In a2019 vector alert, WHO identified the spread ofAnopheles stephensias a significant threat to malaria control and elimination – particularly in Africa, where the disease hits hardest. Anew WHO initiative, launched today, aims to stop the further spread of this invasive mosquito species in the region.

Originally native to parts of South Asia and the Arabian Peninsula,An. stephensihas been expanding its range over the last decade, with detections reported in Djibouti (2012), Ethiopia and Sudan (2016), Somalia (2019) and Nigeria (2020). Unlike the other main mosquito vectors of malaria in Africa, it thrives in urban settings.

With more than 40% of the population in Africa living in urban environments, the invasion and spread ofAn. stephensicould pose a significant threat to the control and elimination of malaria in the region. But large-scale surveillance of the vector is still in its infancy, and more research and data are urgently needed.

"We are still learning about the presence ofAnopheles stephensiand its role in malaria transmission in Africa," said Dr Jan Kolaczinski, who leads the Vector Control and Insecticide Resistance unit with the WHO Global Malaria Programme. "It is important to underscore that we still don't know how far the mosquito species has already spread, and how much of a problem it is or could be."

WHO's new initiative aims to support an effective regional response toAn. stephension the African continent through a five-pronged approach:

increasing collaborationacross sectors and border; strengthening surveillanceto determine the extent of the spread ofAn. stephensiand its role in transmission; improving information exchangeon the presence ofAn. stephensiand on efforts to control it; developing guidancefor national malaria control programmes on appropriate ways to respond toAn. stephensi prioritizing researchto evaluate the impact of interventions and tools againstAn. stephensi

Integrated action is "key to success"

Where feasible, national responses toAn. stephensishould be integrated with efforts to control malaria and other vector-borne diseases, such as dengue fever, yellow fever and chikungunya. TheWHOGlobal vector control response 2017–2030provides a framework for investigating and implementing such integration.

"Integrated action will be key to success againstAnopheles stephensiand other vector-borne diseases," noted Dr Ebenezer Baba, malaria advisor for the WHO African Region. "Shifting our focus to integrated and locally adapted vector control can save both money and lives," he added.

Tracking the spread ofAnopheles stephensi

The WHOMalaria Threats Mapfeatures a dedicated section on invasive vectors, includingAn. stephensi. All confirmed reports of the presence ofAn. stephensishould bereported to WHOto allow an open sharing of data and an up-to-date understanding of its distribution and spread. This knowledge will ultimately provide a basis to assess the effectiveness of any efforts to control or eliminateAn. stephensi.

Distributed by APO Group on behalf of World Health Organization (WHO).