Rickettsial diseases are a group of infectious disease caused by Rickettsia bacteria, although in some ways, they behave more like viruses than bacteria. Rickettsia are very small and need to invade cells in order to multiply. Most are passed on through the bites of external parasites such as ticks, fleas, lice, and mites. Below is a list of rickettsial diseases commonly seen in dogs.
Rocky mountain spotted fever is caused by Rickettsia rickettsii. Its name is misleading because most cases occur in forest regions of the American southeast, far from the Rocky Mountains. The disease occurs during the tick season, causing high fever, lethargy, loss of appetite, coughing, inflammation of the eyes, and general muscle and joint pain. There may be bleeding problems, such as nosebleeds or blood in the urine and stools. A reduction in platelets (thrombocytopenia) is often seen on a blood smear, and a rapidly increasing antibody count is usually diagnosed. An antibiotic from the tetracycline group given for 14 days is effective. Corticosteroids may also be used to counter inflammation. Minimize tick exposure and protect the dog with a specially developed anti-tick product.
Ehrlichiosis is a tick-borne disease that was first diagnosed among military dogs during the Vietnam War. It occurs mostly in southern United States and in Mediterranean Europe. The disease is caused by Ehrlichia canis and transmitted through bites from infected brown dog ticks (Rhipicephalus sanguineus). Affected dogs have enlarged lymph nodes and a fever for up to one week. They are often lethargic, appear stiff, and lose their appetite. There may be bleeding problems, such as nosebleeds or blood in the urine and stools. Some dogs develop stupor, lameness and lethargy. Untreated dogs appear to recover after 2 to 4 weeks. German Shepherd Dogs are thought to be more susceptible to the disease than other breeds. Blood counts early in the disease show reduced platelets (thrombocytopenia). In chronic illness, both red and white blood cell numbers also drop. A positive test for Ehrlichia canis antibodies confirms the diagnosis. Early treatment with an antibiotic from the tetracycline group (doxycycline) is very effective. When the disease has become chronic and bone marrow production is suppressed, antibiotic therapy must continue for several months; even then, the outlook is uncertain. To prevent ehrlichiosis, minimize tick exposure and protect the dog with tick control products.
Infectious cyclic thrombocytopenia is caused by Ehrlichia platys. It occurs from Texas to the Atlanta seaboard. There may be bleeding problems, such as nosebleeds or blood in the urine and stools. There are few signs of the disease. Affected dogs seldom need treatment; if necessary, tetracycline antibiotics are given.
Brown dog ticks (Rhipicephalus sanguineus
Salmon poisoning disease is caused by Neorickettsia helminthoeca and the Elokomin fluke fever agent that affect salmon in the waters of the Pacific Northwest of America, from San Francisco to Alaska. Five to seven days after eating infected raw fish, dogs vomit and rapidly develop explosive, watery to bloody diarrhea. They become weak and lethargic, and may have enlarged lymph nodes as well as eye and nose discharge. The clinical signs are similar to those of parvovirus. Diagnosis is confirmed by a history of eating raw fish and by identification of rickettsia or associated liver flukes in a sample of feces. Both pain control and re-hydration are essential elements of the treatment. In addition, an antibiotic drug from the tetracycline group is given. To prevent salmon disease, do not feed raw fish salmon to dogs. Freezing or smoking salmon will lower the risk.