[1] Univ N Carolina, Dept Epidemiol, Chapel Hill, NC USA
[2] NIAID, Infect Dis Lab, NIH, Bethesda, MD 20892 USA
[3] Univ N Carolina, Dept Microbiol & Immunol, Chapel Hill, NC USA
[4] Univ N Carolina, Dept Anat Pathol & Surg Pathol, Chapel Hill, NC USA
[5] NIAID, Comparat Med Branch, NIH, Bethesda, MD 20892 USA
[6] NIAID, Immunopathol Lab, NIH, Bethesda, MD 20892 USA