The leishmania parasite causes a number of different diseases, varying from the lethal visceral leishmaniasis (kala azar) to mild, self-healing skin lesions. Clinical manifestations vary according to the different strains and the immunological status of the host. The parasite is transmitted by specific sandfly species. Several classifications of leishmaniasis are in use, based on different strains, mode of transmission, geography ('Old' and 'New World'), or clinical syndrome.
Although leishmaniasis occurs in 82 countries around the world, the majority of cases are limited to a few countries. Over 90% of visceral leishmaniasis cases in the world are reported from Bangladesh, Brazil, India and the Sudan; and more than 90% of cutaneous leishmaniasis cases are to be found in Afghanistan, Brazil, Iran, Saudi Arabia and Syria. Within these countries, the disease is usually limited to known endemic areas.
Visceral leishmaniasis usually responds well to pentavalent antimonial treatment (e.g. sodium stibogluconate). Hospitalization is recommended for visceral leishmaniasis - at least in the initial treatment phase - and a special treatment unit may need to be set up. The treatment lasts 15-30 days and is not without side-effects. The same drug can be used for cutaneous leishmaniasis if treatment is deemed necessary, e.g. in case of multiple lesions or infection acquired in geographic region where mucosal disease has been reported. Sometimes, infiltration inside the lesion itself may be useful.
Leishmaniasis and refugees
Migration movements from endemic areas appear to be an important factor in some outbreaks. Infected refugees may present symptoms that are unusual for the local health staff. This happened in Sudan from 1988 on, where people fleeing the south of the country, arrived in Khartoum, 900 kilometers from their homes, and were discovered to have kala azar. Also in Afghanistan, cases of cutaneous leishmaniasis were found among refugees in Jalalabad who originated from Kabul. Active cases originating from an endemic area are unlikely to transmit the disease in a refugee settlement unless the specific vectors are present.
The opposite situation, where refugees enter an endemic area, may result in an outbreak among non-immune people, with potentially high mortality in the case of visceral leishmaniasis.