*2.1.1.4. Transmission cycle*

*L. major* has a zoonotic transmission cycle. The fat sand rat *Psammomys obesus* and the gerbils *Meriones shawi* and *Meriones libycus* are reservoir hosts [32, 33]. Recently, a natural infection with *L. major* zymodeme MON-25 has been reported in a specimen of least weasel (*Mustela nivalis*) suggesting its potential role as reservoir host of ZCL [34].

In 1987, Ben Ismail et al. [33] proved that *Phlebotomus* (*P.*) *papatasi* is the vector of *L. major* in Tunisia. Indeed, the isoenzymatic identification of isolated promastigotes from infected females of *P. papatasi* revealed the zymodeme MON-25 already identified in human CL cases (**Figure 2**). In Tunisia, This sand fly species is essentially spread in semi-arid, arid, and Saharan bioclimatic stages [35, 36].

**Figure 2.** Transmission cycles of the dermotropic *Leishmania* zymodemes in Tunisia. (Laboratory of Parasitology-Mycology, Faculty of Pharmacy, University of Monastir, Tunisia).

#### *2.1.1.5. Geographical distribution*

Zoonotic CL due to *L. major* is the main noso-geographic form widespread in whole central and southern part of Tunisia. In 2002, 15 of 23 Tunisian provinces were considered as endemic for ZCL with two to three thousand cases annually [37]. Since 2012, *L. major* has been reported in 19 provinces. Out of them, seven were in the north of the country. Key factors leading to the spread of this disease are presently unknown. Dynamics of rodent populations, vector dispersal, and climate change may be involved in the spatiotemporal dynamics of the disease [24] (**Figure 3**).

**Figure 3.** Geographical distribution of dermotropic *Leishmania* taxa [24].

#### *2.1.2. Cutaneous leishmaniasis due to Leishmania infantum*

#### *2.1.2.1. History*

*L. infantum* is primary known as a viscerotropic species responsible for the genesis of visceral leishmaniasis. Nevertheless, the first case of CL due to this species in Tunisia was described in 1916 in Sakiet Sidi Yousef, El Kef (north of Tunisia) by Nicolle and Blanc (1918) [20]. This disease has been sporadically reported with an annual incidence of approximately 20 or 30 cases per year [38]. The geographical distribution of this sporadic form overlaps with that of VL.

#### *2.1.2.2. Clinical forms*

*2.1.1.5. Geographical distribution*

122 The Epidemiology and Ecology of Leishmaniasis

**Figure 3.** Geographical distribution of dermotropic *Leishmania* taxa [24].

*2.1.2. Cutaneous leishmaniasis due to Leishmania infantum*

*L. infantum* is primary known as a viscerotropic species responsible for the genesis of visceral leishmaniasis. Nevertheless, the first case of CL due to this species in Tunisia was described in

[24] (**Figure 3**).

*2.1.2.1. History*

Zoonotic CL due to *L. major* is the main noso-geographic form widespread in whole central and southern part of Tunisia. In 2002, 15 of 23 Tunisian provinces were considered as endemic for ZCL with two to three thousand cases annually [37]. Since 2012, *L. major* has been reported in 19 provinces. Out of them, seven were in the north of the country. Key factors leading to the spread of this disease are presently unknown. Dynamics of rodent populations, vector dispersal, and climate change may be involved in the spatiotemporal dynamics of the disease

Unfortunately, the low prevalence of sporadic CL (SCL) as well as the absence of published data concerning the clinical polymorphism of this noso-geographical form of CL prevents us to make a define description of the lesion. Previous studies reported that in over 80% of cases, CL caused by *L. infantum* is characterized by a single small lesion on the face. The ulcerocrusted form is the most common [38, 39]. Nevertheless, lupoid with a striking infiltrated patch, erythematous and squamous forms were also reported.
