1. From the Departments of Medical Ultrasonics (T.Z., J.Z., J.J., Z.H., M.W., R.Z.) and Infectious Disease (G.Z.), Third Affiliated Hospital of Sun Yat-Sen University, 600 TianHe Rd, Guangzhou 510630, China; and Department of Environmental Health Sciences, University at Albany, State University of New York, Rensselaer, NY (X.D.).