Abstract
A number of feline coronavi rus isolates have been characterized over the last few years. These isolates consist of what we have referred to as feline enteric coronavi ruses (FECVs) and feline infectious peritonitis viruses (FIPVs). FECVs cause a transient enteritis in kittens but no systemic illness. FIPVs, in contrast, cause a systemic and usually fatal disease syndrome characterized either by an exudative serositis or a disseminated granulomatous disease. Although the diseases they cause are quite different, FECVs and FIPVs are antigenically and morphologically indistinguishable from each other. FECVs have a strict tropism for mature intestinal epithelial cells and do not appear to replicate in macrophages. In contrast, FIPVs, appear to spread rapidly from the intestinal mucosa and replicate in macrophages.