Ehrlichia canis (E. canis) is a type of bacteria that infects dogs, leading to a disease known as ehrlichiosis. This condition is a significant concern for dog owners globally, especially where ticks are prevalent. The bacteria are found across various continents, including North and South America, Asia, and Africa.
How E. canis is Transmitted
The primary way E. canis is transmitted to dogs is through the bite of an infected brown dog tick. This tick species is the main carrier of the Ehrlichia organism in nature. The bacteria are passed from the tick to the dog during a blood meal, typically requiring the tick to feed for 24 to 48 hours for transmission.
Once an infected tick attaches, the E. canis bacteria are transferred through its saliva into the dog’s bloodstream. While the brown dog tick is the most common vector, other tick species can occasionally transmit related Ehrlichia species to dogs.
Symptoms of Ehrlichiosis
Ehrlichiosis caused by E. canis typically progresses through three distinct phases, each presenting with different clinical signs.
Acute Phase
The initial stage, known as the acute phase, usually appears one to three weeks after an infected tick bite. During this period, dogs may exhibit fever, lethargy, and a reduced appetite. Swollen lymph nodes, weight loss, and occasionally bleeding disorders like nosebleeds or unusual bruising can also be observed. This phase generally lasts between two to four weeks.
Subclinical Phase
Following the acute phase, dogs may enter a subclinical phase, which can last for months or even years. In this stage, the dog often appears outwardly healthy, even though the bacteria remain present within their body. Blood tests during this period might reveal subtle changes, such as a slightly low platelet count. Not all dogs will progress to the final stage, as some may manage to clear the infection.
Chronic Phase
If the dog’s immune system does not successfully eliminate the infection, the disease can advance to the chronic phase, which is often more severe. Dogs in this stage may experience significant weight loss, persistent anemia leading to pale gums, and recurrent bleeding episodes. Eye inflammation, also known as uveitis, and neurological signs like disorientation or unsteadiness can also develop. This long-standing infection can lead to more widespread organ damage.
Veterinary Diagnosis and Treatment
When a dog owner suspects ehrlichiosis, a veterinarian will typically begin with a thorough physical examination and review the dog’s history, including any potential tick exposure. Diagnostic confirmation primarily relies on specific blood tests. Common in-clinic screening tools include the SNAP 4Dx Plus test, which can detect antibodies to E. canis and related tick-borne agents. A positive result on this screening test indicates exposure, prompting further investigation.
More definitive diagnostic methods include Polymerase Chain Reaction (PCR) tests, which detect the bacteria’s DNA, and antibody titers, which measure the level of specific antibodies in the blood. PCR testing can be particularly useful in the early stages of infection when antibody levels may not yet be high. Antibody titers can remain elevated for months or years after an infection, even after successful treatment, so interpretation considers the dog’s clinical signs.
The standard treatment for ehrlichiosis is a course of antibiotics, with doxycycline being the most commonly prescribed medication. This antibiotic is typically administered for a minimum of 28 days, though the duration can vary based on the severity of the infection and the dog’s response. In more severe cases, particularly those involving significant anemia or bleeding, supportive care such as blood transfusions may be necessary to stabilize the dog’s condition.
Preventing Tick-Borne Diseases
Preventing tick-borne diseases like ehrlichiosis involves a consistent and multi-faceted approach throughout the year. Utilizing veterinary-recommended tick control products is a primary defense. These products are available in various forms, including oral medications, topical spot-on treatments, and tick collars. Each type works to either kill or repel ticks, reducing the chance of transmission.
Beyond pharmaceutical prevention, environmental management plays an important role. Keeping grass short, removing leaf litter, and trimming bushes around the property can help reduce tick habitats. Regular physical checks of your dog are also highly recommended, especially after they have spent time outdoors. Running your hands over your dog’s coat and feeling for small bumps allows for early detection and prompt removal of any attached ticks.