Abstract
During a period from late 1982 to early 1983, outbreaks of acute diarrhea were observed in swine of all ages throughout Japan. Transmissible gastroenteritis virus and rotavirus were ruled out as the cause by the immunofluorescent and serological examinations performed on specimens from two infected piglets obtained from two farms. The disease was reproduced, and the causative agent was passaged in piglets by oral inoculation with a trypsin-treated emulsion prepared from the small intestine of infected piglets. Numerous coronavirus-like particles were demonstrated by electron microscopy in negatively stained preparations of feces and intestinal contents, as well as in thin sections of the small intestinal mucous membrane from infected animals. Based on the data collected, it was concluded that the present cases should be diagnosed as porcine epidemic diarrhea caused by a coronavirus different from transmissible gastroenteritis virus.
