P007. Bionomics of Anopheles pseudopunctipennis (Diptera: Culicidae) in the Sierra Tarahumara malaria focus in Northwest Mexico

Abstract

Field studies during the rainy and dry seasons (July–December 2024) investigated the bionomics of Anopheles pseudopunctipennis in the Sierra Tarahumara malaria focus, northwest Mexico. The study characterized ecological variables, including breeding site features, larval densities, biting dynamics, gonotrophic cycle duration, survivorship, host preferences, Plasmodium vivax prevalence, and insecticide resistance by kdr mutation detection. Fieldwork was conducted in Batopilas, Chihuahua, a malaria-endemic area in the Sierra Madre Occidental ravines. Breeding sites were inspected for dimensions, habitat type, physicochemical properties, and immature densities, alongside climatic data. Immature densities averaged eight to fifteen individuals per site, with rock holes and puddles along a river (18 cm to 4 m diameter, minimal vegetation) identified as preferred habitats. Adult mosquitoes were collected via human landing catches (18:00–06:00 hours), with biting rates assessed over 29 nights. 67 resting females were collected and analyzed for blood meal sources using 18S rRNA metagenomics and kdr mutations via Sanger sequencing. Of 735 females collected, 640 were dissected, revealing 68.6% parous and 30.6% nulliparous. The gonotrophic cycle was 2.75 days, shorter than in tropical Mexican populations, suggesting increased biting frequency and malaria transmission potential. A daily survival rate of 0.875 indicated high female longevity, enabling multiple gonotrophic cycles. Host preference was strongly anthropophilic, though other vertebrates were also targeted. In conclusion, this study represents the first comprehensive entomological characterization of the northernmost malaria focus on Mexico. A. pseudopunctipennis drives malaria transmission in northwest Mexico through rock-hole breeding, short gonotrophic cycles, high survival rates, and human preference. Insecticide resistance and female index data are critical for guiding vector control strategies in the region.