Tick-borne diseases

Lyme disease

Lyme disease is caused by a tick-transmitted spirochete bacteria, and this organism commonly causes disease in humans and dogs. This disease has been reported in all 50 states. Clinical signs of infection include fever, loss of appetite (anorexia), lethargy, shifting leg lameness related to polyarthritis, and enlarged lymph nodes (lymphadenopathy). Cardiac and renal signs, which can lead to death, may also occur. Lyme disease can be difficult to accurately diagnose because some dogs get infected with the organism and develop detectable antibodies but do not develop signs of disease. The disease may be prevented by reducing exposure to tick habitats, protecting pets with tick control products, and vaccinating against Lyme disease.

Rocky Mountain Spotted Fever (RMSF)

RMSF occurs in many areas of the United States, but despite the name, it is most commonly seen east of the Mississippi River, especially in the southeastern U.S. The organism causes a wide variety of clinical signs including fever, anorexia, depression, vomiting, diarrhea, muscle pain, polyarthritis, neurological signs, epistaxis (nosebleeds), cutaneous hemorrhages, and death. There is no vaccine against RMSF so minimizing tick exposure by avoiding tick habitats and applying tick control products are recommended.

Canine ehrlichiosis

Canine ehrlichiosis is widespread in large parts of North and South America, Europe, Asia, and Africa. The disease occurs in acute, subclinical, and chronic phases. The acute phase starts with fever, anorexia, dyspnea (difficulty breathing), edema (tissue swelling), vomiting, lymphadenopathy (enlarged lymph nodes), and vasculitis (inflammation of blood vessels). The acute phase is transient, usually resolving in 1-2 weeks. Chronic signs of the disease include bleeding tendencies, anemia, severe weight loss and debilitation, and ocular and neurologic signs. There is no vaccine currently available, so tick control measures are important for disease prevention.

Canine anaplasmosis

Canine anaplasmosis is found in areas endemic for those tick species with high prevalence reported in California, Minnesota, Wisconsin, and many New England states, and occurs in dogs, horses, other animals, and humans. Clinical signs of disease include fever, lethargy, low lymphocyte count (lymphopenia), and low platelet count (thrombocytopenia). There is no vaccine against this disease, so tick control measures are again critical to disease prevention.

Canine babesiosis

Canine babesiosis is a disease transmitted by ticks. The disease organism infects and replicates in red blood cells causing immune-mediated reactions leading to hemolytic anemia and hemoglobinuria (blood pigments in urine). If not treated, the dog will develop icterus (yellowing of the skin), and enlargement of the spleen and lymph nodes. Severe anemia can develop, leading to diffuse intravascular coagulation, renal failure, and death. Tick control is important in disease prevention.

Canine hepatozoonosis

Canine hepatozoonosis is unique in that dogs must ingest the tick to become infected with this disease. Once ingested by the dog, the infective agents contained in the tick are released and infect white blood cells and cells of many other organs. Clinical signs of the disease include fever, anemia, and progressive weight loss. The disease can be seen in dogs of all ages but is most commonly seen in puppies. Because there is no vaccine, tick control is the best form of prevention.