Mosquito Microbes That Block Malaria Parasites Reviewed in New Systematic Analysis

A systematic review published in Frontiers in Insect Science examines how the bacteria and other microbes that live inside Anopheles mosquitoes interfere with the development of Plasmodium falciparum sporozoites, the parasite stage that makes mosquitoes capable of transmitting malaria.

The authors searched PubMed, Scopus and Google Scholar for studies published between 2000 and 2026, and 41 studies met their inclusion criteria. Data were extracted and synthesized as a narrative following the PRISMA guidelines, and the risk of bias in the included animal studies was assessed with SYRCLE’s tool. The review is currently listed as an accepted manuscript, with the final formatted version to be published by the journal.

Across the synthesized evidence, the effect of the microbiota on sporozoite development emerged as strongly dependent on the specific microbial strain, the mosquito species involved and the experimental context. Rather than a single uniform mechanism, the review found a patchwork of interactions, some of which dramatically suppress the parasite while others show no measurable effect at all.

According to the review, the wAlbB strain caused a 3.4- to 3.7-fold decrease in sporozoite numbers, while wAnga-Mali showed a negative correlation with sporozoite presence in 95% of the examined cases. By contrast, the wAnmo strain in Anopheles moucheti showed no correlation with sporozoite outcomes, underscoring that even closely related bacterial strains can differ sharply in their impact on parasite development.

Microsporidia MB was reported across African settings, with prevalence ranging from 1% to 57% and no fitness costs for the mosquito host, according to the review.

Among bacterial candidates, the review highlighted Serratia ureilytica strain Su_YN1, which inhibited approximately 98% of parasites. The reported mechanism involves outer membrane vesicles loaded with AmLip, which target the parasite via the phosphatidylcholine scavenging pathway.

Engineered symbionts combining transgenesis and paratransgenesis achieved 93% transmission blocking in mouse models, according to the review.

The authors conclude that the mosquito microbiota plays a significant but strain-, species- and context-dependent role in P. falciparum sporozoite development. They identify Microsporidia and Serratia species as promising candidates for field deployment, positioning them as sustainable, environmentally friendly complements to chemical insecticides for malaria vector control.

As with any systematic review, the findings synthesize existing research rather than presenting new experimental results, and the reported effects derive from studies of varying designs, mosquito species and laboratory or field conditions. The authors’ assessment of risk of bias using SYRCLE’s tool reflects the fact that much of the underlying evidence comes from animal studies, and the review’s conclusions about field deployment remain forward-looking statements about candidate microbes rather than demonstrated outcomes of large-scale interventions.

Subject of Research: The role of mosquito microbiota in blocking Plasmodium falciparum sporozoite development in Anopheles mosquitoes

Article Title: Microbiota-mediated blocking of plasmodium falciparum sporozoites in Anopheles: a systematic review

Article References: Olafusi, C. O., Tebamifor, M. E., Bejapade, T. I., Afolabi, I. S., & Ogunlana, O. O. (2026). Microbiota-mediated blocking of plasmodium falciparum sporozoites in Anopheles: a systematic review. Frontiers in Insect Science, 6, Article 1958166. https://doi.org/10.3389/finsc.2026.1958166

Image Credits: AI Generated

DOI: 10.3389/finsc.2026.1958166

Keywords: malaria, Anopheles, Plasmodium falciparum, sporozoites, microbiome, Wolbachia, Microsporidia MB, Serratia, paratransgenesis, systematic review, vector control, salivary gland