Anopheles stephensi is a mosquito species that is capable of transmitting both Plasmodium falciparum and P. vivax malaria parasites. It was originally native to South Asia and parts of the Arabian Peninsula but has been expanding its range over the last decade, with detections reported in Djibouti (2012), Ethiopia and Sudan (2016), Somalia (2019) and Nigeria (2020). Although An. stephensi has likely spread to other African countries, it has yet to be detected as systematic, large-scale surveillance of the vector is still in its infancy.

Anopheles stephensi has the capacity to thrive in urban environments, setting it apart from the other main mosquito vectors of malaria that primarily breed in rural areas. Where An. stephensi has been reported in Africa, it has been found to be resistant to many of the insecticides used in public health, posing an added challenge to its control.

The invasion of An. stephensi in sub-Saharan Africa – where the burden of malaria is highest and over 40% of the population lives in urban environments – is particularly worrying. Since 2012, An. stephensi is thought to have contributed to a resurgence of malaria in Djibouti City and at least one outbreak of the disease in Ethiopia. While the overall contribution of An. stephensi to malaria transmission in the region is unclear, the rapid growth of many African cities, coupled with the invasion and spread of this highly efficient and adaptable malaria vector, could undermine the gains made in reducing the burden of the disease.

Access WHO initiative to stop the spread of Anopheles stephensi in Africa