Mediterranean countries, Asia, Africa, Middle and South America
Mucocutaneous leishmaniasis
South and Middle America
90% of all cases in four countries; Bolivia, Brazil, Peru and Ethiopia
Visceral leishmaniasis (kala-azar)
Mediterranean countries (endemic to the east coast of Spain), Asia, Africa, South and Middle America
Transmission
The disease is transmitted to humans by sandflies which live near to human dwellings and suck blood at night.
The infection sources are, depending on the type of leishmania, dogs, rodents, humans or other animals.
Significance worldwide
Exists on four continents. Endemic in 98 countries, most of which are developing countries.
Viscleral leishmaniasis: annually about 50-90 000 new cases, > 20 000 deaths, epidemics
Cutaneous leishmaniasis: 700 000-1 000 000 new cases per year
In other regions, the disease may be encountered in visitors to and immigrants from endemic areas.
Signs and symptoms
Not all infections are symptomatic.
In cutaneous leishmaniasis, an itching papule will appear on the skin at the site of the sandfly bite after an incubation period of several weeks or months. The papule will develop into a round crater-like ulcer with elevated borders and with granulation and discharge at the bottom. The ulcer will heal within a few years but leaves a scar.
Mucocutaneous leishmaniasis starts with a facial lesion that will heal. Mucosal ulcers will develop after several months or years. These ulcers may totally destroy the nasal septum and the soft structures of the mouth and nose.
The incubation period of visceral leishmaniasis is usually 3-8 months, but may vary from 3 weeks to 2 years. Typical symptoms include fever and weight loss. Other possible symptoms include diarrhoea, dark pigmented skin lesions, and bleeding symptoms. The most common findings on physical examination are lymphadenopathy and hepatosplenomegaly, as well as pancytopenia and hypergammaglobulinaemia.
Visceral leishmaniasis may appear even decades after the primary infection, if an immunodeficiency develops. The symptoms may be severe or atypical. Visceral leishmaniasis is an important opportunistic infection related to HIV infection.
Diagnosis
For cutaneous and mucocutaneous leishmaniasis, a biopsy or tissue scrapings should be taken from the edge of a lesion.
For visceral leishmaniasis, a bone marrow biopsy is usually collected.
The collected tissue samples should be sent for staining and PCR assays.
PCR is more sensitive than staining and identifies also the leishmanial species, which has an impact on selecting the treatment for cutaneous leishmaniasis.
In visceral leishmaniasis, serum antibodies can usually also be detected.
Treatment may be centralised in specialised hospitals.
Cutaneous leishmaniasis is treated with minor surgery or with pharmacotherapy (depending on leishmania species with pentavalent antimony, liposomal amphotericin B, pentamidine or imidazole derivatives). Cutaneous leishmaniasis acquired from the American continent is generally to be treated with systemic medication due to the risk of developing mucocutaneous leishmaniasis.
The treatment of mucocutaneous leishmaniasis is in practice the same as that of visceral leishmaniasis.
Response to medical treatment is good, but mucocutaneous leishmaniasis is the most difficult form to treat.
Prevention on individual level
Neither vaccine nor prophylactic medication is available.
Protection against sandflies: avoidance of staying outdoors during dark hours, covering clothing, insect repellent on bare skin, insecticide treated bed net. Due to its small size, the sandfly is able to penetrate an untreated net.
References
Copeland NK, Aronson NE. Leishmaniasis: treatment updates and clinical practice guidelines review. Curr Opin Infect Dis 2015;28(5):426-37. [PubMed]
Showler AJ, Boggild AK. Cutaneous leishmaniasis in travellers: a focus on epidemiology and treatment in 2015. Curr Infect Dis Rep 2015;17(7):489. [PubMed]
Blum J, Buffet P, Visser L et al. LeishMan recommendations for treatment of cutaneous and mucosal leishmaniasis in travelers, 2014. J Travel Med 2014;21(2):116-29. [PubMed]
Mansueto P, Seidita A, Vitale G et al. Leishmaniasis in travelers: a literature review. Travel Med Infect Dis 2014;12(6 Pt A):563-81. [PubMed]
Murray HW. Leishmaniasis in the United States: treatment in 2012. Am J Trop Med Hyg 2012;86(3):434-40. [PubMed]