Leishmaniasis

Veterinary advice should be sought before applying any treatment or vaccine.

Leishmaniasis

Leishmaniasis is a tropical/sub-tropical disease caused by Leishmania protozoa, which is spread by the bite of infected sandflies. L. braziliensis and L. siamensis are the two most common types seen in horses. There are several different forms of leishmaniasis in horses. Cutaneous leishmaniasis causes skin sores which are usually self-healing within a couple of months, but may leave behind ugly scars. These sores develop on the horse's muzzle, pinnae, scrotum, neck, legs, and periocular region. Visceral leishmaniasis causes systemic disease, where horses present with fever, weight loss and anemia, malaise, and swelling of the spleen, liver, and lymph nodes.

Leishmaniasis is on the list of diseases notifiable to the World Organization for Animal Health (OIE) and is classified as a Neglected Tropical Disease (NTD). There have been several isolated cases of leishmaniasis occurring in horses living in the United States (US). Endemic foci of leishmaniasis exist in Texas, Oklahoma, Ohio, and Florida. November 2012, a pregnant 10-year-old Morgan mare, was diagnosed with leishmaniasis by the University of Florida. The horse had no previous history of travel outside the eastern US. Symptoms presented as sores inside the mare's left ear.

Without treatment, most horses with the visceral form of the disease will die and those with diffuse cutaneous and mucocutaneous disease can suffer long infections associated with secondary life-threatening infections. Treatment should be considered even for self-healing cutaneous leishmaniasis, because of the disfiguring scars.

Symptoms

Skin sores
Fever
Diarrhea
Darkening of skin
Anemia
Weight loss
Malaise

Diagnosis

  • History
  • Clinical signs
  • Physical exam
  • Histopathology - superficial and deep granulomatous dermatitis.
  • PCR
  • Sequence analysis
  • Impression smear

Support

Therapies

Sodium stibogluconate: 6 ml/day administered via IV for 10 days, with treatment repeated once 30 days following the initial 10-day treatment

Prevention

Scientific Research

General Overviews

Risk Factors

  • Horses living in tropical or tropical regions
  • High populations of sandflies

Causative agent

Switch Animals