The arrival of the warm season in Europe brings with it an increase in mosquito activity, which can be quite bothersome for humans. While mosquitoes and their larvae play a vital role in the ecosystem as prey for many animals, they can also pose a danger to humans by transmitting diseases such as Zika and West Nile viruses. In recent years, invasive mosquito species from tropical and Asian regions have been making their way into Central Europe, facilitated by global trade and climate change. These mosquitoes, such as the Asian tiger mosquito, Japanese bush mosquito, and yellow fever mosquito, are capable of carrying tropical diseases like dengue and yellow fever.
Controlling the spread of these invasive mosquito species is not only a technological challenge but also a socio-political one. Regulations and laws, particularly those stemming from the German government’s “Insect Protection Action Program,” impose restrictions on the use of pesticides in and around water bodies. Furthermore, the release of genetically modified mosquitoes is met with resistance from the majority of the population. Therefore, finding the best approach to protect human health while considering environmental concerns becomes crucial.
In a recent article published in Biotechnology Advances, a consortium of scientists from the Hessian LOEWE Center for Translational Biodiversity Genomics in Germany, along with their partner institutions, present a new technology they have developed to address this dilemma. Their objective is to create a “fire brigade” against mosquito-borne tropical diseases.
The first step involves efficient monitoring of mosquito spread and virus presence using genetic analysis of water samples, known as “environmental DNA.” The research team has already sequenced the genomes of various immigrant mosquitoes, allowing them to develop reliable detection methods similar to PCR tests. The second step involves the use of a novel technology called “RNA interference.”
In this process, mosquito larvae in the affected areas are provided with food containing double-stranded ribonucleic acids (RNAs). These molecules, found in every living organism’s cells, exert their effect through the larvae’s intestine, targeting and silencing crucial survival genes. Professor Miklós Bálint, an author of the study and expert in Functional Environmental Genomics, explains that the advantage of this method is its specificity to the targeted mosquito species, posing no threat to other insects or humans. Additionally, there are no toxic residues left in the environment during RNA degradation, and the technique does not involve the release of genetically modified mosquitoes capable of reproducing.
Currently, the consortium is researching the development of double-stranded RNAs that are highly effective in controlling mosquitoes and the viruses they carry. Another significant challenge is finding an appropriate formulation for the RNA molecules, one that does not degrade too quickly in the environment and can be absorbed by water-dwelling mosquitoes in the form of particles. This packaging aspect is being addressed by Professor Andreas Vilcinskas, who leads the Bioresources section at the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Giessen.
Professor Vilcinskas coordinates the establishment of the “fire brigade” against invasive mosquitoes at the LOEWE Center TBG and its partner institutions, including Goethe University Frankfurt am Main, Justus Liebig University Giessen, the Senckenberg Society for Nature Research, the Institute for Social-Ecological Research (ISOE) in Frankfurt, and the Institute of Tropical Medicine in Antwerp, Belgium.
The publication highlights the potential of RNA interference (RNAi) as an innovative and environmentally friendly technology for controlling disease-carrying organisms, also known as vectors. RNAi-based sprays are also being developed as an eco-friendly alternative to conventional pesticides for combating insect pests like the Colorado potato beetle and are expected to enter the market soon.