Area B Transmission

PROGRAM PROJECT 2 [PP2]: Bionomics, Ecology, & Control of An. stephensi (BECA) against the background of endemic primary and secondary anopheline vectors. ABSTRACT/SUMMARY The introduction of Anopheles stephensi Liston (AS) to Djibouti and Ethiopia - evidence of further expansion of AS inland into Sudan, across the strait to Yemen and more recently into Kenya, Nigeria, and Ghana― has justifiably raised "alarm bells". Between 2013-2017, following the introduction of AS to Djibouti, national surveys have indicated that the number of malaria cases have increased significantly across the country, supported by recent entomological surveys that indicate AS infections with Plasmodium falciparum (Pf) and P. vivax (Pv). AS has demonstrated preference for similar breeding habitats as the urban dengue vector Aedes aegypti. Therefore, the risk of a return of malaria into highly dense, urbanized cities and towns in Nigeria, Cameroon, and throughout Sub-Saharan Africa (SSA) is concerning. Evidence from Ethiopia suggested that AS in the Somali region are also resistant to pyrethroid-based insecticides. The overarching hypothesis to be explored in PP2 is that multiple introductions of AS was likely due to overland commercial traffic/transhumance and via seaports of entry (e.g., in the case of Accra, Ghana) and that these introductions and subsequent successful establishment are influenced by habitat suitability (invasibility). The project will leverage innovative technology to extensively map and characterize AS vector genomics and bionomics in Central and West Africa that will allows us to answer four priority questions viz. AS invasion of SSA: (i) Where did invasive AS populations originate from and are there continuous introductions?; (ii) How long have AS populations been established in different locations?; (iii) What are the necessary/optimal conditions supporting AS establishment?; and (iv) What is the potential contribution of AS to malaria transmission in study locales? Therefore, this Émergents ICEMR program project seeks to: Aim PP2.1. Conduct a cross-national comprehensive mosquito genomic surveillance program to hunt for and characterize invasive An. Stephensi; Aim PP2.2. Geospatial analyses of AS strain biology and micro- ecologies to quantify habitat suitability or invasibility to enable predictions for AS spread; and Aim PP.2.3 Mosquito speciation, insecticide resistance, and infection status using a field-deployable Matrix- assisted laser desorption/ionization mass spectrometry (MALDI-MS). Key outcomes of PP2 are to (i) develop a predictive model for An. stephensi invasion into non-endemic sites by understanding the microecology including the role of sympatric non-anopheline mosquito vectors, (ii) determine the prevalence of Pf, NFM, and Pf-NFM mixed sporozoite infections in anopheline vectors (AS included) in surveyed sites; (iii) validate an artificial intelligence-driven smart trap; and (iv) establish an "all-in-one" LMIC-deployable MALDI analytical platform for determining vector species, insecticide resistance and malaria parasite infection status.