1. Division of Infectious Diseases, Washington University in St Louis , St Louis, Missouri , USA
2. Division of Pediatric Infectious Diseases, Le Bonheur Children’s Hospital , Memphis, Tennessee , USA
3. Division of Infectious Diseases, University of Maryland , Baltimore, Maryland , USA
4. Division of Infectious Diseases, University of Kansas , Kansas City, Kansas , USA
5. Division of Infectious Diseases, University of Iowa , Iowa City, Iowa , USA
6. Emerging Infections Network, University of Iowa , Iowa City, Iowa , USA
7. Division of Infectious Diseases, University of Alabama , Birmingham, Alabama , USA