Studies on the growth of feline panleukopaenia virus in cell cultures

The growth of feline panleukopaenia virus was examined in relation to various cell growth curves of secondary feline kidney cells. In cell cultures with a high mitotic index, the manifestation of virus infection, expressed as percentage number of cells with inclusion bodies, was correspondingly high. In cultures with low mitotic index, the percentage number of cells with inclusion bodies was low. A cytopathic effect was seen by inoculation of virus with a titre of 10-3-5TCID-50/ML. This effect was most pronounced using cell cultures seeded in a quantity of 1 million cells per ml to 500,000 cells per ml with inoculation made during the first 24 hours after seeding when the mitotic index was high. Both the cytopathic effect and the occurrence of inclusion bodies were of transient nature. The peak of infection, both with regard to the cytopathic effect and the percentage number of cells with inclusion bodies, was seen three days after inoculation.