1. Centers for Disease Control and Prevention, Office of Readiness and Response, U.S. National Authority for Containment of Poliovirus, Atlanta, GA 30329, USA
2. Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Atlanta, GA 30329, USA
3. Centers for Disease Control and Prevention, Office of Laboratory Science and Safety, Atlanta, GA 30329, USA
4. Morehouse School of Medicine, Atlanta, GA 30310, USA