International travelers and genomics uncover a ‘hidden’ Zika outbreak

Nathan D. Grubaugh; Sharada Saraf; Karthik Gangavarapu; Alexander Watts; Amanda L. Tan; Rachel J. Oidtman; Jason T. Ladner; Glenn Oliveira; Nathaniel L. Matteson; Moritz U.G. Kraemer; Chantal B.F. Vogels; Aaron Hentoff; Deepit Bhatia; Danielle Stanek; Blake Scott; Vanessa Landis; Ian Stryker; Marshall R. Cone; Edgar W. Kopp; Andrew C. Cannons; Lea Heberlein-Larson; Stephen White; Leah D. Gillis; Michael J. Ricciardi; Jaclyn Kwal; Paola K. Lichtenberger; Diogo M. Magnani; David I. Watkins; Gustavo Palacios; Davidson H. Hamer; Lauren M. Gardner; T. Alex Perkins; Guy Baele; Kamran Khan; Andrea Morrison; Sharon Isern; Scott F. Michael; Kristian G. Andersen

Temperature is an important predictor of Ae. aegyptiborne virus transmission, as it affects mosquito population sizes (i.e. mosquito development, survival, and reproduction rates), interactions between mosquitoes and human hosts (i.e. biting rates), and mosquito transmission competence (i.e. mosquito infection and transmission rates) (Caminade et al., 2016; Mordecai et al., 2017; Siraj et al., 2017) . Virus transmission by Ae. aegypti can occur between 18-34°C and peaks at 26-29°C (Mordecai et al., 2017) . To assess yearly and seasonal variations in Ae. aegypti transmission potential for dengue and Zika virus, we used a temperature-dependent model of transmission using a previously developed R 0 framework (Mordecai et al., 2017) . By focusing this analysis on Havana, we controlled for spatial drivers of transmission and thereby isolated a representative example of temporal patterns in transmission potential. Using hourly temperature data obtained from OpenWeatherMap (https://openweathermap.org/), we calculated monthly mean temperature and used it to calculate monthly R 0 as estimated by Mordecai et al. (Mordecai et al., 2017) (https://figshare.com/s/b79bc7537201e7b5603f). Doing so for 5,000 samples from the posterior of temperature-R 0 relationships and normalizing between 0 and 1 yielded a description of relative Ae. aegypti transmission potential per month in Havana, Cuba during 2014-2017. Aggregated monthly weather data for and model outputs are available at: https://github.com/andersenlab/paper_2018_cuba-travel-zika.