Rivera, G. E. | Search bioRxiv

bioRxiv2025

The major role of the REL2/NF-κB pathway in the regulation of midgut bacterial homeostasis in the malaria vector Anopheles gambiae

Multicellular organisms harbor diverse microbial communities that play essential roles in host physiology. While often beneficial, these interactions require tight regulation to prevent dysbiosis and disease. This study examines the tissue-specific immune responses of mosquitoes to blood feeding and Plasmodium falciparum infection in Anopheles females. We demonstrate that REL2 signaling regulates antimicrobial peptide (AMP) expression and shapes midgut bacterial composition post-blood meal. Loss of REL2 leads to midgut dysbiosis, characterized by the overgrowth of Serratia spp., and mosquito lethality within a day of feeding. Interestingly, Serratia-induced dysbiosis also reduces P. falciparum prevalence in surviving mosquitoes. Our findings highlight the critical role of immune system in maintaining midgut bacterial homeostasis and uncover complex interactions between mosquito immunity, gut microbiota, and malaria parasites. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=147 HEIGHT=200 SRC="FIGDIR/small/643338v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@29ddfeorg.highwire.dtl.DTLVardef@ad6037org.highwire.dtl.DTLVardef@87f198org.highwire.dtl.DTLVardef@10640ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2019

Ingested insecticide to control Aedes aegypti: Developing a novel dried attractive toxic sugar bait device for intra-domiciliary control

BackgroundIllnesses transmitted by Aedes aegypti (Linnaeus, 1762) such as dengue, chikungunya and Zika comprise a considerable global burden; mosquito control is the primary public health tool to reduce disease transmission. Current interventions are inadequate and insecticide resistance threatens the effectiveness of these options. Dried attractive bait stations (DABS) are a novel mechanism to deliver insecticide to Ae. aegypti. The DABS are a high-contrast 28 inch2 surface coated with dried sugar-boric acid solution. Ae. aegypti are attracted to DABS by visual cues only, and the dried sugar solution elicits an ingestion response from Ae. aegypti landing on the surface. The study presents the development of the DABS and tests of their impact on Ae. aegypti mortality in the laboratory and a series of semi-field trials. MethodsWe conducted multiple series of laboratory and semi-field trials to assess the survivability of Ae. aegypti mosquitoes exposed to the DABS. For laboratory experiments we assessed the lethality, the killing mechanism, and the shelf life of the device through controlled experiments. In the semi-field trials, we released laboratory-reared female Ae. aegypti into experimental houses typical of peri-urban tropical communities in South America in three trial series with six replicates each. Laboratory experiments were conducted in Quito, Ecuador, and semi-field experiments were conducted in Machala, Ecuador - an area with abundant wild populations of Ae. aegypti and endemic arboviral transmission. ResultsIn the laboratory, complete lethality was observed after 48 hours regardless of physiological status of the mosquito. The killing mechanism was determined to be through ingestion, as the boric acid disrupted the gut of the mosquito. In experimental houses, total mosquito mortality was greater in the treatment house for all series of experiments (p<0.0001). ConclusionsThe DABS devices were effective at killing female Ae. aegypti under a variety of laboratory and semi-field conditions. DABS are a promising intervention for interdomiciliary control of Ae. aegypti and arboviral disease prevention.

ecology↗