Viral adaptations to vector-borne transmission can result in complex host-vector-pathogen interactions.

Research Highlight: Norton, A. M., Remnant, E. J., Tom, J., Buchmann, G., Blacquiere, T., & Beekman, M. (2021). Adaptation to vector-based transmission in a honeybee virus. Journal of Animal Ecology, 90, https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.13493. In their paper on the adaptation to vector-based transmission via the mite Varroa destructor in a honeybee virus, Norton et al. study how high versus low levels of a viral vector affect viral load and potential competition between two strains of Deformed Wing Virus, an important highly virulent bee virus with the potential to spill-over into other pollinators and bee-associated insect species. This paper addresses two very timely issues, on the one hand on viral evolutionary ecology in response to vector-borne transmission, and on the other hand providing much needed information on an important honey bee pathogen. Using a complex natural system, this study shows that vector-borne transmission, and the control of the vector, can select for complex host-pathogen-vector interactions and that adaptations to changing transmission landscapes in fast evolving pathogens can create conditions for emerging pathogens to transition to endemic diseases.