Abstract
Selected tissues from 13 germfree and 3 specific pathogen-free cats experimentally infected with feline infectious enteritis were studied electron microscopically. Intestinal lesions consisting of dilatation of intercellular spaces and of endoplasmic reticular cisternae occurred only in specific pathogen-free cats. No lesion was demonstrated in the intestine of infected germfree cats, indicating that the virus of feline infectious enteritis may not be solely responsible for the intestinal lesions described in the naturally occurring disease. The lesions in the lymph nodes were identical in specific pathogen-free and germfree cats and consisted of lymphocytic destruction within 72 hours post-inoculation and reactive proliferation of reticular cell-macrophages and plasma cells. The preferred designation of this disease in cats as feline infectious panleukopenia is supported.