Parasite Infection (Leishmaniasis) in Dogs

Leishmaniasis is a parasitic disease which is caused by leishmania parasite. Leishmania can affect dogs and humans alike. Leishmaniasis is caused by a protozoan parasite from the genus Leishmania and can only be transmitted by certain species of biting sand fly. The disease exists in two forms: cutaneous Leishmania and visceral Leishmania. Both types can affect dogs. Visceral Leishmania is much more serious than Cutaneous Leishmania, since it means that parasites have reached vital internal organs of the dog (black fever).

The infection occurs when flagellated parsites are injected in the host body through sandfly bite. Incubation period from infection to symptoms can range between one month to several years. On most occasion, the infection spreads throughout the body affecting different internal organs and the affected dog develops visceral or systemic disease. Up to 90% of dogs suffering from symptomatic Leishmaniasis have both visceral and cutaneous lesions. Kidneys, skin, spleen, liver, eyes and joints are the main organ systems that are affected by this condition. 

It is important to note that leishmaniasis is a zoonotic disease which can be transmitted to humans from dogs.

Since there are two types of leishmaniasis, cutaneous and viscerel, each type has different symptoms.

Visceral — affects organs of the abdominal cavity

Severe weight loss

Loss of appetite (anorexia)


Tarry feces (less common)


Nose bleed

Exercise intolerance

Cutaneous — affects the skin

Hyperkeratosis — most prominent finding; excessive epidermal scaling with thickening, depigmentation (loss of skin color), and chapping of the muzzle and footpads

Alopecia — dry, brittle hair coat with symmetrical hair loss

Nodules usually develop on the skin surface

Intradermal nodules and ulcers may be seen

Abnormally long or brittle nails are a specific finding in some patients 

Other signs and symptoms associated with leishmaniasis include:

Lymphadenopathy — disease of the lymph nodes with skin lesions in 90 percent of cases


Signs of renal failure — excessive urination, excessive thirst, vomiting possible

Neuralgia — painful disorder of the nerves

Pain in the joints

Inflammation of the muscles

Osteolytic lesions — a "punched-out" area with severe bone loss

Inflammation of the covering of bones; rare

Fever with an enlarged spleed (in about one-third of patients)

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