New Strategies to Block Insect-Borne Virus Transmission

Viruses have evolved to infect a variety of host species. Some viruses even employ several hosts to propagate their diseases, such as arboviruses, which use insects to transmit their infections to mammalian hosts such as humans. Understanding how they spread through insects could result in new approaches to prevent their transmission.

In a new study published in the Journal of Virology, researchers discovered the cunning strategies viruses employ to travel among insect hosts and potentially infect other animals. This understanding is especially important when treating viruses that move from insects to humans or livestock, such as Zika, Dengue, and West Nile virus.

The researchers used fruit flies as a model to trace the flow of proteins from two viruses: one that exclusively infects insects and another that can infect insects and other species, including humans.

Even when expressed on their own, without the rest of the virus, these proteins moved to precisely the correct locations in the insect cells. In the insect gut, both proteins traveled to the bottom of the cells, positioning themselves to exit into the insect’s body cavity. In the salivary glands, the insect-only virus protein still went to the cell bottom, but the other protein often moved to the top of the cells–perfectly placed to assemble new virus particles for exit into the saliva, and for infecting a new animal host.”

Gary Blissard, Study Lead Author and Professor, Boyce Thompson Institute

This location is critical to the virus's survival and dissemination. It's as if the proteins have built-in GPS, leading them (and, by extension, the viruses they're associated with) to the exact area where they can continue their lifetime. The researchers discovered that the GPS system was made up of amino acid sequence signals encoded in viral proteins.

These signals were detected by the host’s protein transport mechanisms, which guided the proteins to the virus's preferred site. The researchers also discovered components of the cellular machinery that these viral proteins use to get to their destinations.

This insight could lead to novel methods of blocking the viral proteins' "GPS" or the cellular machinery they use. Thus, viruses might be blocked from entering or exiting the salivary glands, essentially eliminating the virus's capacity to use the insect as a carrier.

Our research highlights the incredible adaptations viruses have evolved to navigate through complex biological systems such as insects. It is a reminder of the continuous evolutionary arms race between viruses and their hosts and the importance of basic research in understanding these intricate biological processes.”

Nicolas Buchon, Study Co-Lead Author and Associate Professor, Department of Entomology, Cornell University

The study reveals the molecular processes behind viral migration in insects, opening up new paths for controlling insect-borne diseases and managing agricultural pests, perhaps leading to improved public health outcomes and crop protection techniques in the future.