the subclinical stage. Although this phase of the disease has no outward symptoms, the dog is still infected and if tested will show a low blood platelet count. This phase may last months or even years without passing into the chronic stage.

Chronic stage – this is the final and most problematic phase of Ehrlichiosis. Symptoms in this stage often include those in the acute stage, but become more serious and harder to treat. In addition, your pet may experience chronic eye problems, neurological issues, and kidney disease. Chronic Ehrlichiosis can be fatal.

Diagnosis

Your vet will base their diagnosis on both the clinical symptoms and blood tests, however, the disease is not always easy to diagnose.

The blood test checks for antibodies to Ehrlichiacanis, which can take 2-3 weeks to develop in the body, so dogs in the early stages of the disease may produce a false negative test. In this case, the test may need to be repeated at a later date. Additionally, this test will only indicate if the dog has been exposed to the bacteria. A dog may develop these antibodies but never show any clinical signs of the disease and will not require treatment.

To further complicate the diagnosis, the ticks that spread Ehrlichiosis also transmit the bacteria that cause other conditions such as Lyme disease and Rocky Mountain Spotted Fever.

Treatment

Treatment for Ehrlichiosis consists of an antibiotic to clear the infection, which your dog will need to take for 3-4 weeks. The most common antibiotic prescribed is doxycycline, but tetracycline is also used.

Dogs in the chronic stage of the disease, or who experience severe symptoms in the acute stage, may also require supportive care. This can include intravenous fluids for dehydration, blood transfusions for anemia and steroids when the low platelet count has become life-threatening.

Prognosis

As with many diseases that are caused by bacteria, early diagnosis and treatment is key to a successful recovery. For dogs in the acute stage of the Ehrlichiosis, the prognosis is good, with many animals seeing an improvement in symptoms within a few days of starting treatment.

Animals that do not clear this acute stage of infection may pass into the subclinical phase. As a general rule, the longer an animal is infected with the bacterium, the harder it is to get rid of. The subclinical phase can last for months or even years. During which time your pet will not display any outward signs of Ehrlichiosis, although their bloodwork will show an abnormal platelet count.

For dogs that progress to the chronic stage of the disease, the prognosis is less positive. Where chronic Ehrlichiosis has caused low blood cell levels due to bone marrow suppression, the animal may no longer respond to treatment, and the disease may prove fatal.

Preventing Ehrlichiosis

There is no vaccine medication available that will prevent your pet from being infected with the Ehrlichia bacteria. As the disease is usually spread by tick bites, reducing exposure to ticks and preventing tick bites is the only way to avoid the disease.

Animals do not develop any long-lasting immunity after being infected so even dogs that have previously contracted Ehrlichiosis can be affected again if exposed to the bacteria.

Unlike other ticks, the brown dog ticks that spread Erhclichiosiscan complete their entire lifecycle indoors. Therefore checking yourself and your pet for ticks after returning from a walk may not suffice in preventing exposure to ticks. As well as regular vacuuming indoors and keeping the yard tidy, it is recommended to protect your pet with a medicated tick treatment.

The particular tick preventative you use will depend on your dog's age, size, and any other special needs. Oral or topical medications such as NexGard or Frontline Plus usually need to be administered monthly to provide continued protection against ticks. The Seresto collar provides protection against ticks for up to 8 months, but may not be suitable for pregnant animals or households with children. To discover the right tick preventative for you and your pet, refer our treatment comparison chart.