The Anopheles stephensi mosquito is an invasive malar-
ia vector recently reported in Djibouti, Ethiopia, Sudan,
Somalia, Nigeria, and Ghana. The World Health Orga-
nization has called on countries in Africa to increase
surveillance efforts to detect and report this vector and
institute appropriate and effective control mechanisms.
In Kenya, the Division of National Malaria Program con-
ducted entomological surveillance in counties at risk for
An. stephensi mosquito invasion. In addition, the Ke-
nya Medical Research Institute conducted molecular
surveillance of all sampled Anopheles mosquitoes from
other studies to identify An. stephensi mosquitoes. We
report the detection and confirmation of An. stephensi
mosquitoes in Marsabit and Turkana Counties by using
endpoint PCR and morphological and sequence identi-
fication. We demonstrate the urgent need for intensified
entomological surveillance in all areas at risk for An.
stephensi mosquito invasion, to clarify its occurrence
and distribution and develop tailored approaches to pre-
vent further spread.