1. Division of Infectious Diseases, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
2. Division of Infectious Diseases, Department of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
3. Department of Ophthalmology, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
4. Hospital Infantil de México, Federico Gómez, México City, México
5. Palo Alto Medical Foundation Toxoplasma Serology Laboratory, National Reference Center for the Study and Diagnosis of Toxoplasmosis, Palo Alto, California
6. Division of Infectious Diseases, Stanford University, Stanford, California