Situation and trends
The leishmaniases are a group of diseases caused by the protozoa parasite Leishmania. Over 20 Leishmania species known to be infective to humans are transmitted by the bite of infected female phlebotomine sandflies. There are three main types of leishmaniasis: i) visceral, often known as kala-azar and the most serious form of the disease (VL); ii) cutaneous, the most common (CL); and iii) mucocutaneous.
The disease mainly affects poor people in Africa, Asia and Latin America, and is associated with malnutrition, population displacement, poor housing, weak immune system and lack of resources. Out of 200 countries and territories reporting to WHO, 97 countries and territories are endemic for leishmaniasis. This includes 65 countries that are endemic for both VL and CL, 10 countries that are endemic for VL only and 22 countries that are endemic for CL only. Four additional countries have previously reported cases of VL or CL.
Since 2013, the WHO Global Leishmaniasis programme has been reporting separately the number of new autochthonous cases, to monitor the trends in incidence, and the number of imported cases.
In 2015, 56 VL-endemic countries (75%) and 59 CL-endemic countries (68%) provided data for global surveillance. Ninety percent of global VL cases were reported from seven countries: Brazil, Ethiopia, India, Kenya, Somalia, South Sudan and Sudan. The 10 countries with the highest number of CL cases reported in 2015 are: Afghanistan, Algeria, Brazil, Colombia, Iran, Iraq, Peru, the Syrian Arab Republic, Tunisia and Yemen which together account for 87% of global reported CL incidence. In 2015, the number of imported cases of cutaneous leishmaniasis was particularly high in Turkey (815) and the Islamic Republic of Iran (908). Comparatively, the number of imported cases of visceral leishmaniasis was lower, with a total of 218 imported cases reported in 2015. The majority of these cases (76%) were reported in Ethiopia and Uganda.
As of September 2017, 38 VL-endemic countries (50%) and 42-CL endemic countries (48%) have reported 2016 data to the WHO Global Leishmaniasis programme.