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.

Since its first detection in 2010, Aedes albopictus has spread across northern Algeria, where vector control relies on the use of chemical insecticides. This study aimed to evaluate the susceptibility of Ae. albopictus populations from Algiers to commonly used larvicides and adulticides, as well as to characterize the underlying resistance mechanisms. Eggs were collected from three sites in Algiers. The susceptibility of larvae to temephos and Bacillus thuringiensis israelensis (Bti), as well as that of adults to permethrin, deltamethrin, malathion, and bendiocarb was evaluated using WHO bioassays. Genotyping of knockdown resistance (kdr) mutations was performed via PCR and sequencing. Metabolic resistance mechanisms were investigated using CDC bottle bioassays. The larvae were found to be susceptible to temephos and Bti. Bioassays on adults demonstrated susceptibility to deltamethrin, suspected resistance to permethrin, and resistance to malathion and bendiocarb. Genotyping revealed low frequencies of heterozygous kdr mutations (V1016G, I1532T, F1534C/S). Synergist assays highlighted the key role of esterases in malathion resistance, a minimal involvement of glutathione S-transferases and an unexpected antagonistic effect of cytochrome P450 monooxygenases. Although larvicides remain effective, resistance to organophosphates, carbamates, as well as suspected resistance to permethrin, has been detected. Esterase-mediated metabolic resistance and kdr mutations may contribute to this profile. These findings highlight the need for resistance monitoring and integrated vector control to ensure sustainable control of Ae. albopictus.

Mosquitoes are significant public health insects responsible for numerous vector-borne diseases. Injudicious chemical use has developed metabolic and genetic resistance in mosquitoes. This study evaluated the repellent efficacy of five essential oils (EOs) from local plants [Mentha spicata I, Ruta tuberculata, Mentha spicata II, Lavandula latifolia, and L. stoechas]. M. spicata I and R. tuberculata EOs were extracted using Clavenger hydrodistillation. Simultaneously, the remaining EOs were obtained through a local extraction distillation unit. Chemical composition was identified using GC-MS. Repellency was assessed using the arm-in-cage method, by rearing Culex pipiens s.l. and Aedes albopictus in the laboratory. Additionally, mixtures containing 15% DEET, 15% IR3535, 5% vanillin, and 10% M. spicata I EO were tested. Both mosquito species were clearly repelled by all EOs. M. spicata I was most potent at 10% concentration. The complete protection time (CPT) at 10% M. spicata I EO was increased using blended mixtures containing 15% DEET, 15% IR35353, or 5% vanillin. Regional variations in M. spicata EOs were detected. This study may serve as a foundation for cosmetic manufacturers and pest control products. Developing botanical and hybrid (natural and synthetic) formulations could provide strong protection against insect bites, particularly from disease-vector mosquitoes, helping to prevent vector-borne diseases.