Cutaneous leishmaniasis, the most common form of leishmaniasis, causes long-term skin lesions on exposed areas of the skin. It is caused by a protozoan parasite belonging to the genus Leishmania and is transmitted via infected phlebotomine sand flies. In North Africa, particularly Algeria, the disease represents a major public health problem. This retrospective study, which focuses on the agropastoral region of Djelfa (central Algeria) during a period of 16 years, from 2006 to 2021, is part of the surveillance of cutaneous leishmaniasis to identify the key factors favouring its probable spread. The analyzed data reveal that this disease is more prevalent in male patients (53.60%) and is highly widespread in this vast area of 66,415 km² with a total of 3864 CL cases, reaching a peak of 1407 cases in 2006. Statistically, the Pearson correlation validated by the p-value shows, in an original and sometimes unexpected way, that certain factors, such as temperature linked to climate change, are playing a significant role in the probable spread of the disease in Djelfa and its surrounding regions. The concentration of the population in some specific rural areas with limited or nonexistent access to public health services is another potential factor in disease transmission. The results were highlighted by a significant correlation coefficient ($r=0.66$) with a p-value less than 0.01. While there is currently no vaccine or prophylactic drug available, our research represents a preliminary approach that addresses various epidemiological aspects of the disease. This paves the way for a proactive preventive strategy involving the control of vector-borne diseases.

Background: The wide distribution of phlebotomine vectors complicates the leishmaniasis situation in the world, with the risk of spreading from rural to urban areas. Our study investigates for the first time the ecology and distribution of sand fly populations in leishmaniasis focus (Djelfa, Algeria). Methods: Sampling is performed using light traps from August 2021 to July 2022 at ten sites with different biotopes: two peri-urban stations (Ain Oussera and Hassi Bahbah), one urban station (Djelfa), and three rural stations (Ain El-Bel, Haniet Ouled Salem and Mlaga). Results: A total of 2,866 specimens with 12 species belonging to Phlebotomus and Sergentomyia were identified with the first record of Phlebotomus langeroni female nationally, revealing a good diversity of up to 1.812 bits. The greatest richness of species was found in rural sites at Ain El Bel station, while the lowest richness was observed in the first peri-urban site of Ain Oussera station. Interestingly, the surveyed species were evenly distributed across all the study sites, in particular Phlebotomus papatasi with 57.29%. Statistical treatment revealed a strong positive relationship between temperature and species (p< 0.001, r= 0.91). Considering the other factors, there was a moderate link between species richness and altitude (p= 0.01 R2= 0.519). However, neither rainfall nor wind speed (p> 0.05) were correlated with sand fly fauna. Moreover, humidity showed a negative correlation (p< 0.001, r= -0.96). Conclusion: The findings of this study on phlebotomine fauna in this endemic region for leishmaniasis provide valua­ble data to support the success of a vector control program.