1. Baylor College of Medicine, Department of Pediatrics, Section of Tropical Medicine, National School of Tropical Medicine, Houston, Texas.
2. The University of Texas Health Science Center at Houston, Center for Infectious Diseases, School of Public Health, Houston, Texas.
3. The University of Texas Medical Branch, Galveston, Texas.
4. City of Houston Department of Health and Human Services, Houston, Texas.
5. Harris County Public Health and Environmental Services, Houston, TX