1. Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA
2. Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
3. Enteric Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
4. Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana, USA
5. Subunit Enteric Vaccines and Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA