Abstract
Six piglets with cutaneous lesions were born on a farm in Kagoshima Prefecture, Japan. The lesions manifested as papules and pustules over the entire body of each piglet. A pathological and virological analysis was performed on 5 of the affected piglets. Piglets with large multiple cutaneous lesions also showed tongue erosions. We observed hyperplasia, ballooning degeneration, eosinophilic cytoplasmic inclusions, and intranuclear vacuoles in the prickle cells of the skin and tongues of the piglets. Upon performing immunohistochemistry and electron microscopy, swinepox virus antigens and poxvirus particles were detected, respectively, in the lesions. Moreover, a polymerase chain reaction helped detect an identical sequence in the gene encoding the swinepox virus envelope protein in 2 piglets; this sequence was closely related genetically to that observed in viruses previously isolated from the United States. Based on these results, the disease was concluded to be congenital swinepox. To the best of our knowledge, this is the first report on a genetic comparison of swinepox virus in Japan.
