Historic Travel of H7N9 HA Gene (IMAGE) University of North Carolina at Charlotte Caption This image shows traffic of the HA segment of H7N9 influenza within China, Taiwan and Hong Kong, 2013–2014. Larger and darker nodes are hubs involved in the most shortest paths between places. Small white nodes are relatively isolated. The size of the arrowheads indicates the frequency and directionality of transmission. Credit Daniel Janies Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.