Isolation of rhinovirus from cattle in outbreaks of acute respiratory disease

Summary

Twenty-four strains of a rhinovirus were isolated in primary cultures of calf kidney cells from affected cattle in two outbreaks of acute respiratory disease in Japan. These strains produced cytopathic effect resembling that produced by enteroviruses in calf kidney cell cultures. They were indistinguishable from one another by neutralization tests, indicating that they are strains of one and the same virus. The virus was serologically distinct from the English strain EC11 of bovine rhinovirus but similar to the German Sd-1 or English RS3×strain. The isolated virus replicated better at 30° or 33° C than at 37° C and best in a medium of pH 6.8 or 7.2 than at lower or higher pH; the degree of cytopathic effect reflected that of viral growth. Viral replication was inhibited by 5-iodo-2′-deoxyuridine, indicating the viral nucleic acid to be RNA. The virus was ether- and chloroform-resistant, and readily filtered through Sartorius membranes of 50 run pore size. The virus was readily inactivated by trypsin, and proved to be heatand acid labile. The virus was not stabilized by 1m MgCl₂ at heating of 50° C for 60 minutes. These properties are consistent with those established for rhinoviruses. The etiological significance of the isolated virus in the bovine disease remains to be investigated.