Determinants of Fine-Scale Heterogeneity in Mosquito-Borne Virus Systems

ABSTRACT Arthropod-borne viruses (arboviruses) are the etiological agents of much morbidity and mortality, especially in low- and middle-income countries. Many of these viruses are spread and maintained by mosquitoes, particularly the urban mosquito Aedes aegypti. Zika virus (ZIKV) is responsible for one of the largest vector-borne disease outbreaks in the past decade, affecting millions in Central and South America including a wave of microcephaly among newborns. Mayaro virus (MAYV) is a mosquito-borne virus endemic to South America and is predicted to become an emergent public health threat. Describing the vector-virus transmission systems are critical for understanding the potential spread of these viruses. Traditionally, laboratory vector competence measures are used to evaluate the ability of a species of mosquito to take up and subsequently transmit an arbovirus by exposing mosquitoes to virus and terminally sampling for the presence of virus in the saliva or peripheral tissues at predetermined time points. However, traditional measures do not assess critical vector-virus interactions that will ultimately impact transmission potential, as these measures focus solely on rates of infectious mosquitoes. My overarching hypothesis is that there are undescribed sources of fine-scale heterogeneity within the vector-virus transmission system that will alter transmission potential. To test this hypothesis, I 1) investigated the impact of the age structure of the mosquito population on the transmission potential of ZIKV by Aedes aegypti, 2) developed a novel method for the quantification of observed heterogeneity among individual mosquitoes, and 3) characterized genotypic diversity among strains of MAYV and the potential impacts on vector competence measurements