Gastrointestinal and skin lesions in piglets naturally infected with pseudorabies virus.

Pseudorabies virus (PRV) infection was diagnosed in 4 piglets from a litter by immunohistopathologic examination and virus isolation. Three piglets had moderate to severe neuronal degeneration, and PRV antigen was detected in Auerbach's myenteric plexus and Meissner's submucosal plexus of the gastrointestinal tract. One piglet had 2 types of skin lesions. One lesion appeared on the hip and ear and was characterized by ballooning degeneration, necrosis of epithelial cells, and intranuclear inclusion bodies. The other was found on the ear and hematoma-like lesion was composed of fibrinoid exudation and degenerative connective tissue. PRV antigen was clearly demonstrated in both skin lesions. These results suggested that degeneration of myenteric plexuses might be another characteristic of lesions in PRV-infected pigs and that the virus spreads by interaction between the skin and myenteric plexuses to the central nervous system.

Isolation of ovine rotavirus in cell cultures. Brief report.

Three cytopathic rotavirus strains were isolated in MA 104 cells from intestinal contents of lambs with diarrhea. Pretreatment of virus with pancreatin and incorporation of a small amount of pancreatin in maintenance medium were important for establishment of the strains in these cells. The isolates showed marked cross reactions with bovine rotavirus in immunofluorescence, but no cross reaction with bovine, human, simian, equine, porcine and lapine rotaviruses in neutralization.

Micro method for performing titration and neutralization test of hog cholera virus using established porcine kidney cell strain.

Hog cholera (HC) virus and antibody against it were estimated by the END method with microplates and CPK porcine kidney cell strain. To establish the technique of this method, studies were made on such basic conditions of the method as the type of strain of Newcastle disease virus (NDV), the time of challenge with this virus, and the concentration of serum in culture fluid. There was little difference in the infective titer of HC virus estimated between the END method performed by the established technique and the same method by the conventional technique with test tubes and swine testicle (ST) cells. Besides, there was a high correlation between the neutralizing antibody titer measured by the one technique and that measured by the other. The coefficient of correlation was r = +0.948 in this case. From the experimental results mentioned above it was concluded that the END method by the micro-technique with CPK cells was simpler than and as reliable as the same method conducted by any conventional technique, and that it was a practicable one capable of testing many samples.