
	PETS, ANIMALS, BIOLOGY TOPICS

Rickettsial Diseases

These newly identified diseases are due to a group of bacteria called rickettsiae. These germs behave, in some ways, more like viruses than bacteria. They are as small as virus particles 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.

Rocky Mountain Spotted Fever

This disease is misleadingly named: in fact, most cases occur in forest regions of the American southeast, far from the Rocky Mountains. It is caused by Rickettsia rickettsii and occurs during the tick season. The bacteria causes a 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.

Diagnosis & Treatment of Rocky Mountain Spotted Fever

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. A positive response is seen within a few days. Corticosteroids may also be used to counter inflammation.

Prevention of Rocky Mountain Spotted Fever

Minimize tick exposure and protect the dog with a specially developed anti-tick product.

Ehrlichiosis

This tick-borne disease was first diagnosed in the United States 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 in bites from infected brown dog ticks (Rhipicephalus sanguineus)

Affected dogs have enlarged lymph nodes and a fever for up to a 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 vague neurological signs, such as stupor, lameness and vagueness. Untreated dogs appear to recover after 2 to 4 weeks. Certain breeds are thought to be more susceptible to the disease (German Shepherd dog) than others.

Diagnosis & Treatment of Ehrlichiosis

Blood counts early in the disease show reduced platelets (thrombocytopenia). In chronic illness, both red and white blood cell numbers also drop (pancytopenia). Ehrlichia canis may be identified in blood cells. A positive test of Ehrlichia canis antibodies confirms the diagnosis.

Early treatment with an antibiotic from the tetracycline group (such as 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.

Prevention of Ehrlichiosis

Minimize tick exposure and protect the dog with a specially developed anti-tick product.

Infectious Cyclic Thrombocytopenia

This disease is caused by Ehrlichia platys and was first detected in Florida in 1970s. It occurs from Texas to the Atlanta seaboard. There may be bleeding problems, such as nosebleeds or blood in the urine and stools.

Diagnosis & Treatment of Infectious Cyclic Thrombocytopenia

A cyclical drop in blood platelets occurs but there are few signs of the disease. Platelet numbers drop, and then rapidly return to normal. Affected dogs seldom need treatment, but if necessary tetracycline antibiotics are given.

Salmon Disease

This disease is caused by rickettsiae bacteria 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 discharges.

Diagnosis & Treatment of Salmon Disease

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 treatment. In addition, an antibiotic drug from the tetracycline group (such as doxycycline) is given to combat the infection.