1. Department of Fish and Wildlife Sciences and the Aquaculture Research InstituteUniversity of IdahoPost Office Box 441136MoscowIdaho83844‐1136USA
2. Present address: Oregon Department of Fish and Wildlife, Department of MicrobiologyOregon State UniversityNash Hall, Room 220. 97331‐3804CorvallisOregonUSA
3. Paul G. Allen School for Global Animal HealthWashington State UniversityPullmanWashington99164‐7090USA