Significance of vertical transmission of arboviruses in mosquito-borne disease epidemiology

Abstract

Abstract Mosquito-borne diseases (MBDs) are increasingly prevalent as a result of global change, with significant health and economic impacts worldwide. Dengue virus (DENV), chikungunya virus (CHIKV), Zika virus (ZIKV), yellow fever virus (YFV), Japanese encephalitis virus (JEV) and West Nile virus (WNV) transmitted by Aedes and Culex species have been identified as arboviruses of public health interest. Vertical transmission (VT) which refers to a process where infected mosquitoes transmit viruses to their offsprings have been often overlooked in MBD epidemiology. We conducted a systematic review to evaluate the role of VT in the occurrence, prevenance and spread of MBDs, focusing on study types, mosquito species and virus genera. 175 studies selected from 837 studies between 1950 and 2024 relating to VT in mosquito population were reviewed. Findings revealed that VT occur across multiple mosquito species in natural and experimental settings, with significant variation in VT rates, depending on vector species, virus genus, and study location. Ae. aegypti, Ae. albopictus, Ae. vexans, Cx.pipiens, Cx. tarsalis and Cx. quinquefasciatus were identified as mosquito species that support VT while pathogens identified to be transmitted vertically were DENV, ZIKV, WNV, CHIKV, YFV, Sindbis virus (SINV), Ross River virus (RRV) and Mayaro virus (MAYV). VT rates reported as minimum infection rate (MIR) varied across mosquito species, study type and location. It was also reported that high VT rate may precede mosquito-borne disease outbreak. These findings indicate that VT, though often overlooked, contributes to the dynamics of MBD transmission and could influence disease outbreaks and endemism, especially under changing climatic conditions. These findings also highlight the need to incorporate VT into mathematical models, experimental studies and control strategies, given its potential role in sustaining arbovirus transmission and influencing outbreak dynamics. Graphical abstract