Genomic epidemiology reveals multiple introductions of Zika virus into the United States.
Grubaugh ND., Ladner JT., Kraemer MUG., Dudas G., Tan AL., Gangavarapu K., Wiley MR., White S., Thézé J., Magnani DM., Prieto K., Reyes D., Bingham AM., Paul LM., Robles-Sikisaka R., Oliveira G., Pronty D., Barcellona CM., Metsky HC., Baniecki ML., Barnes KG., Chak B., Freije CA., Gladden-Young A., Gnirke A., Luo C., MacInnis B., Matranga CB., Park DJ., Qu J., Schaffner SF., Tomkins-Tinch C., West KL., Winnicki SM., Wohl S., Yozwiak NL., Quick J., Fauver JR., Khan K., Brent SE., Reiner RC., Lichtenberger PN., Ricciardi MJ., Bailey VK., Watkins DI., Cone MR., Kopp EW., Hogan KN., Cannons AC., Jean R., Monaghan AJ., Garry RF., Loman NJ., Faria NR., Porcelli MC., Vasquez C., Nagle ER., Cummings DAT., Stanek D., Rambaut A., Sanchez-Lockhart M., Sabeti PC., Gillis LD., Michael SF., Bedford T., Pybus OG., Isern S., Palacios G., Andersen KG.
Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.