Abstract
From August to September, 1984, an epidemic of swinepox occurred in a certain region of Okayama Prefecture, where approximately 20 swine farms exist. All pig breeds were affected by swinepox at a rate of 24.3%.
Clinical symptoms included skin rashes which disappeared after one month. Hyperplasia of the stratum spinosum, intranuclear vacuoles and eosinophilic cytoplasmic inclusions were revealedhistopathologically.
After 5 or 6 blind passages in PK-15 cells, viral agents which caused CPE (i. e. rounding of infected cells) were isolated. The isolated virus was susceptible to ether, pH of 3.0 or heat treatment at 56°C for 30 min. Also, the viral nucleic acid was revealed to be DNA. Fowl, rabbits, mice and chorioallantoic membranes of embryonated chicken eggs were refractory to infection with the virus. In infected cells virus particles with the characteristic morphology of poxvirus were detected electron microscopically. Also, striated lamellar structures characteristic of swinepox virus infection were observed in both the cytoplasm and nucleus. When the virus was inoculated into the skin of piglets by the multiple-puncture method, pocks were produced only at the immediate area of inoculation.
