Introduction
Leishmania tropica (Kinetoplastida: Trypanosomatidae) is the major cause of Anthroponotic Cutaneous Leishmaniasis (ACL) in the Middle East and some areas of North Africa (Pratlong et al., 2009) andPhlebotomus sergenti Parrot, 1917 (Diptera: Psychodidae) is its main vector (Guilvard et al., 1991; Schnur et al., 2004). For a long time, P. sergenti was considered the sole vector ofL. tropica (Al-Zahrani et al., 1988; Guilvard et al., 1991) however, the vectorial capacity of P. arabicus has been demonstrated in a focus in northern Israel (Svobodová et al., 2006), and P. similis is considered a probable vector on the island of Crete (Ntais et al., 2014). In Morocco, P. sergenti exhibits a wide ecological plasticity although it is believed to have a marked preference for semi-arid habitats (Boussaa et al., 2009), therefore, increased vector surveillance is essential to prevent and control CL outbreaks. In emerging ACL Moroccan foci, P. sergenti density varies from 4 to 16 specimens/m2(Ramaoui et al., 2008) with 12.8% to 76.7% of relative abundance (Boussaa et al., 2009).
The World Health Organization included Morocco as one of the 12 high-burden countries for CL (WHO, 2016). There are three endemicLeishmania species in Morocco: L. major, L. tropica, (both dermotropic) and L. infantum (mainly viscerotropic). Leishmania tropica has the widest geographic distribution (Ministry of Health, Morocco, 2016; Mouttaki et al., 2014) and until 1989, ACL had been mainly reported in hypoendemic rural foci scattered around the sub-arid area of central Morocco. Later, ACL emerged in several northern, central and southern provinces of the country, initially as new outbreaks and then establishing endemic foci that highlighted the expansion of this Leishmania species (Ajaoud et al.,2013). The first CL case in Settat province (central Morocco) was detected in El Borouj locality in 2006, preceding an epidemic outbreak and then establishing as an endemic area (Amarir et al., 2015; Gijón-Robles et al., 2018). Currently, El Borouj is the only active CL focus in the province of Settat (Ministry of Health, Morocco, 2016).
The identification of factors that determine the ACL emergence and expansion is required to develop better interventions for this largely neglected disease. We showed that differences in the exposure to theL. tropica vector, reflected by differences in P. sergentidensity in the households, was the only factor associated with CL cases in El Borouj focus (Gijón-Robles et al. in 2018).
On the other hand, the presence of four mitochondrial (mt) lineages within P. sergenti has been previously reported (Yahia et al. 2004; Barón et al. 2008; Merino-Espinosa et al., 2016) and three of them are present in Morocco. Phenotypic differences of biomedical importance may exist between these mitochondrial lineages, thus population genetics could help to assess the threat of the geographical expansion of ACL. Therefore, our aim was to analyse the density and genetic characteristics of P. sergenti populations in two Moroccan localities, one endemic and another free of ACL.
Material and methods