FIG 5.

Spatiotemporal incidence of H3N2 CIV infection in the United States. Samples included those collected throughout the United States between March 2015, soon after the first introduction of virus, and September 2017. Blue marks indicate samples that were tested for CIV but were negative, while red marks indicate samples that tested positive for H3N2 CIV. Yellow bars on the incidence-by-date histogram (lower panel) indicate periods of elevated incidence. An animated version of this map is included in Movie S1 in the supplemental material.