Globalization of trade and travel has increased the introduction of species to new regions, including both mosquito vectors and viruses they transmit. Zika and Chikungunya viruses have been introduced into the Americas in the last five years, and have caused substantial public health concern. In 2016 the executive branch of the US government requested $2.3 Billion to address the novel threat posed by Zika virus. Our aim was to determine the epidemic potential of Zika virus in the USA relative to three other viruses transmitted primarily by the same two mosquito species, Aedes aegypti and Aedes albopictus, dengue, yellow fever, and chikungunya viruses. We integrated data on host viremia and mosquito vector competence, with laboratory data on biting rates and daily survival to estimate all components of transmission potential, R0, except vector abundance.
We found that relative R0 was highest for one serotype of dengue virus (DENV1) and Chikungunya virus and far lower for Zika and yellow fever viruses. Transmission was more efficient by Aedes aegypti mosquitoes than Aedes albopictus because of differences in feeding patterns and survival. Although Zika virus brings new public health challenges to the USA in causing birth defects by infecting the brains of fetuses of pregnant women, out results suggest that Zika outbreaks are likely to be smaller than those by other viruses that have been successfully controlled in the past.