Leishmania Infection in Dogs

Overview of Leishmania Infection in Dogs

Leishmaniasis is an parasitic infectious disease of dogs and people that is usually limited to tropical regions of the world, including South America, the Mediterranean, Middle East and Asia. The subspecies of the parasite Leishmania donovani can infect dogs, causing a disease form called visceral leishmaniasis. Dogs serve as a reservoir of infection. The disease is transmitted among dogs and to people by sandflies.

The disease was not thought to be naturally present in the United States. However, there have been cases in the United States in dogs that have traveled to areas where natural infection occurs. Sand fly species, presumably capable of transmitting the disease, are present in the United States creating the potential for the disease to increase in incidence. General interest in this disease has risen because of a recent outbreak of leishmaniasis diagnosed in several foxhounds in a kennel in New York. The kennel and kennel veterinarians are working with the Centers for Disease Control and Prevention (CDC) to identify the source and extent of infection in the dog population.

Dogs may become infected when bitten by an infected sand fly, and the parasite infects cells in many organs including bone marrow, liver, kidney, spleen, lymph nodes and skin. After an incubation period of 6 to 18 months, the dog may become ill with a variety of clinical signs.

What to Watch For

• Weight loss
• Hair loss
• Skin ulcerations
• Abnormal toenail growth
• Bleeding from the nose
• Kidney failure
• Liver failure
• Lameness

Because these clinical signs are variable and not specific, making a diagnosis is difficult unless the veterinarian considers the disease as a possibility.

Diagnosis of Canine Leishmania

Diagnosis is completed by examining samples of bone marrow or lymph node to look for the parasite, or by testing serum. Many times examination of bone marrow or lymph node is negative even when the dog is infected. As a result, serum tests are often preferred for diagnostic screening. There are two tests available for identifying antibodies to the parasite in serum:

• Immunofluorescent antibody test (IFA) offered on a request-only basis by the CDC
• Enzyme linked immunosorbent assay (ELISA) regularly offered by Heska Corporation

Both tests require a submission and request by a licensed veterinarian.

Treatment Leishmania Infection in Dogs

Treatment is difficult and there are currently no drugs available now that cure the disease. Some drugs may be used in an attempt to lessen the signs of illness and require administration for a long time. Relapse of disease may occur weeks, months or years later.