Immune electron microscopy of transmissible gastroenteritis virus and rotavirus (reovirus-like agent) of swine.

Immune electron microscopy (IEM) was developed as a diagnostic aid for detecting and identifying transmissible gastroenteritis virus and rotavirus (reovirus-like agent) in fecal and intestinal contents from cases of gastroenteritis in young pigs. Variables involved in use of direct IEM and its sensitivity were determined. Aggregates of virus coated with specific antibody were seen in virus samples mixed with homologous convalescent antiserum, but not in control samples containing preexposure serum or antibody directed against a heterologous virus. At least a ten fold enhancement of the sensitivity of direct IEM for virus detection was accomplished using indirect IEM employing rabbit anti-porcine IgG to further aggregate virus-antibody complexes. The technique was used to investigate the size and morphology of the porcine rotavirus. Particles ranged from 55 to 70 nm in diameter and had capsomere structures. Morphologically, the porcine rotavirus resembled the calf and human rotaviruses. By IEM, employing specific antiserums for each virus, porcine rotavirus was found to be antigenically related to these 2 viruses, but not to the reovirus type 3.