- Anopheles funestus is one of the most important malaria vectors in sub-Saharan Africa, ranking alongside Anopheles gambiae as a primary contributor to the transmission of Plasmodium falciparum, the most deadly species of malaria parasite.
- Unlike some other Anopheles mosquitoes, An. funestus is part of a species complex—a group of closely related, morphologically similar species—of which An. funestus sensu stricto is the most significant from a public health standpoint. This species is notable for its strong anthropophilic behavior, preference for indoor feeding and resting, and its long lifespan, all of which make it a highly efficient vector of malaria.
- Morphologically, Anopheles funestus adults are slender mosquitoes with long legs, and their wings bear distinct dark and pale spots that help differentiate them from other mosquitoes. They are typically found in humid, tropical environments, particularly in areas with permanent or semi-permanent bodies of water with vegetation, such as swamps, streams, and riverbanks. These water bodies serve as larval habitats and are generally more stable than the temporary pools favored by An. gambiae, contributing to An. funestus’s role in sustained year-round malaria transmission, especially in regions with perennial water sources.
- An. funestus females are highly anthropophilic, meaning they prefer to feed on humans rather than animals. They are also endophagic (indoor-biting) and endophilic (indoor-resting), which makes them particularly susceptible to indoor-based malaria control strategies like insecticide-treated nets (ITNs) and indoor residual spraying (IRS). However, these interventions have been increasingly challenged by insecticide resistance, particularly to pyrethroids, which are the most commonly used class of insecticides in public health. Resistance in An. funestus populations has become a major obstacle to malaria control in several regions, including southern and eastern Africa.
- The behavioral ecology of An. funestus differs in key ways from that of An. gambiae. While both are deadly vectors, An. funestus tends to prefer more stable and vegetated water bodies for breeding, which makes its populations less dependent on seasonal rainfall and more resilient across different times of the year. Additionally, An. funestus often exhibits delayed biting peaks, which means that people may be bitten indoors during late-night hours, potentially after the protective effect of bed nets has worn off due to sleep movements or exposure during early morning activities.
- As a vector, An. funestus is particularly efficient because of its long lifespan, which increases the likelihood that the malaria parasite can complete its extrinsic incubation period within the mosquito before it dies. This makes each mosquito a more potent transmitter of disease. Furthermore, its preference for feeding on multiple human hosts increases the chances of spreading malaria parasites across households and communities.
- From a control perspective, managing An. funestus requires specialized strategies. Its resistance to common insecticides has prompted efforts to develop next-generation insecticidal tools, such as bed nets treated with non-pyrethroid insecticides or synergists that block detoxification enzymes in mosquitoes. Additionally, larval source management is being revisited in areas where breeding habitats are accessible and relatively few, such as irrigation zones and marshlands.
