Coronaviruslike particles in human gastrointestinal disease. Epidemiologic, clinical, and laboratory observations.

Coronaviruslike particles (CVLPs) were visualized by direct electron microscopy (EM) of diarrheal stools in 49 of 126 infants and children between 1 month and 12 years of age during a three-year observation period. The clinical and epidemiologic features of these patients were analyzed and compared with patients with diarrhea who were shedding rotaviruses, or whose stools were negative for enteric viruses by EM. Seasonal and age distributions for CVLP shedding were similar to those for rotaviruses (in most cases less than 1 year of age; peak months were September through January), as were the symptoms and median durations of illness. Prospective studies of three subsequent patients suggest that the duration of shedding in acute illness is five to at least 25 days. Multiple attempts to cultivate the CVLPs were unsuccessful. In addition, partial purification of CVLPs from stool specimens was performed, and immunologic analysis by immunoelectron microscopy and radial immunodiffusion showed no antigenic relatedness to prototype human (OC43 and 229E) or animal (bovine and canine) coronaviruses. These findings suggest that CVLPs may be an important cause of acute gastrointestinal illness in infancy, and may represent a virus antigenically unrelated to known human and animal coronaviruses.