Arboviruses disrupt salivary gland organization and decrease salivation in Aedes aegypti mosquitoes

Abstract

Aedes aegypti mosquitoes are major vectors for arboviruses. Virus transmission occurs during blood feeding, when infected mosquitoes release both viral particles and saliva. Although saliva proteins can influence viral transmission, their study has been limited by the difficulty of quantifying salivation in natural transmission contexts. Here, we generated a transgenic Aedes aegypti line that secretes fluorescent markers into saliva, enabling direct visualization and quantification of salivation. Using this tool, we found that secretion of saliva reporters is robust across diverse physiological conditions but is markedly reduced following Zika or chikungunya virus infection, both in artificial salivation and mouse feeding assays. In the salivary glands, viral antigens displaced saliva reporters in secretory acinar cells, suggesting a segregation mechanism by which the virus is released independently from salivation. Importantly, diminished release of saliva proteins may contribute to the increased probing behavior observed in infected mosquitoes, which can enhance the chances of virus transmission. Together, these findings suggest that virus-induced suppression of salivation may be an adaptive feature that enhances transmission efficiency.