Clinical disease associated with epizootic hemorrhagic disease virus in cattle in Illinois

Objective—To describe the clinical manifestation of epizootic hemorrhagic disease virus (EHDV) in cattle during an outbreak in northwestern Illinois in the fall of 2013. Design—Outbreak survey. Sample—18 EHDV-affected cattle herds. Procedures—Herds with confirmed EHDV-infected cattle were selected for the survey on the basis of having a manager willing to participate. A survey was developed and administered to obtain information regarding the demographics of EHDV-affected herds and the clinical signs and outcomes for EHDV-infected cattle. Results—The managers of 13 beef and 5 dairy herds participated in the survey. The herds contained approximately 1,400 cattle, of which 61 were infected with EHDV and 16 died. Most cattle clinically affected with EHDV were adults, although 1 herd had 6 calves with clinical signs, and EHDV was identified during postmortem testing of 1 of those calves. Clinical signs most commonly observed were oral ulcerations or erosions, anorexia, weight loss, and lameness that typically lasted > 7 days. Of the 18 herds, 17 had wooded areas and 14 had at least 1 pond or marsh on the property. Deer were observed on the property of all farms. The EHDV outbreak in cattle coincided with an EHDV outbreak in deer in the region. Conclusions and Clinical Relevance—This large-scale outbreak of EHDV in US cattle was unusual because calves were affected. Because there is no way to effectively predict or prevent an EHDV outbreak in cattle, development of a vaccine for use in cattle during an outbreak would be beneficial.