1. Gorgas Memorial Institute for Health Studies, Panama City, Panama;University of Panama, Panama City, Panama;
2. Centers for Disease Control and Prevention, Atlanta, Georgia, USA;
3. Gorgas Memorial Institute for Health Studies, Panama City, Panama;
4. University of Wisconsin, Madison, Wisconsin, USA;
5. University of New Mexico, Albuquerque, New Mexico, USA;
6. Ministry of Health, Panama City, Panama;
7. Complejo Hospital A.A.M., Panama City, Panama;
8. Pan American Health Organization, Washington DC, USA;
9. University of Texas, Galveston, Texas, USA