Physicochemical Properties of Anopheles Mosquito Larval Habitats in Nouakchott, Mauritania

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.