Anopheles stephensi is a primary mosquito vector of malaria in urban India and is included in the same subgenus as Anopheles gambiae, the primary malaria vector in Africa. A. gambiae consists of a complex of morphologically identical species of mosquitoes, along with all other major malaria vectors; however, A. stephensi has not yet been included in any of these complexes. Nevertheless, two races of A. stephensi exist based on differences in egg dimensions and the number of ridges on the eggs; A. s. stephensi sensu stricto, the type form, is a competent malaria vector that is found in urban areas, and A. s. mysorensis, the variety form, exists in rural areas and exhibits considerable zoophilic behaviour, making it a poor malaria vector. However, A. s. mysorensis is a detrimental vector in Iran. An intermediate form also exists in rural communities and peri-urban areas, though its vector status is unknown.About 12% of malaria cases in India are due to A. stephensi.
In November 2015, an American research group demonstrated that an A. stephensi with genetic modifications could be rendered incapable of transmitting malaria, and that 99.5% of the mutant mosquitoes' offspring were also immune.
