Isolation of coronaviruses from neonatal calf diarrhoea in Great Britain and Denmark

Coronaviruses were isolated from neonatal calves with diarrhoea in Great Britain and Denmark. They were serially passed in gnotobiotic calves which developed acute diarrhoea. Pathological lesions were found in the small and large intestines. Coronaviruses were demonstrated by electron microscopic examination of the faeces and intestinal contents, immunofluorescent staining of sections of small and large intestine and by isolation in tracheal organ cultures. In early passages of the British coronavirus, particles of about 30 nm in diameter were observed in the faeces by electron microscopy. These particles were removed from the coronavirus preparations by cross-protection experiments in calves. The coronaviruses were morphologically and antigenically similar to the bovine coronavirus isolated in the United States and the British virus was adapted to replicate in calf kidney cell cultures.