Outbreaks of bovine herpesvirus 2 infections in calves causing ear and facial skin lesions.

We describe 3 outbreaks of superficial dermatitis caused by bovine herpesvirus 2 (BoHV-2) in dairy breed calves. Clinically, all of the affected calves were 12-26 d of age, had alopecia and crusts on the face and ears, and were non-pruritic and afebrile. Affected animals recovered spontaneously without any treatment within 2-4 wk after onset of clinical signs based on 1 herd with follow up. Histologic examination of all skin crust or tissue samples identified neutrophilic inflammation, mild hyperkeratosis, multinucleate syncytial cells, and intranuclear inclusion bodies in the syncytial cells. Real-time PCR testing on affected surface crusts or tissue provided evidence of BoHV-2, and testing, where performed, was negative for parapoxvirus including bovine papular stomatitis virus and the ovine form of malignant catarrhal fever tested in EDTA blood samples. Bovine viral diarrhea virus also was negative by ELISA, as well as bovine herpesvirus 1 by immunohistochemistry. Direct electron microscopy of infected tissues in the first outbreak revealed herpesvirus-like particles.