Aedes aegypti mosquitoes are established throughout Nouakchott, Mauritania, where its insecticide resistance status is unknown and dengue has become endemo-epidemic since 2014. Eggs were collected using ovitraps at 12 sites in five districts of Nouakchott, in August 2024. Adult females and larvae of the F1 generation were used for bioassays. Permethrin, deltamethrin, bendiocarb, and malathion were evaluated at discriminating concentrations. Larval assays were carried out at seven concentrations with Bacillus thuriengensis var israelensis (Bti) and temephos. The presence of knockdown resistance (kdr) mutations known to be associated with pyrethroid resistance was assessed by polymerase chain reaction and amplicons sequencing. Adults showed high levels of resistance to all insecticides tested. Larvae were susceptible to Bti (LD50 < 50 µg/L) and temephos (LD50% = 6.8 ± 0.7 µg/L). Only three kdr point mutations, S989P, V1016G, and F1534C, were found. The tri-locus genotypes SP/VG/FC were significantly associated with pyrethroid survival while only the tri-locus genotypes PP/GG/FF showed significant association with deltamethrin resistance. Given their level of insecticide resistance, there is an urgent need to control Ae. aegypti populations by several methods, including the use of biological larvicides, physical elimination of peridomestic breeding sites, water drainage, and public education to prevent arbovirus transmission.

Aedes aegypti, the main urban vector of dengue fever, represents a growing public health problem in Nouakchott, the capital of Mauritania. Identifying the factors influencing the distribution and productivity of its breeding sites is essential for the development of effective control strategies. From May 2023 to April 2024, physico-chemical characteristics were recorded and mosquito larvae were collected, using a standard dipping method, from 60 water collections each month during the dry season and twice a month during the rainy season, totaling 294 observations. The larval positivity of water collections and larval abundance of breeding sites over the time were modeled using a random-effect logistic regression model and a negative binomial regression model, respectively. The depth, distance from habitat, type of water collection and exposure to sunlight were statistically significant and independently associated with water collection positivity for Ae. aegypti larvae (aOR = 5.18, 95%CI [1.66–16.18], p-value = 0.005; aOR = 0.00, 95%CI [0.00–0.02], p-value < 0.001; aOR = 252.88, 95%CI [4.05–15,786.84], p-value = 0.009 and aOR = 0.04, 95%CI [0.01–0.26], p-value < 0.001, respectively). Aedes aegypti larval habitats were mainly artificial (90%), temporary (n = 217 observations), close to dwellings (n = 114) and shaded (n = 96). Plastic water tanks (n = 17, 48.6%), wells (n = 6, 17.1%) and barrels (n = 4, 11.4%) were the most common breeding sites. Larval abundance was negatively associated with containers of increasing pH and surface area (aOR = 0.50, 95%CI [0.33–0.75] p-value = 0.001 and aOR = 0.48, 95%CI [0.27–0.87], p-value = 0.016, respectively). As Ae. aegypti mosquitoes are multi-resistant to adult insecticides and dengue has become endemo-epidemic since 2014, vector control should give the priority to the physical removal or treatment of shaded, peridomestic containers—particularly plastic water tanks and barrels—and consider the use of biological larvicides to target breeding sites with low pH and small surface areas.

Malaria remains one of the main public health problems in Mauritania, and it is essential to identify the factors that determine the distribution and productivity of Anopheles breeding sites in order to develop more effective control strategies. A longitudinal survey with repeated measurements was conducted in Nouakchott between May 2023 and April 2024, in order to examine the factors influencing the distribution and productivity of Anopheles larval habitats. The larvae were collected by immersion in 60 water points, once a month during the dry season and twice a month during the rainy season, for a total of 294 observations. The physical and chemical characteristics of the sites were also measured. Logistic regression analyses with random effects showed that the presence of Culex and Aedes larvae, pH, and temperature were statistically significantly associated with positive water collection for Anopheles larvae (aOR = 3.03, 95%CI [1.14–8.07], p-value = 0.026; aOR = 0.18, 95%CI [0.05–0.60], p-value = 0.006; aOR = 3.17, 95%CI [1.32–7.61], p-value = 0.010 and aOR = 5.95, 95%CI [2.09–16.92], p-value < 0.001, respectively). Only Anopheles multicolor and An. arabiensis were present in Nouakchott. Our results could help health authorities by guiding the destruction of breeding sites with biological larvicides or physical elimination of peridomestic habitats.

Schistosomiasis is a major neglected tropical disease in sub-Saharan Africa. This study compared the epidemiology of urinary schistosomiasis among children living in two distinct ecosystems in Mauritania: the Senegal River Basin (Trarza region) and the arid oasis areas (Adrar and Tagant regions). A cross-sectional study was conducted between February 2023 and February 2024 involving 856 children across 14 sites. Urine samples were collected from school-aged children and subjected to macroscopic and microscopic examinations. A questionnaire was administered to each child to determine sociodemographic factors. Environmental and geographical factors were documented in the localities. The prevalence rate of urinary schistosomiasis among children in the Senegal River Valley was 32.4%. In the oases zone, prevalences were 6.43% and 3.35% in Tagant and Adrar, respectively. Macroscopic hematuria was 29.1%, 6.04%, and 4.18% in Trarza, Adrar, and Tagant, respectively. The intensities of infection were 48.9, 6.43, and 40 eggs/10 mL in the Trarza, Adrar, and Tagant regions, respectively. Based on sex, prevalence was higher among boys in the Trarza and Tagant regions, while in Adrar, it was higher among girls. Prevalence among children using polluted water sources with dense vegetation in the department of Tékane, in the Trarza region, was significantly higher (35.7%) than among those using cleaner water sources (21%). Urinary schistosomiasis remains highly prevalent among children living along the Senegal River, while considerably lower transmission was observed in oasis settings. These findings highlight the strong influence of environmental and water-related factors on transmission dynamics and underscore the need for targeted, context-specific control strategies.

Aedes aegypti, the main urban vector of dengue fever, poses a major public health problem in Nouakchott, Mauritania. This study analyzed the host-seeking and sugar-feeding behaviors of Ae. aegypti. Mosquitoes were collected using a vacuum cleaner in four districts between December 2023 and October 2024. Biting activity on humans was studied in May 2024, exclusively in the districts of Ksar, Tevragh Zeina and Arafat, between 5:00 a.m. and 9:00 p.m. A negative binomial model was performed to analyze the effect of location and time on the human biting rate (HBR) of mosquitoes. In Nouakchott, except in the Arafat district, Ae. aegypti bites occur mainly outdoors, between 8:00 a.m. and 1:00 p.m., with a peak between 11:00 a.m. and noon (HBR = 20 bites/person), and between 5:00 p.m. and 7:00 p.m., with a peak between 6:00 p.m. and 7:00 p.m. (HBR = 11 bites/person). Inside homes, Ae. aegypti biting activity remains low everywhere (HBR ≤ 1.5 bites/person/hour). Molecular analysis of the origin of the blood meals showed that the females collected in Nouakchott were exclusively anthropophilic. Molecular analysis of the sugar sources revealed a great diversity with sweet potato being among the most common. These results highlight the need for targeted outdoor interventions and larval control measures to reduce the risk of dengue transmission in Nouakchott.