1. Department of Animal Science; Michigan State University; East Lansing Michigan USA
2. Department of Pathobiology and Diagnostic Investigation; Michigan State University; East Lansing Michigan USA
3. Diagnostic Center for Population and Environmental Health; Michigan State University; Lansing Michigan USA
4. Ramboll Environ; Burton; Ohio USA
5. KERN Statistical Services; St. Cloud; Minnesota USA
6. Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health; State University of New York at Albany; Albany New York USA