An uncommon clinical form of foot-and-mouth disease in beef cattle presented with cornual skin lesions.

Foot-and-mouth disease (FMD) is a major infectious disease in livestock. The common clinical signs in cattle include epidermal vesicles that are majorly distributed around oronasal cavity, feet and teats. The aim of this report is to document an uncommon clinical form of the disease which comprises the occurrence of classic vesicular lesion in a rarely observed location of the horn vegetative tissue. During Iran's outbreak of FMD in 2013, field investigation, clinical examination and sampling from the affected herds in Qom province were performed. Specimens of mouth epithelium and horn vegetative tissue were collected for virology and histopathologic study. All the samples collected from horns were positive for foot-and-mouth disease virus (FMDV) in both enzyme linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) tests, and the strain of the virus was identified as A05. Surprisingly, all the animals with horn lesion came from beef herds, were less than 12 months old and had more severe signs of the systemic disease. Since the same strain of virus did not cause similar lesions in surrounding dairy cows, it was concluded that occurrence of horn lesions may be more associated with host factors rather than virus strain.