Canine Encephalitozoonosis 

Encephalitozoonosis is an infection caused by the protozoal parasite, Encephalitozoon cuniculi. Protozoa are one-cell organisms that infect various cells or tissues of the body and behave as tiny parasites. Infection with E. cuniculi generally affects some combination of the kidneys, brain, heart, and lungs.

Encephalitozoonosis is transmitted by ingestion of the parasite, through contact with contaminated urine, or passed through the placenta from the mother to her unborn pups. It affects dogs more than cats. The disease is most serious in young puppies. There is no breed or sex predilection.

The housing of multiple dogs in close quarters or in kennels is the most common environment associated with this infection. The disease is not very common in the United States.

What to Watch For

Stunted growth

Kidney failure

Neurologic abnormalities such as aggressiveness, convulsions, blindness or paralysis

Sudden death

Diagnosis of Encephalitozoonosis in Dogs

Certain findings are often consistent with the disease. Examples include nephritis (inflammation of the kidney), swollen kidneys, hepatomegaly (enlarged liver), small hemorrhages associated with all abdominal organs, and blood clots and cysts within the brain.

Initial diagnostic tests include a complete blood count, biochemical profile, and urinalysis. These tests may show one or more of the following abnormalities: anemia (low red blood cell count), elevated kidney and/or liver values, red and white blood cells in the urine.

A urine sediment examination with appropriate staining may reveal sporocysts (the reproductive element of protozoa) that have been shed from infected kidneys.

Dead puppies can be submitted for a necropsy (an animal autopsy). The organism can sometimes be found on microscopic examination of infected tissues.

Serologic tests on blood or cerebral spinal fluid are not commercially available for this infection at the present time.

Special immunologic procedures are performed in some research laboratories to identify this infectious agent.

Treatment of Encephalitozoonosis in Dogs

Treatment usually consists of supportive therapy, such as intravenous fluids and electrolytes. No specific treatment has been designed to date that successfully kills this protozoal organism. In advanced stages of the infection, it is generally felt that treatment is often a futile effort, and euthanasia should be considered.

Home Care and Prevention

Disinfecting the environment is important to help prevent reinfection. Sanitation is of the utmost importance. Eliminate the housing of multiple dogs in close quarters, and disinfect the premise on a regular basis.

Disinfecting the environment is also important in preventing infections in people. Transmission of E. cuniculi from infected dogs to people is possible and is of particular concern when exposed people have compromised immune systems. Transmission to people occurs from contact with infected urine or tissues.