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Recurrence of local transmission of Zika virus in Puerto Rico is a major public health risk to the United States, where mosquitoes Aedes aegypti(Linnaeus) and Aedes mediovittatus(Coquillett) are abundant. To determine the extent to which Ae. mediovittatusare capable of transmitting Zika virus and the influence of viremia, we evaluated infection and transmission in Ae. mediovittatusand Ae. aegyptifrom Puerto Rico using serial dilutions of infectious blood. Higher doses of infectious blood resulted in greater infection rates in both mosquitoes. Aedes aegyptifemales were up to twice as susceptible to infection than Ae. mediovittatus, indicating a more effective midgut infection barrier in the latter mosquito species. Aedes aegyptiexhibited higher disseminated infection (40–95%) than Ae. mediovittatus(<5%), suggesting a substantial midgut escape barrier in Ae. mediovittatus. For Ae. aegypti, transmission rates were low over a range of doses of Zika virus ingested, suggesting substantial salivary gland barriers.

Zika virus (ZIKV) first spread into Brazil in 2013 and is now present throughout the Americas. In 2016, Florida witnessed the beginnings of local ZIKV transmission. No reports of local transmission have been reported for 2018; however, travel related cases continue to be reported. Recurrence of local transmission in the United States is a major public health risk in Florida where vectors Aedes aegypti(Diptera: Culicidae, Linnaeus) and Aedes albopictus(Diptera: Culicidae, Skuse) are abundant and there is a high potential for virus reintroduction. A dose-response study was used to evaluate susceptibility and transmission potential of Florida Ae. aegyptiand Ae. albopictusto ZIKV originating from Puerto Rico. Mosquitoes were orally exposed to one of three doses of ZIKV. Higher doses of infected blood resulted in overall greater infection rates in both mosquito species. Ae. aegyptiand Ae. albopictuswere susceptible to infection with ZIKV and revealed a significant species by dose interaction. At low doses, Ae. aegyptiwas significantly less susceptible to infection with ZIKV than Ae. albopictus(6.7% and 44.4%, respectively). In contrast, at high doses, Ae. aegyptiwas significantly more susceptible to infection than Ae. albopictus(75.8% and 53.8%, respectively). No significant differences were observed between Ae. aegyptiand Ae. albopictusin disseminated infection (0–75%) and saliva infection (0–52.4%). These observations suggest greater susceptibility to infection for Ae. albopictusat lower doses likely encountered by viremic humans. However, low disseminated infection and saliva infection for Ae. albopictus, combined with catholic feeding behavior, are likely to limit transmission potential relative to Ae. aegypti.