*2.1.3.1. History*

Chronic cutaneous leishmaniasis (CCL) due to *L. killicki* was discovered for the first time on the basis of 30 strains isolated in 1980 when an outbreak of cutaneous leishmaniasis occurred in the microfocus of Tataouine in southeast Tunisia [32, 47]. The annual incidence of this disease was estimated to 10 cases per year [48].

The taxonomic status of *L. killicki* is not well defined yet. Indeed, it was initially characterized within the *L. tropica* complex [49]. By the revision of the *Leishmania* genus classification, *L. killicki* was considered as a separate phylogenetic complex [50]. In 2009, an update study by Pratlong et al. confirmed the inclusion of *L. killicki* within the *L. tropica* complex [51]. Phenetic and phylogenetic studies using multilocus microsatellite typing [52], PCR sequencing [53], and multilocus sequence typing (MLST) [54] also classified *L. killicki* within the *L. tropica* complex. A recent study on the evolutionary history of *L. killicki* relative to *L. tropica* suggested that *L. killicki* emerged from a single founder event and evolved independently from *L. tropica*. Thereby, they suggested naming this taxon *L. killicki* (synonymous *L. tropica*) [55, 56].

#### *2.1.3.2. Clinical forms*

Clinically, the lesion is frequently unique, ulcerous with a scab of 1–3 cm in diameter located on the face, with chronic evolution that can last for 4 years [57, 58] (**Figure 4**).

#### *2.1.3.3. Causative species*

The first description of CL due to *L. killicki* in 1980 was based on the isoenzymatic identification of about 30 strains from southeastern Tunisia. All of them were characterized as *L. killicki* zymodeme MON-8 [32]. Since this date and over a period of 36 years, only about 90 *L. killicki* strains were identified using the golden standard method [24, 30, 32, 51, 56]. The isoenzymatic analysis showed the presence of two zymodeme inside *L. killicki* taxon. Zymodeme MON-8 is the most frequent one. However, a new zymodeme MON-317 has been recently identified from two patients in Metlaoui, southwestern Tunisia [56].

**Figure 4.** Ulcerocrusted lesion of the neck caused by *L. killicki*. (Laboratory of Parasitology-Mycology, Faculty of Pharmacy, University of Monastir, Tunisia).

#### *2.1.3.4. Transmission cycle*

*2.1.2.5. Geographical distribution*

124 The Epidemiology and Ecology of Leishmaniasis

in Zaghouan province (**Figure 3**).

was estimated to 10 cases per year [48].

*2.1.3.1. History*

*2.1.3.2. Clinical forms*

*2.1.3.3. Causative species*

Geographical distribution of SCL is apparently restricted to the humid and sub-humid bioclimatic areas. Its distribution overlaps with that of VL in north and central Tunisia. Indeed, Haouas et al. reported that 95.3% of dermotropic *L. infantum* strains were isolated from the north of Tunisia, 2.83% from the centre (Kairouan and Sidi Bouzid) and 1.9% from the south (Sfax) [24]. The sporadic cases reported in the south of the country suggested an extension of SCL to the arid bioclimatic areas [24, 41]. Also, *L. infantum* MON-24 was unevenly distributed from the northern areas of the country: It was mainly isolated in Siliana, Manouba, Béja, Bizerte, and Jendouba provinces. The dermoviscerotropic zymodeme MON-1 was isolated in northern Tunisia, mainly in Siliana province, and the single CL *L. infantum* MON-80 strain was isolated

Chronic cutaneous leishmaniasis (CCL) due to *L. killicki* was discovered for the first time on the basis of 30 strains isolated in 1980 when an outbreak of cutaneous leishmaniasis occurred in the microfocus of Tataouine in southeast Tunisia [32, 47]. The annual incidence of this disease

The taxonomic status of *L. killicki* is not well defined yet. Indeed, it was initially characterized within the *L. tropica* complex [49]. By the revision of the *Leishmania* genus classification, *L. killicki* was considered as a separate phylogenetic complex [50]. In 2009, an update study by Pratlong et al. confirmed the inclusion of *L. killicki* within the *L. tropica* complex [51]. Phenetic and phylogenetic studies using multilocus microsatellite typing [52], PCR sequencing [53], and multilocus sequence typing (MLST) [54] also classified *L. killicki* within the *L. tropica* complex. A recent study on the evolutionary history of *L. killicki* relative to *L. tropica* suggested that *L. killicki* emerged from a single founder event and evolved independently from *L. tropica*.

Thereby, they suggested naming this taxon *L. killicki* (synonymous *L. tropica*) [55, 56].

on the face, with chronic evolution that can last for 4 years [57, 58] (**Figure 4**).

two patients in Metlaoui, southwestern Tunisia [56].

Clinically, the lesion is frequently unique, ulcerous with a scab of 1–3 cm in diameter located

The first description of CL due to *L. killicki* in 1980 was based on the isoenzymatic identification of about 30 strains from southeastern Tunisia. All of them were characterized as *L. killicki* zymodeme MON-8 [32]. Since this date and over a period of 36 years, only about 90 *L. killicki* strains were identified using the golden standard method [24, 30, 32, 51, 56]. The isoenzymatic analysis showed the presence of two zymodeme inside *L. killicki* taxon. Zymodeme MON-8 is the most frequent one. However, a new zymodeme MON-317 has been recently identified from

*2.1.3. Cutaneous leishmaniasis due to Leishmania killicki (synonymous L. tropica)*

Inthe last century,thetransmissioncycleof*L. killicki*inTunisiawas consideredasanthroponotic. However, in 2011, two epidemiological studies realized in the southwest and southeastern of Tunisia described the natural infection of *Ctenodactylus gundi* with *L. killicki* using molecular techniques suggestion a zoonotic transmission ofthis taxon [59, 60]. By the detection of *L. killicki* in its mid gut, *P. sergenti* was suspected to be the probable vector of this taxon [36, 61].

#### *2.1.3.5. Geographical distribution*

*L. killicki* was firstly described in the focus of Tataouine (southeast of Tunisia) [47]. For more than 20 years, no case was described outside this focus. Since 2004, some cases have been reported in Kairouan and Sidi Bouzid (centre of Tunisia), in Gafsa in the southwest and in Siliana in the north of the country [31, 62, 63]. A recent study focusing on the evolutionary history of this parasite using the microsatellite typing has supported the hypothesis of a zoonotic transmission cycle for *L. killicki* (syn. *L. tropica*) and suggested that Gafsa could be the historical focus of this parasite [56].

#### **2.2. Visceral leishmaniases**

Visceral leishmaniasis refers to the dissemination of the parasite *Leishmania* to the spleen, liver, lymphatic nodes, and bone morrow of the patient. A multitude of clinical features of the disease ensue gradually, the most important being splenomegaly, recurring and irregular fever, anemia, pancytopenia, weight loss, and weakness.
