Anopheles Mosquito (Malaria Vector)

Genus Anopheles — the malaria mosquitoes — contains about 460 species worldwide, of which 30-40 are competent vectors of human Plasmodium parasites (the protozoans that cause malaria). Anopheles gambiae is the most efficient vector and dominates malaria transmission across sub-Saharan Africa, where the global malaria burden is concentrated. Anopheles mosquitoes are distinguished from non-malaria Culex and Aedes mosquitoes by several anatomical features: the resting posture is at an upward tilted angle (head-down/abdomen-up), with the body in a single straight line from proboscis to abdomen-tip; non-Anopheles mosquitoes rest with the body parallel to the substrate. Eggs are laid singly on water (with characteristic lateral floats), not in rafts or on container walls. The species feeds at dusk and during the night, with peak biting activity 1-3 hours after sunset. Plasmodium transmission requires a complex cycle: an infected human is bitten by an Anopheles, the parasite undergoes sexual reproduction in the mosquito's gut over 10-14 days, then migrates to the salivary glands, from which it is injected into the next human bitten. Malaria has shaped human evolution more than any other infectious disease — the heterozygous sickle-cell trait, the Duffy antigen-negative blood type, hereditary thalassemia, and G6PD deficiency are all malaria-resistance polymorphisms maintained by selection in malaria-endemic populations. WHO estimates 247 million annual malaria cases and 619,000 annual malaria deaths (2021), the vast majority in children under 5 in sub-Saharan Africa. The 2022 approval of the first malaria vaccine (RTS,S/AS01) for children in moderate-to-high transmission zones is a landmark in malaria control.