Submitted to: Journal of the American Veterinary Medical Association
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/27/2009
Publication Date: 7/1/2010
Publication URL: avmajournals.avma.org/doi/pdf/10.2460/javma.237.1.87
Citation: Moore, D.A., Kohrs, P., Baszler, T., Faux, C., Sathre, P., Wenz, J.R., Eldridge, L., Li, H. 2010. Outbreak of malignant catarrhal fever among cattle associated with a state livestock exhibition. Journal of the American Veterinary Medical Association. 237(1):87-92. Interpretive Summary: This report documented multiple cases of malignant catarrhal fever (MCF), a fatal disease caused by a herpesvirus, identified in a two week period in November 2008, in cattle owned by individuals in different geographic locations within the state of Washington. A total of 24 out of 132 head of cattle co-housed with domestic sheep in one barn at Washington's Puyallup fair died due to the disease. Outbreaks of MCF in cattle involving such a large number of animals are unusual, particularly those associated with livestock exhibitions. Although the exact factors triggering this outbreak have not been completely identified the recommendations have been made for livestock exhibitors to reduce the possibility of other outbreaks, including: 1) Sheep should be housed separately from cattle, 2) Cattle and sheep housing should be separated temporally, 3) People visiting between different groups of livestock should use a hand-sanitizer and footbath between barns, 4) Exhibitors should not haul sheep and cattle in the same trailer, and 5) Equipment should not be shared between animals at the fair.
Technical Abstract: Case description – Severe disease and death in cattle exhibited at a state fair and naturally infected with Ovine Herpesvirus 2 (OvHV-2). Clinical Findings – Most affected cattle had anorexia, depression, diarrhea, fever and respiratory distress ultimately leading to death. Average duration of clinical signs until death was five days (range 1-26). Average number of days between apparent exposure and death was 70 days (range 46–139). Treatment and Outcomes –Twenty-four of 132 head of cattle co-housed in one barn died due to malignant catarrhal fever (MCF). Samples from 19 cattle submitted for diagnosis were positive for OvHV-2 by PCR. Attack rates in different areas of the barn were associated with distance from the center of the barn but not distance from the center of the sheep pens. Clinical Relevance – Outbreaks of MCF in cattle are unusual, particularly those associated with livestock exhibitions. Because the clinical signs may be similar to some trans-boundary diseases, MCF cases should be reported and investigated. This outbreak provides evidence to suggest that fair boards and veterinarians reexamine biosecurity recommendations for livestock exhibitors. To reduce possibility of other outbreaks: 1) Sheep should be housed separately from cattle, 2) Cattle and sheep housing should be separated temporally, 3) People visiting between different groups of livestock should use a hand-sanitizer and footbath between barns, 4) Exhibitors should not haul sheep and cattle in the same trailer, and 5) Equipment should not be shared between animals at the fair.