1 Bureau of Epidemiology, Pennsylvania Department of Health, Harrisburg, PA, USA.
2 Allegheny County Health Department, Pittsburgh, PA, USA.
3 Bureau of Laboratories, Pennsylvania Department of Health, Exton, PA, USA.
4 Allegheny Health Network, Pittsburgh, PA, USA.
5 Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.