A protein in mosquito spit can keep Dengue virus in check

Mosquito saliva influences transmission of viruses to a bitten mammalian host. For example, it contains factors that dampen the host immune response and so facilitate infection. A study reports on a saliva protein with the opposite effect: D7, a protein present in Aedes aegypti saliva, binds to Dengue virus (DENV) and inhibits its transmission to human cells and mice. Antibodies against D7, which are present in humans exposed to mosquito bites, might therefore facilitate virus transmission and enhance disease severity.