Sand Fly

Leishmaniasis is a disease caused by a protozoan parasite found in dogs and certain rodents in many parts of the world, most commonly in rural areas.

The parasite is transmitted by a small biting sand fly (Phlebotomus spp.). It is an important disease because humans can also contract Leishmaniasis. There is no direct transmission from dog to man, or vice versa. You cannot become infected with Leishmaniasis from your dog or cat.

Leishmaniasis can cause one or both of two types of infections, a cutaneous or skin infection and a visceral or organ infection.

Leishmaniasis is common in the Mediterranean, South and Central America, and southern Mexico.

What are the clinical signs of Leishmaniasis?

Virtually all dogs will develop the visceral form of the disease. Ninety percent will also have cutaneous involvement. The clinical signs associated with the visceral form include fever, anorexia, weakness, exercise intolerance, severe weight loss,  diarrhea, vomiting, bleeding from the nose, and blood in the stool (usually seen as dark, tarry stools, called melena). Most dogs will develop swollen lymph nodes and an enlarged spleen, and will progress to kidney failure.

Clinical signs of the cutaneous form most commonly include thickening and hardening of the tissues on the muzzle and footpads, called hyperkeratosis. Many dogs will lose the pigment or dark coloring of these tissues as the disease progresses. Nodules or hard lumps may form in the skin and the coat often appears dull and brittle with areas of hair loss.

How is the disease diagnosed?

Leishmaniasis is diagnosed on medical history, especially recent travel to an area with endemic Leishmaniasis, and clinical signs. Blood and urine tests are usually performed along with tissue biopsies.

What is the prognosis?

“The prognosis for a pet diagnosed with Leishmaniasis is very guarded to grave.”

The prognosis for a pet diagnosed with Leishmaniasis is very guarded to grave. Most dogs die from kidney failure. Severely ill pets may not be able to undergo treatment. Your veterinarian will provide you with specific treatment recommendations based on your pet’s condition.