VVN and Tick Salivary Glands- Understanding Tick Transmission

The National Institute of Health recently published a study investigating the transmission of tick-borne viruses. Tick salivary glands are intended to prevent the transmission of disease, but for some reason this is not the case with viruses. In this case the researchers examined tick-borne flaviviruses,  which include viruses that cause diseases like dengue fever, Zika, West Nile, and yellow fever (among others). 

They found that the viruses reside in specific cells in the salivary glands, and that the viral levels increase when the ticks are fed. There are also differences in levels between female and male ticks, and there is a marker for a gene that helps with infection. This gene, named VVN, is found in the tick organ where viruses are transmitted. When transcription of VVN was reduced, there was a reduced overall virus production in the tick. 

Learning more about viral tick-borne illnesses and the exact method and locale of transmission can help us understand and prevent further spread of these diseases. 

https://mbio.asm.org/content/10/1/e02628-18/figures-only

-Anja Zehfuss 1/30