Imma Perfetto
Cosmos science journalist
Larvae of the mosquito responsible for spreading diseases such as dengue, yellow fever and Zika grow faster when exposed to a certain kind of bacteria, according to new research in the Journal of Applied Microbiology.
The finding has important implications for improving programmes to control mosquito populations some of which involve the breeding and mass release of non-biting male mosquitoes that are either sterile or prevent transmission of diseases.
As the changing climate makes environmental conditions increasingly suitable for the transmission of infectious diseases, effectively controlling mosquito populations will become even more critical to mitigating the impacts of climate change on human health.
For example, reported cases of dengue worldwide have increased tenfold in the past 20 years. 2024 is the worst year on record, with than 23 million dengue cases and 8,500 dengue-related deaths reported worldwide as of September.
In the study, bacteria of the genus Asaia were added to the water where mosquito larvae of the globally-distributed species Aedes aegypti developed.
They found that 2 species accelerated the larval development by 1 day. As the larval period of A. aegypti mosquitoes usually lasts about 10 days, accelerating it by a day could mean a valuable boost to mass production.
The exact mechanism for this influence on larval development isn’t yet known. However, it does appear the 2 species created lasting impacts on the larval microbiome.
“Asaia bacteria have been suggested as beneficial parts of mosquito microbiomes, but this has never been rigorously tested in Aedes aegypti,” says the study’s corresponding author, Professor Ben Raymond of the University of Exeter’s Centre for Ecology and Conservation, UK.
“We know that Aedes aegypti mosquito larvae can’t develop at all without a microbiome, and our study shows two Asaia species can play a beneficial role.”
Specifically, they reduced the abundance of species from the genus Pseudomonas and increased the abundance of species from the genus Klebsiella.
The researchers suggest that Klebsiella may have a mutually beneficial relationship with A. aegypti, while Pseudomonas may be mildly parasitic, and that directly testing these relationships would be worthwhile in future work.
