No abstract

An emerging swine disease principally involving periweaning piglets was examined. The disease was clinically characterized by lethargy, fever, emaciation, coughing, and severe abdominal breathing, hence colloquially named "Heko-heko" disease. The consistent lesions in affected piglets were diffuse interstitial pneumonia with pronounced type II pneumocytic proliferation, meningoencephalitis, and regression of the lymphoid tissues. The causal virus was isolated in primary porcine lung cell (PLC) cultures from various organs of affected piglets and showed serological relatedness to the European porcine reproductive and respiratory syndrome (PRRS) virus. Numerous virus particles, measured about 49 nm in diameter, were detected in the cytoplasm of alveolar epithelial cells and pulmonary macrophages in PLC cultures infected with the isolate. The condition could be experimentally reproduced in conventional piglets by intranasal inoculation with the isolate and the virus was reisolated from the infected animals.

Two cytopathogenic bovine rotavirus strains were isolated. The infectivity of both isolates was relatively stable at pH 3.0 and resistant to ether. Their replication was not affected by 5-iodo-2'-deoxyuridine. The new isolates shared immunofluorescent antigen with the Lincoln strain of bovine rotavirus. By neutralization test, however, these strains were clearly distinguished from one another.

No 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.