1. Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia;
2. Atlanta Research and Education Foundation, Decatur, Georgia;
3. Office of Epidemiology and Research, Puerto Rico Department of Health, San Juan, Puerto Rico;
4. Epidemic Intelligence Service, Division of Scientific Education and Professional Development, Centers for Disease Control and Prevention, Atlanta, Georgia