1. Division of Pulmonary, Allergy, Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
2. Division of Comparative Pathology, Tulane National Primate Research Center, Covington, Louisiana, USA
3. Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
4. Department of Environment and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania, USA