Zoubir Harrat

The taxonomic status of Leishmania (L.) killicki, a parasite that causes chronic cutaneous leishmaniasis, is not well defined yet. Indeed, some researchers suggested that this taxon could be included in the L. tropica complex, whereas others considered it as a distinct phylogenetic complex. To try to solve this taxonomic issue we carried out a detailed study on the evolutionary history of L. killicki relative to L. tropica. Thirty-five L. killicki and 25 L. tropica strains isolated from humans and originating from several countries were characterized using the MultiLocus Enzyme Electrophoresis (MLEE) and the MultiLocus Sequence Typing (MLST) approaches. The results of the genetic and phylogenetic analyses strongly support the hypothesis that L. killicki belongs to the L. tropica complex. Our data suggest that L. killicki emerged from a single founder event and that it evolved independently from L. tropica. However, they do not validate the hypothesis that L. killicki is a distinct complex. Therefore, we suggest naming this taxon L. killicki (synonymous L. tropica) until further epidemiological and phylogenetic studies justify the L. killicki denomination. This study provides taxonomic and phylogenetic information on L. killicki and improves our knowledge on the evolutionary history of this taxon.

Thanks to the malaria eradication campaign launched in Algeria in 1968, the number of malaria cases fell down significantly from 95,424 cases in 1960 to 30 cases in 1978. At that time the northern part of the country was declared free of Plasmodium falciparum. Only few cases belonging to P. vivax persisted in residual foci in the middle part of the country. In the beginning of the eighties, the south of the country was marked by an increase of imported malaria cases. The resurgence of the disease in the oases coincided with the opening of the Trans-Saharan road and the booming trade with the neighbouring southern countries. Several authors insisted on the risk of introduction of malaria or its exotic potential vectors in Algeria via this new road. Now, the totality of malaria autochthonous cases in Algeria are located in the south of the country where 300 cases were declared during the period (1980-2007). The recent outbreak recorded in 2007 at the borders with Mall and the introduction of Anopheles gambiae into the Algerian territory show the vulnerability of this area to malaria which is probably emphasized by the local environmental changes. The authors assess the evolution of malaria in the Sahara region and draw up the distribution of the anopheles in this area.

Cutaneous leishmaniasis (CL) is endemic in Algeria where two forms have been previously described, the sporadic form caused by Leishmania infantum in the north and the cutaneous form caused by L. major in central and southern parts of the country. During 2005, a CL outbreak occurred in the province of Ghardaïa, located in the north of Sahara, where 2040 cases were recorded, of which several were from urban areas. Six strains isolated from patients with active lesions were identified by isoenzyme electrophoresis and by molecular typing using systematic sequencing of a large subunit of the RNA polymerase. Four of the strains belonged to a new zymodeme, MON-301, close to L. killicki MON-8. The two other isolates were identified as L. major zymodeme MON-25. The new dermatropic Leishmania close to L. killicki is reported for the first time in Algeria and coexists sympatrically with L. major MON-25 in the region of Ghardaïa where they occur in their usual vectors of Phlebotomus papatasi (L. major) and P. sergenti (L. tropica). This new parasite demonstrates the need for further investigations to elucidate the life cycle and transmission of the emergent disease and to evaluate its phylogenetic position in the taxonomy of Leishmania.

The authors report for the first time, in the south of Algeria, four imported cases of dracunculiasis in Malian Touaregs. The patients came from Mali. They remained two months in Tamanrasset before settling in Illizi where they have been working illegally for more than nine months. In August 2007, because of infected lesions appearing on their legs a month earlier, the patients decided to go to the Illizi hospital for treatment The diagnosis of dracunculiasis was made by direct observation of worms emerging from lesions and by microscopic examination of larvae. The patients were then isolated and treated. The Ministry of Health immediately took measures to avoid local transmission of the disease, never seen in the region. The measures consisted in increasing awareness campaign among medical and paramedical staff about dracunculiasis and in pointing out the importance of detection of new cases among nomadic populations. The risk of emergence of a new dracunculiasis indigenous focus in the south of Algeria should be seriously considered, especially as the number of immigrants from endemic countries is increasing considerably

