Pathogenesis of a bovine enterovirus-1 isolate in experimentally infected calves.

The pathogenesis and virulence of Bovine enterovirus-1 (BEV-1) in cattle is largely unknown. Reports concerning its virulence suggest that there might be an association between BEV-1 infections and a range of diseases in cattle that vary from respiratory to enteric to reproductive disease and infertility. In the current study, the pathogenesis associated with acute infection of BEV-1 in calves experimentally inoculated with the Oklahoma isolate of BEV-1 was described. Although interpretation of the study was limited by lack of an effective control group, results suggest that an association between inoculation of BEV-1, virus localization, and the potential development of lesions in the brain and heart probably exists. In the experiment, BEV-1 virus localized to the terminal ileum, ileocecal and cecocolonic junctions, spiral colon, and ileocecal lymph nodes; BEV-1 virus was detected in the cytoplasm of enterocytes, lamina propria macrophages, endothelium, neurons of the submucosal and myenteric plexi, and lymphocytes of the submucosal lymphoid tissue. Although no clinical signs were noted following acute infection, BEV-1 was localized in the cerebellar white matter of a calf with encephalitis and in the heart of another calf with coronary arteritis. The current study suggests that the BEV-1 isolate is infectious to young calves and that BEV-1 potentially can have a similar pathogenesis to that observed in natural or experimental enterovirus infections in other species.