Cultivation and study of the properties of the Perego strain of the sheep poxvirus on heterologous tissue

: Strain Perego of the sheep pox virus, after 11 passages in lamb testis cultures, was successfully adapted and cultivated in 10 successive passages in a heterologous tissue--secondary cultures of newborn calf kidney. The infected cultures produced a cytopathic effect similar to that observed in a homologous culture, the difference being that part of the degenerated cells came off from the wall of the flask. At the level of its 10th passage the virus exhibited a titer of 10(3)CPE50. The virus was tested for harmlessness on sheep through a subcutaneous inoculation at a dose of 1 cm3 of a 1:10 dilution, and its testing for activity (1:100 dilution) caused an easily tolerated local reaction with a slight rise in the body temperature, the general status of the test animals remaining unaffected.