Development of an infection via sugar meal (IVSM) technique to infect mosquitoes (Diptera: Culicidae) with arthropod-borne viruses

The global expansion of mosquito vectors is increasing human exposure to arboviruses, highlighting the need for rapid and practical approaches to assess vector competence. Standard artificial laboratory infection methods rely on infectious blood meals or intrathoracic inoculation, both of which can be resource-intensive and limit the capacity to conduct timely experiments, particularly in high-containment facilities. We developed an infection via sugar meal (IVSM) technique to determine whether mosquitoes can acquire and transmit arboviruses by ingesting virus-spiked sucrose. Using IVSM, we tested the vector competence of Aedes albopictus and Culex quinquefasciatus for West Nile virus (WNV), Mayaro virus (MAYV), and Zika virus (ZIKV) following 1-hour or 24-hour exposures. Viral RNA copy numbers were quantified in the body, legs/wings, and saliva at 7 and 10 days post-infection. Both species supported WNV infection and dissemination, with the virus detected in saliva. Aedes albopictus exhibited high MAYV infection and dissemination rates, whereas Cx. quinquefasciatus was largely refractory. ZIKV infection and dissemination were limited in both species and did not progress to saliva. High feeding success, low vector mortality, and reproducible outcomes across trials demonstrate that IVSM is an accessible and practical alternative to blood-based infection models and provides a framework for investigating vector competence under conditions that utilize natural feeding behavior.