AbstractBecause of the increasing threat that Zika virus (ZIKV) poses to extra-tropical regions due to increased global travel, there is a need for better understanding of the effect(s) of temperature on the establishment potential of ZIKV within these subtropical, temperate, and/or seasonal Ae. aegypti populations. The first step to determining risk establishment of ZIKV in these regions is to assess ZIKV’s ability to infect mosquitoes at less tropical temperatures, and thus be detected through common surveillance programs. To that end, the effect of two rearing temperatures (RT) and extrinsic incubation temperatures (EIT) on infection and dissemination rates was evaluated, as well as the interactions of such. Total, there were four combinations (RT24-EIT24, RT24-DEI28, RT28-EIT24, RT28- EIT28). Further, a stochastic SEIR framework was adapted to determine whether observed data could lead to differential success of establishment of ZIKV in naive mosquito populations. There was no consistent pattern in significant differences found across treatments for either infection or dissemination rates (p>0.05), where only a significant difference was found in infection rates between RT24- EIT24 (44%) and RT28-EIT24(82.6%). Across all temperature conditions, the model predicted between a 77.3% and 93.1% chance of successful establishment of ZIKV in naive mosquito populations under model assumptions. Further, the model predicted between 4.1% and 46.7% chance of at least one mosquito developing a disseminated infection, depending on temperature conditions, despite no significant differences in the experimental data. These results indicate that 1) there is no straightforward relationship between RT, EIT, and infection/dissemination rates for ZIKV, similar to what has been reported for DENV, 2) in more temperate climates, ZIKV may still have the ability to establish in populations of Ae. aegypti, and 3) despite a lack of statistical differences in observed experimental data, model predictions indicate that the interplay of rearing and extrinsic incubation temperatures may still alter the kinetics of ZIKV within the mosquito enough to affect numbers of infected/disseminated mosquitoes and the associated probability of detection through surveillance programs.
Investigating the probability of establishment of Zika virus and detection through mosquito surveillance under different temperature conditions
