1. Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
2. Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
3. Department of Civil Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
4. Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA