# Fungal microbiota diversity in Aedes, Anopheles and Culex and their potential use as biological tools to control vector-borne diseases, a systematic review

## TL;DR

This paper reviews how fungi in mosquitoes could be used to control diseases like malaria and dengue by blocking pathogens or reducing mosquito survival.

## Contribution

The study systematically reviews fungal microbiota in Aedes, Anopheles, and Culex mosquitoes and their potential for vector control.

## Key findings

- Fungal species like Wickerhamomyces anomalus and Microsporidia MB reduce vector capacity in Anopheles species.
- Fungi inhibit larval development and show antivectorial potential in mosquito organs.
- Ascomycota, Basidiomycota, and Microsporidiomycota are the predominant fungal phyla in mosquitoes.

## Abstract

Mosquitoes harbor diverse and dynamic microbiota which plays a critical role in shaping their development, survival and vector competence. Many studies have focused on the fungal microbiota of mosquitoes to develop new mosquito control strategies and pathogen blocking tools. This review aims to synthesize current knowledge on the composition and functional roles of the mosquito fungal microbiota, highlighting its potential as a tool for innovative vector born disease control strategies.

This review was written in accordance with PRISMA guidelines. Studies on the fungal microbiota of species of the genera
Aedes,
Anopheles, and
Culex and their potential in vector control were searched for in two databases (PubMed, Google Scholar). The quality of the included studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tool. Fungal diversity was investigated according to geographical distribution, mosquito species, identification techniques, developmental stages, and digestive and reproductive organs. We are interested in the antivectorial potential of fungal species.

A total of 32 studies were included in this review after screening 7,458 studies identified through search engines. Most studies on the fungal microbiota of species of the genera
Aedes,
Anopheles, and
Culex were conducted in the United States, Brazil, European countries (France, Italy), and Africa (Kenya). Several fungal genera were isolated in the microbiota, with a predominance in species of the genus
Aedes, followed by
Culex and
Anopheles. The main identification technique used was molecular biology, sometimes combined with culture characteristics. Fungal species were isolated from digestive organs (intestines, intestinal diverticulum, crop), male and female genital organs, and whole specimens at the larval and adult stages. Three phyla (
Ascomycota,
Basidiomycota, and
Microsporidiomycota) were predominant, with yeast-like, filamentous, and intracellular fungal species. Certain fungal strains inhibited the development of larval stages, while other fungal strains (
Wickerhamomyces anomalus,
Microsporidia MB) reduced the vector capacity of
An. stephensi and
An. arabiensis species, respectively.

Mosquitoes harbor diverse fungal microbiota in their organs with antivectorial potential which remain largely unexplored to date. Future research should explore these interactions in greater depth, particularly in organs that have been little studied, such as the salivary glands and stomach, and in regions most affected by vector-borne diseases, such as Africa. These knowledges will enable their use in vector control.

Mosquitoes are known to transmit many diseases such as malaria, dengue, and chikungunya. In absence of effective vaccines and growing concern of resistance to insecticides, researchers are exploring new avenues to limit transmission. One of these involves studying the fungi that live naturally in mosquito bodies to see if they could be used as allies in the fight against these vectors. This study is based on a systematic review. We analyzed 32 scientific articles that met strict selection criteria. Interesting fungi were found at different stages of the mosquito development and in different organs. Certain species were associated with pathogens blocking ability whereas other species slow down larval development and reduce mosquito survival.