Why do viruses not kill the mosquitoes that transmit them?

Arboviruses need mosquitoes to pass from one person to another. But… if these viruses can damage human cells, why do they not also destroy the cells of the mosquitoes that carry them?

A study led by the Molecular Virology Group at the Department of Medicine and Life Sciences, Pompeu Fabra University (MELIS-UPF), directed by Juana Díez, suggests that, inside mosquito cells, the virus can limit the production of viral proteins. In other words, it can “turn down the volume” of its own activity.

The infographic compares what happens when an arbovirus infects other hosts and when it infects mosquito cells. In other hosts, increased translation of viral RNA produces more viral proteins and more cell damage. In the mosquito, this translation is repressed, fewer viral proteins are produced and the cell remains intact. This balance may help the virus persist inside the mosquito and continue to be transmitted.

Key concepts:

What is an arbovirus? An arbovirus is a virus transmitted by arthropods, such as mosquitoes or ticks. Examples include dengue, chikungunya and West Nile virus.
What does RNA “translation” mean? Translation is the process by which the cell reads the information in RNA and produces proteins. During an infection, some viruses use this process to produce their own viral proteins.

Turning down the volume of viral activity

The work, published in PLOS Biology, shows that in mosquito cells the virus can accumulate viral RNA, but does not necessarily translate it into large amounts of proteins. In other words: the virus remains present, but its activity is partially controlled. This process is known as translational repression.

If the virus rapidly destroyed the mosquito’s cells, it would also lose its vehicle for transmission. This is why the virus uses translational repression, allowing it to maintain a persistent infection and remain inside the insect without causing immediate damage.

Reference article

Talló-Parra M, Puig-Torrents M, Pérez-Vilaró G, Ribó Pons S, Díez J. Translational repression of viral RNAs supports persistent arbovirus infection in mosquitoes. PLOS Biology (2026).

About the author

Sonia Liñán has over 20 years’ experience in science communication. She believes communication is a powerful tool for social change and works to make research clearer, more engaging, more diverse, and more inclusive. She is currently Coordinator of Digital Media and Scientific Affairs at PRBB. Previously, she led communications for the EMBIMOS research group (ICM-CSIC), was part of the coordination team behind the MINKA citizen-science observatory, and headed the Digital Marketing and Communications team at Biocat. More information on LinkedIn.