The epidemiological situation of leishmaniasis in Tunisia is characterised by the co-existence in a very limited territory (165,000 km2, Sahara included), of 4 clinical forms: the infantile visceral leishmaniasis (VL) and 3 cutaneous leishmaniasis (CL) forms (sporadic, zoonotic and chronic). In addition to the useful epidemiological data, identification of the causative parasitic species is essential to determine the geographic distribution of each form and to select appropriate therapeutic procedure and suitable control measures. 226 Leishmania isolates, 135 human's coming from 59 VL cases and 76 CL cases and 91 canine's were identified by the isoenzyme electrophoresis reference technique. Results confirm the endemicity of the 4 forms mentioned above. The sporadic CL, confined to the North of the country is principally caused by L. infantum MON-24 (72.2%). VL which has reached the southern ridge in the central area of Tunisia, in the governorate of Kairouan (36 typed isolates), presents an unusual high proportion of L. infantum MON-24. In fact, this zymodeme, rather dermotropic is responsible for 47.2% of the cases vs 13% in the other regions of the country where L. infantum MON-1 remains predominant with 78.3% of typed isolates, the difference being statistically significant (P < 0.01). A third zymodeme, L. infantum MON-80 is sporadically pointed out during VL or in sporadic CL. Despite the high number of canine isolates (n=91) coming from 6 governorates, only the zymodeme L. infantum MON-1 was identified, letting hypothetic the reservoir of the 2 other zymodemes of the species identified in humans. Those absences may be related to cross infections, with a low sensitivity to L. infantum MON-24 leading to a selection of MON-1 at the time of culture passages. Hence it is important to develop molecular tools of direct identification on initial biological samples without going through cultures. Zoonotic CL remains the predominant cutaneous form in the central and southern area of Tunisia. However L. killicki, agent of the chronic CL, is confirming its presence out of its original focus of Tataouine in the southern-east of the country in both zoonotic CL and VL areas.

Iso-enzymatic characterization of 19 Leishmania strains isolated from Tunisian dogs revealed that all correspond to Leishmania infantum MON-1. This confirms the role of dog as a reservoir of the commonest zymodeme responsible for human visceral leishmaniasis in the Mediterranean basin. However, and in spite of the high number of identifications, many zymodemes, mainly the dermotropic ones as Leishmania infantum MON-24, frequently reported in humans, had never been isolated from dogs. The study of their cultural characteristics may contribute to explain the particular iso-enzymatic profile of dogs strains.

The isoenzymatic typing of 16 stocks of Leishmania, isolated from Tunisian visceral leishmaniasis (VL) cases, revealed that all strains belonged to Leishmania (L.) infantum species. Although zymodeme MON-1 was predictably the most frequent (9 cases), it came as a surprise that L. infantum MON-24 was responsible of about third of cases. This latter zymodeme, while previously reported in Tunisia, Algeria and Spain, was assumed to be a dermotropic and the few cases of VL that it caused occurred always in HIV infected patients. L. infantum MON-80, occasionally reported during both cutaneous and VL of immunocompetent infants was identified in 2 patients. This report confirms that in addition to the more common L. infantum MON-1, zymodeme MON-24 has a substantial role in generating VL in immunocompetent infants in Tunisia.

In Algeria, visceral leishmaniasis is caused principally by Leishmania infantum MON-1, a common agent of the disease on the edges of the mediterranean basin. Other zymodemes (MON-34 and MON-80) of the same complex have also been isolated from immunologically competent patients. In the present study, the authors report the presence of Leishmania infantum MON-24, the main agent of cutaneous leishmaniasis in northern Algeria, in five children with visceral leishmaniasis.

This study refers to 23 patients presenting with the sporadic forms of cutaneous leishmaniasis encountered in northern most humid parts of Tunisia. Culture inoculation for parasitic isolation was processed using two media: the classical NNN and a rabbit serum based medium (SLC). Cultures were positive in 17 cases with SLC medium and 13 cases with NNN medium. Eight isolates were typed using 15 isoenzymes systems. Six isolates were identified as Leishmania infantum MON-24 which confirms the crucial role of this zymodeme in causing this form of cutaneous leishmaniasis. The other two isolates were identified as Leishmania infantum MON-1, which is the principal agent of visceral leishmaniasis in the Mediterranean area.