Evolution and coevolution of invasive Anopheles stephensi and sympatric Plasmodium populations in Africa: A genomic investigation

ABSTRACT
Anopheles stephensi, a mosquito capable of spreading malaria, is a major threat to the progress
of malaria control. It is a native vector in South Asia and portions of the Middle East but was
reported in Djibouti in 2013 and is now well established throughout East Africa. This invasive
vector is a threat to malaria control because it has the capacity thrive in both urban and rural
areas. In addition, insecticide resistance has been reported across several portions of the invasive
range. Most recently, An. stephensi has been the cause of malaria outbreaks in historically low
transmission regions. There are critical knowledge gaps related to An. stephensi adaptation to
the environment that facilitated its spread and establishment, and the genomic features that
facilitate the compatibility with local Plasmodium falciparum strains. The goal of the proposed
study is to identify the genomic bases of adaptation in invasive An. stephensi in Africa and
An. stephensi’s susceptibility to local African P. falciparum strains. In addition, we will use
these data to develop surveillance tools to better predict An. stephensi’s impact on malaria
epidemiology. This project will continue our long-standing collaborations with academic and
public health institutions in the US, Ethiopia, and Somalia. Ultimately, growing our understanding
of the genomic diversity of An. stephensi will provide the bases for enhanced molecular
surveillance and understanding of risk for future malaria outbreaks across the invasion range.
Our specific aims are: 1) Evaluate the evolution and spread of An. stephensi over the course
of the invasion to identify environmental adaptations, 2) We will identify An. stephensi
genomic features associated with P. falciparum infection. 3) Develop tools to improve the
reporting of epidemiologically relevant genomic markers in An. stephensi. Overall, this
multiregional and interdisciplinary collaborative effort will fill gaps related to invasive An. stephensi
adaptation in East Africa. Our results will provide the scientific bases for approaches to control of
this invasive mosquito and ultimately the prevention of malaria.

Grant Number: 1R56AI192658-01
NIH Institute/Center: NIH
Principal Investigator: Tamar Carter