Controlling Emergent Anopheles stephensi in Ethiopia and Sudan (CEASE) Project

The Asian malaria vector An. stephensi has recently been discovered in Africa. We hypothesise that invasive An. stephensi poses a significant malaria risk in urban settings in the Horn of Africa and that this risk can be mitigated through targeted, multi-sectoral vector control combined with rigorous entomological surveillance. 

Key Research Questions   

1.  What was / are the route(s) of invasion of An. stephensi and what is its current and potential future distribution?                                                                              

2.  What is the importance of An. stephensi for malaria transmission in the Horn of Africa?

3.  What are the most effective targeted, multi-sectoral vector control strategies to combat further spread?

Africa is experiencing rapid urbanisation. The UN estimates that 58% of the African population will live in urban areas by 2050. 

• Malaria burden is typically much higher in rural settings, because African malaria vectors are poorly adapted to urban ecologies. 
• An. stephensi, a highly competent vector for both Plasmodium falciparum and P. vivax, formerly confined to South Asia and the Persian Gulf, has recently been identified in the Horn of Africa and is a major threat to malaria control and elimination. 
• An. stephensi was identified in Djibouti in 2012 where it is associated with a significant rise in malaria cases.
• The vector has recently been reported in Ethiopia and Sudan with evidence of natural infections with both P. falciparum and P. vivax in urban settings in Ethiopia.
• There is a critical need to understand the public health impact of An. stephensi; to assess how existing control interventions can be used against it and to develop additional strategies to target urban populations. This is in line with calls from The World Health Organization (WHO) to combat the spread of An. stephensi through intensified vector surveillance and multisectoral vector control.

We take an holistic approach to control invasive An. stephensi in Sudan and Ethiopia by understanding the interactions between the environment, vector, parasite and human host.
The project has 3 work packages: 

Work package 1: Identify the route of invasion of An. stephensi and its current and potential distribution.

a. To update and validate predictive distribution maps enabling us to identify habitats permissive to An. stephensi establishment.
b. Bionomics of invasive An. stephensi in Ethiopia and Sudan.
c. Genomic surveillance of An. stephensi invasions and spread.

Work package 2: Estimate the importance of An. stephensi for malaria transmission.

a. Empirical assessment of the role of An. stephensi for malaria transmission.
b. Identification of the spatial distribution of malaria cases in urban centres.
c. Observational study of entomological and routine malaria morbidity data.
d. Mathematical modelling of the contribution of An. stephensi to malaria transmission.

Work package 3: Evaluate multi-sectoral vector control strategies to combat the spread of An. stephensi.

a. Identify social and ecological factors that could constrain or enhance effectiveness of existing and novel vector control strategies.
b. Conduct pilot testing of vector control tools in laboratory, experimental huts, semi-field systems and/or in communities.
c. Use transmission dynamic model to investigate the public health impact and cost effectiveness of vector control strategies.

Project link

Epidemiology
Social Science
Surveillance
Urban Malaria
Vector Control
Vulnerable Populations

Jan 2021 — Dec 2024

$4.85M

Ethiopia
Sudan

Urban Malaria
Anopheles stephensi