Check dogs for ticks to prevent Ehrlichiosis

Shana Bohac  Contributed Photo

By Shana Bohac

Ehrlichiosis is a common tick-borne illness seen in animals and humans. It is most commonly seen in dogs and rarely in cats. This disease is caused by three different bacteria: Ehrlichia canis, Ehrlichia chaffeensis, and Ehrlichia ewingii. Outdoor dogs, particularly hunting dogs, with inadequate tick prevention are at higher risk; however, any dog that goes outside can be exposed to a tick and thus become infected. There are a wide variety of ticks that can spread the Ehrlichia bacteria through their saliva, however the brown dog tick and the lone star tick are the most common.

Ehrlichia canis is found worldwide with increased frequency in tropical and subtropical climates, making South Texas and the southern U.S. prime locations. This bacterium is spread primarily via the brown dog tick. The brown dog tick can tolerate hot and cold temperatures and can complete its entire lifecycle indoors. Dogs are their preferred hosts, however they will feed on a wide variety of mammals.

 Ehrlichia chaffeensis and Ehrlichia ewingii are found in the central, southeastern and eastern United States. The lone star tick is the primary transmitter of both of these bacteria. This tick is found in thick underbrush or high grass. They can bite painlessly and go unnoticed by its host for several days. The lone star tick requires three separate hosts to complete its life cycle and they will feed on a wide variety of mammals and birds.


The most common signs of a dog with Ehrlichiosis are decreased energy, loss of appetite, fever and weight loss. There may also experience an increase in bleeding, lameness and lymph node enlargement. Signs usually start one to three weeks after infection with the bacteria. Some dogs become chronically infected with the bacteria. These dogs may experience kidney failure, neurologic disturbances and chronic bleeding disorders.

Diagnosis is made based on clinical signs, history of exposure to a tick, and analysis of bloodwork. Initial bloodwork typically shows low platelets, anemia and low white blood cell counts. There are various blood tests that can be performed to confirm a diagnosis Ehrlichiosis. In-hospital tests may be available at some clinics. These tests are great screening tools for Ehrlichia; however, in early infections this test may not show up positive. Advanced testing may be needed if Ehrlichiosis is suspected.

Antibiotics are the treatment of choice for Ehrlichiosis. Twenty-eight days of treatment is recommended to clear the infection. In cases of severe anemia or blood loss, blood transfusions may be needed. Corticosteroids may also be used to help stop the body from destroying platelets and red blood cells.

Though this disease can be found in humans, there is very minimal risk, if any, of contracting these infections directly from a pet. The disease is only spread through the bite of a tick.

Prevention is so important in avoiding Ehrlichiosis. Good quality flea and tick products from your veterinarian can help prevent your pet from getting this potentially deadly disease. Flea and tick products from your veterinarian are much more effective and are much safer for your pet. Over-the-counter products have higher risk of toxicity and localized reactions.

Dr. Shana Bohac is a veterinarian at Lakeway Veterinary Clinic in Edna. She works on both small animals and equine patients. Submit questions to