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

We found that the last local case from the Caribbean was also reported in August, 2017. However, we observed a spike in Zika cases from travelers returning from the Caribbean during the summer of 2017 that were not captured by local reports, and Zika virus infected travelers from the Caribbean were reported until the end of the reporting period from the ECDC (December, 2017) and FL-DOH (October, 2018; Fig. 1A ). By examining potential source locations for the travelassociated Zika cases in 2017, we found that between June, 2017 and October, 2018 more than 98% of them came from Cuba (90 of 91 Zika diagnoses in Florida, 63 of 64 Zika diagnoses in Europe; Fig. 1B ). To further confirm the timing of a Zika outbreak in Cuba, we obtained travel-related infection data from the GeoSentinel Surveillance Network (Hamer et al., 2017; Leder et al., 2017) and found that 76% of the Zika cases associated with travel from Cuba were diagnosed in 2017 (22 of 29; Fig. 1C ). While our travel data show that a Zika outbreak peaked in Cuba in 2017 with waning transmission continuing into 2018, during this time period no local Zika cases were reported by Cuba to PAHO or other international public health agencies (PAHO, 2017a).