Mosquito saliva increases disease severity following dengue virus infection.

[ajanta]

Mosquito saliva is known to modulate transmission of some insect-borne pathogens and influence the host immune responses, but its role in dengue disease is not well understood. To investigate it, Michael Schmid and Eva Harris, from the University of California in Berkeley, USA, together with colleagues, studied mice inoculated with DENV alone, or with DENV plus extract from mosquito salivary glands.

http://www.eurekalert.org/pub_releases/2016-06/p-msi060816.php