Leishmaniasis is a complex disease comprised of multiple organisms in association. Each of these organisms responds differently to external factors. The environmental and socio-economic associations contribute to the dynamics and emergence of leishmaniasis across the globe. Ecological dynamics of the vector-parasite-host system of leishmaniasis influenced directly and indirectly both human and animal health. The transitions and rapid climate and socio-economic changes caused a transition of emergence and re-emergence of leishmaniasis outbreaks. The pattern of changes is influenced by the distribution and abundance as well as the spatial dynamics of vector and reservoirs species, which in turn disrupts ecosystem structure of vector and parasite. In Morocco, leishmaniasis are endemic and constitute a major public health threat. The observations showed significant variations in its spatial distribution and forms through Morocco with increase in the number of recorded cases during the last couple of years. Here, the authors discuss disease change related to climate and socio-economic influence.
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Environmental changes would directly affect the transmission patterns of vector-borne diseases (Patz et al., 2000) through their impacts at different spatial and temporal ecological scales (i.e. ecozones, biomes and ecotopes) (Ready 2008). Changes in climate are expected to affect the occurrence, the spatio-temporal distribution and the lifecycle of several vector borne diseases such as leishmaniases.
Leishmaniases are among the second most apparent resurging vector-borne disease after malaria; Leishmaniasis cause death to 20 000 to 40 000 deaths occur annually, and Malaria to 367 000 to 755 000 across the world (WHO 2015; Avar et al. 2012; WHO 2010). Leishmaniases occurs in 88 countries and four continents: Africa, North and South America, Asia and Europe with around 350 Million persons are at risk, 14 Million people infected worldwide and about 2 Million new cases recorded per year (WHO 2007, 2010). Thus, in some countries, leishmaniasis became an emergency health problem (e.g. India, Bangladesh, Sudan, Ethiopia, Brazil, Afghanistan, Algeria, Colombia, Iran, Syria, Costa Rica and Peru (Alvar et al., 2012). In Morocco, they present a serious public health problem. Three Leishmania species representing two leishmaniasis co-occur (Figure 1): Leishmania infantum (visceral leishaniasis), Leishmania major and Leishmania tropica (cutaneous leishmaniasis) were warned. In 2001-2010, the Ministry of Health reported about 38500, and 1300 cases of CL, and VL, respectively (MMH, 2011).
Figure 1. Components of the leishmaniasis transmission cycles reported in Morocco. The diagram show the association of several organisms in the dynamics of three different leishmaniasis forms occurred across the country
Depending on the origin of the infection, leishmaniasis in Morocco can be grouped into three forms: 1) Zoonotic Visceral Leishmaniasis (ZVL) caused by L. infantum and maintained in long term by dogs and bites of three vector species; P. ariasi, P. perniciosus, and possibly P. longicuspis, 2) Zoonotic Cutaneous Leishmaniasis (ZCL) caused by L. major, where the parasite is maintained among small mammals and human by the bites of P. papatasi, and 3) Anthroponotic Cutaneous Leishmaniasis (ACL) caused by L. tropica, human is the main host-reservoir in Morocco (Kahime et al., 2014, Kahime et al., 2015a), while zoonotic foci have been reported from Israel, Kenya and Egypt (Sang et al., 1992; Shehata et al., 2009). It transmitted among human hosts by the bites of P. sergenti (e.g.; Nejjar et al., 1998; Rioux et al., 1982; Rhajaoui, 2009; Pratlong et al., 1991; Kahime et al., 2015b).