Host inflammatory response to mosquito bites enhances the severity of arbovirus infection

Mosquitoes can pass disease to humans when they bite, which includes infections caused by viruses, known as arboviruses. These viruses infect many millions of people each year and include viruses that cause diseases such as Zika, dengue and chikungunya. Most such infections are usually found in the tropics, but a changing climate and globalization means their range has spread at an alarming rate. Cumulatively these viruses are highly diverse at the genetic level and include up to 90 known human pathogens. It is hard to predict the nature, timing and location of these outbreaks. Furthermore, these viruses replicate to exceptionally high levels in the blood of infected patients. Thus, arbovirus infection constitutes an increasing concern for blood transfusion services. We suggest that it is important to identify common aspects of these infections to aid diagnosis, patient stratification and develop medicines that are applicable to multiple arbovirus infections. An important stage, common to all such infections, is the inoculation of virus at mosquito bites. We have recently shown that mosquito bite inflammation, which is common to all such infections, inadvertently enhances infection. In this study, we identified key aspects of mosquito bite inflammation that are important determinants of the subsequent systemic course and clinical outcome of infection. As such, host responses to mosquito saliva may prove to be a predictor of subsequent disease severity and consequently could also be useful in risk-stratifying blood products