Leishmaniasis is a parasitic disease spread by the bite of the sandfly.
Causes, incidence, and risk factors
Leishmania are tiny protozoa. Their parasitic life cycle includes the sandfly and an appropriate host. Humans are one of those hosts. Leishmania infection can cause skin disease (called cutaneous leishmaniasis).
It can affect the mucous membranes with a wide range of appearances, most frequently ulcers. It may cause skin lesions that resemble those of other diseases including cutaneous tuberculosis, syphilis, leprosy, skin cancer (basal cell carcinoma), and fungus infections.
Leishmania can also cause systemic (throughout the body) disease (called visceral leishmaniasis) with fatal complications. When introduced into the body by the bite of a sandfly, the parasite migrates to the bone marrow, spleen, and lymph nodes.
Systemic infection in children usually begins suddenly with vomiting, diarrhea, fever, and cough. In adults, fever for 2 weeks to 2 months is accompanied by nonspecific symptoms, such as fatigue, weakness, and loss of appetite. Weakness increases as the disease progresses.
The skin may become grayish, dark, dry, and flaky. The parasites damage the immune system by decreasing the numbers of disease-fighting cells so death usually results from complications (such as other infections) rather than from the disease itself. Death often occurs within 2 years.
Cases of infection by Leishmania have been reported on all the continents except Australia. In the Americas, Leishmania can be found from Mexico south into the South American continent. Leishmaniasis has been reported among some military personnel returning from the Persian Gulf. (See Travelers guide to avoiding infectious diseases.)
- history of exposure to the bite of sandflies
- history of being in an area known for leishmaniasis
Systemic illness (visceral leishmaniasis):
- fever, persistent, long duration (weeks), may cycle irregularly
- night sweats
- appetite loss
- weight loss
- abdominal discomfort, vague
- vomiting (children)
- diarrhea (children)
- cough (children)
- scaly skin
- gray, dark, ashen skin
- thinning hair
Skin disease (cutaneous leishmaniasis):
Symptoms on the skin include:
- macule or papule, erythematous
- skin ulcer, forms at site of original lesion
- ulcer heals very slowly over a matter of months
- smaller lesions may form around the ulcer (satellite lesions)
Symptoms on mucous membranes include:
- nasal stuffiness
- runny nose
- ulcers and erosion of tissue (mouth, tongue, gums, lips, nose, nasal septum)
- swallowing difficulty (dysphagia) with esophageal involvement
- breathing difficulty, with tracheal involvement
Signs and tests
- enlarged spleen
- enlarged liver (less common than enlarged spleen)
- enlarged lymph nodes (less common than enlarged spleen)
- skin test, called the Montenegro skin test
- skin biopsy
- biopsy of the spleen
- bone marrow biopsy
- lymph node biopsy
- culture of biopsy material
- indirect immunofluorescent antibody test
- direct agglutination assay
Other tests (complementary to the diagnosis)
- CBC (shows decreased cellularity of blood, pancytopenia)
- hemoglobin (shows signs of anemia)
- serum protein (decreased)
- serum albumin (decreased)
- immunoglobulins (increased)
Antimony-containing compounds are the principal medications used to treat leishmaniasis. These include:
- meglumine antimonate
- sodium stibogluconate
Other drugs that may be used include:
- amphotericin B
Plastic surgery may be required to correct disfigurement by destructive facial lesions (mucocutaneous leishmaniasis). Removal of the spleen (splenectomy) may be required in drug-resistant cases (visceral leishmaniasis).
Cure rates are high with antimony compounds. Treatment should be accomplished before damage to the immune system occurs. Marked disfigurement may develop with mucocutaneous leishmaniasis.
- facial disfigurement
- fatal infections resulting from damage to the immune system
Calling your health care provider
Contact your health care provider if you have been in an area endemic for Leishmania and may have been bitten by sandflies, and now have symptoms suggestive of leishmaniasis.
Preventing sandfly bites is the most immediate form of protection. Insect repellent, appropriate clothing, screening of windows, and fine mesh netting around the bed (in endemic areas) will reduce exposure.
Public health measures to reduce the sandfly population and animal reservoirs are important. There are no preventive vaccines or drugs for leishmaniasis.
by Janet G. Derge, M.D.