Leishmaniasis Worldwide and Global Estimates of Its Incidence

Abstract

As part of a World Health Organization-led effort to update the empirical evidence base for the leishmaniases, national experts provided leishmaniasis case data for the last 5 years and information regarding treatment and control in their respective countries and a comprehensive literature review was conducted covering publications on leishmaniasis in 98 countries and three territories (see ‘Leishmaniasis Country Profiles Text S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28, S29, S30, S31, S32, S33, S34, S35, S36, S37, S38, S39, S40, S41, S42, S43, S44, S45, S46, S47, S48, S49, S50, S51, S52, S53, S54, S55, S56, S57, S58, S59, S60, S61, S62, S63, S64, S65, S66, S67, S68, S69, S70, S71, S72, S73, S74, S75, S76, S77, S78, S79, S80, S81, S82, S83, S84, S85, S86, S87, S88, S89, S90, S91, S92, S93, S94, S95, S96, S97, S98, S99, S100, S101’). Additional information was collated during meetings conducted at WHO regional level between 2007 and 2011. Two questionnaires regarding epidemiology and drug access were completed by experts and national program managers. Visceral and cutaneous leishmaniasis incidence ranges were estimated by country and epidemiological region based on reported incidence, underreporting rates if available, and the judgment of national and international experts. Based on these estimates, approximately 0.2 to 0.4 cases and 0.7 to 1.2 million VL and CL cases, respectively, occur each year. More than 90% of global VL cases occur in six countries: India, Bangladesh, Sudan, South Sudan, Ethiopia and Brazil. Cutaneous leishmaniasis is more widely distributed, with about one-third of cases occurring in each of three epidemiological regions, the Americas, the Mediterranean basin, and western Asia from the Middle East to Central Asia. The ten countries with the highest estimated case counts, Afghanistan, Algeria, Colombia, Brazil, Iran, Syria, Ethiopia, North Sudan, Costa Rica and Peru, together account for 70 to 75% of global estimated CL incidence. Mortality data were extremely sparse and generally represent hospital-based deaths only. Using an overall case-fatality rate of 10%, we reach a tentative estimate of 20,000 to 40,000 leishmaniasis deaths per year. Although the information is very poor in a number of countries, this is the first in-depth exercise to better estimate the real impact of leishmaniasis. These data should help to define control strategies and reinforce leishmaniasis advocacy.

Genetic divergence in populations of Lutzomyia ayacuchensis, a vector of Andean-type cutaneous leishmaniasis, in Ecuador and Peru

“…These are in two currently defined genera, Phlebotomus in the Old World and the genus Lutzomyia in the New World (Munstermann, 2004;Bates, 2007;Kato et al, 2010;Alvar et al, 2012). Only a restricted number of species support the development of specific Leishmania species and consequently transmit the parasites (Kato et al, 2010;Ready, 2013).…”

First human cases of Leishmania (Viannia) naiffi infection in Ecuador and identification of its suspected vector species

“…The disease is widely distributed around the world especially in tropical and subtropical areas, affecting at least 12 million people in 98 countries (Alvar et al, 2012).…”

“…Approximately 20 Leishmania species are known to be pathogenic to humans, and species infecting is the major determinant of clinical outcome (cutaneous, mucocutaneous and visceral forms) (Alvar et al, 2012). Leishmania protozoa are transmitted by the female phlebotomine sand fly (Killick-Kendrick, 1999;Munstermann, 2004;Bates, 2007).…”

Resveratrol: A miraculous natural compound for diseases treatment

“…Over 350 million people are at risk, and approximately 0.9–1.2 million new cases of leishmaniasis occurs per year (Alvar et al., 2012). During blood feeding by female sandflies, metacyclic promastigotes are regurgitated.…”