Purification, morphology and partial characterization of a reovirus-like agent associated with neonatal calf diarrhea

Abstract

Studies have been conducted on a virus which has recently been implicated as an etiological agent in widely disseminated cases of calf diarrhea. The virus was isolated from feces and intestinal mucosa from experimentally infected calves and from cell cultures which had been inoculated with material from infected calves. The virus was purified by differential centrifugation, nuclease treatment, extraction with Genetron 113 and cesium chloride (CsC1) gradient. Purified and non-purified samples were studied by electron microscopy. Both types of preparations contained unenveloped particles approximately 64 nm in diameter with a hexagonal core region 36 nm in diameter. Subunits of the capsids appeared to be arranged in accordance with cubic synmetry. Essential lipids were not associated with the virus. The buoyant density of purified virus was 1.359. Viral nucleic acid was determined by chemical methods to be ribonucleic acid (RNA). The morphology and some chemical characteristics appear to be similar to those of the reovirus group. However, the exact classification of this virus and its relationship to other groups remains to be established.