In a study published in the journal
Nature Communications, researchers explored why mosquitoes transmit African strains of the Zika virus more effectively than Asian strains.
They reveal that this difference is based on several specific viral genes and that it is unlikely that the Asian strains, which are solely responsible for human outbreaks, will become as transmissible as the African strains.
Pixabay illustration image
The Zika virus, well-known for causing outbreaks associated with congenital malformations and neurological disorders, is primarily transmitted by the
Aedes aegypti mosquito. It is divided into two main lineages: African and Asian. However, it is observed that mosquitoes transmit African strains of the virus more effectively than its Asian variants. Understanding this difference proves crucial for assessing the risks of future outbreaks and developing effective prevention strategies.
Researchers from the Evolutionary Genomics, Modeling and Health laboratory (GEMS - CNRS / Institut Pasteur) used chimeric viruses, created from genetic constructions where segments of parental genomes are exchanged, to compare these two strains and determine which genes influence transmission.
They thus discovered that several genes are responsible for the efficiency of the virus's passage through the mosquito. The structural genes, which shape the virus's "shell," promote its internalization, while the non-structural genes participate in the replication of the viral genome and the production of infectious particles.
The obtained results are reassuring because they show that it is unlikely that the Asian strains, which are solely responsible for human outbreaks so far, will evolve through simple mutations and become as transmissible as the African strains. By identifying the key genes involved, this research opens perspectives for new therapeutic and prevention targets.
This information will also help better anticipate the virus's future evolution and strengthen the fight against its spread.
Conceptual model of viral infection dynamics in the mosquito. The mosquito image was created in BioRender.
© Shiho Torii