Leishmaniasis

Alternative names   

Kala-azar  Espundia

Definition   

Leishmaniasis is a parasitic disease  occuring in tropical and temperate countries spread by the bite of the sandfly of the genera: Phelbotomus ( old world) and Lutzomyia ( New world) It occurs in three forms: (1) visceral disease, characterized by fever, weight loss, anemia, and enlargement of the liver and spleen developing over months to years; (2) cutaneous disease, manifested by skin ulcers on exposed parts of the body developing over weeks to months; and (3) mucocutaneous disease, characterized by disfiguring erosions of the mucous membranes of the nose, mouth, and throat. Sandflies typically bite from dusk to dawn, but may bite during the daytime if disturbed. 

Leishmania are tiny protozoa.

It’s life cycle includes a bite from sandfly and an appropriate host. Humans are one of those hosts. Leishmania infection can cause skin disease (called cutaneous leishmaniasis).

Clinical presentations:

Visceral leishmaniasis (VL), also known as kala azar, is the most severe form of the disease, which, if untreated, has a mortality rate of almost 100%. It is characterized by irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and anaemia.

Mucocutaneous leishmaniasis (MCL), or espundia, produces lesions which can lead to extensive and disfiguring destruction of mucous membranes of the nose, mouth and throat cavities.

Cutaneous leishmaniasis (CL) can produce large numbers of skin ulcers—as many as 200 in some cases—on the exposed parts of the body, such as the face, arms and legs, causing serious disability and leaving the patient permanently scarred. Diffuse cutaneous leishmaniasis (DCL) never heals spontaneously and tends to relapse after treatment. The cutaneous forms of leishmaniasis are the most common and represent 50-75% of all new cases.

Distribution:

Distribution Map

• The leishmaniases are now endemic in 88 countries on five continents—Africa, Asia, Europe, North America and South America—with a total of 350 million people at risk.

• It is believed that worldwide 12 million people are affected by leishmaniasis;
• Of the 500 000 new cases of Visceral L which occur annually, 90% are in five countries: Bangladesh, Brazil, India, Nepal and Sudan.

• 90% of all cases of Mucocutaneous L. occur in Bolivia, Brazil and Peru.

• 90% of all cases of Cutaneous L occur in Afghanistan, Brazil, Iran, Peru, Saudi Arabia and Syria, with 1-1.5 million new cases reported annually worldwide.

Leishmania/HIV Co-infection

Visceral / HIV Co-infection distribution

Leishmania/HIV co-infection is emerging as an extremely serious, new disease and it is increasingly frequent.

Symptoms  of the varrious forms of L.

• history of exposure to the bite of sandflies
• history in being in an area known for leishmaniasis

Systemic illness (visceral leishmaniasis)

• fever, persistent, long duration (weeks), may cycle irregularly
• night sweats
• fatigue
• weakness
• appetite loss (anorexia)
• weight loss
• abdominal discomfort, vague
• vomiting (children)
• diarrhea (children)
• cough (children)
• skin, scaly
• skin, gray, dark, ashen
• hair, thinning

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  mucocutaneous L.include:

• nasal stuffiness
• runny nose (coryza)
• nosebleed (epistaxis)
• ulcers and erosion of tissue (mouth, tongue, gums, lips, nose, nasal septum)
• swallowing difficulty (dysphagia) with esophageal involvement
• breathing difficulty, with tracheal involvement

Diagnostic Signs and tests   

SIGNS ( in addition to the above)

• enlarged spleen
• enlarged liver (less common than enlarged spleen)
• enlarged lymph nodes (less common than enlarged spleen)

Diagnostic TESTS

 

• skin test, 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

Treatment   

Antimony-containing compounds are the principal medications used to treat leishmaniasis. These include:

• meglumine antimonate: 20mg /kg/day in 2divided doses IM or IV  x 28 days
• sodium stibogluconate 20mg /kg/day in 2divided doses IM or IV  x 28 days

Other drugs that may be used include:

• pentamidine : For Cutaneous L. 2mg/kg x 7 doses
• amphotericin B  1mg/kg/day  x 20 days

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).

Prognosis   

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.

Complications   

• facial disfigurement
• fatal infections resulting from damage to the immune system
• hemorrhage

Prevention   

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. The netting must be finer-mesh (at least 18 holes to the linear inch) since sand flies are smaller than mosquitoes.

Public health measures to reduce the sandfly population and animal reservoirs are important. There are no preventive vaccines or drugs for leishmaniasis.

Dr Paul Assad

References

Manson texbook

Sanford Guide : guide to antimicrobial therapy

Travel Medicine advisor

Travel medicine and Health ( Duponr Steffen)

CDC webpage