This report describes five cases of naturally occurring feline coronav
irus enteritis. The affected animals, aged 2 months to 7 years, had a
clinical history of intestinal symptoms, including diarrhoea or vomiti
ng, or both. They exhibited variable histological changes in the epith
elium of the small intestine, ranging from degeneration of single cell
s and detachment of groups of cells from the villous tips to regenerat
ive processes of the crypt epithelia. Post-mortem diagnosis was based
on the immunohistochemical demonstration of coronavirus antigen within
intestinal epithelial cells and on the electron microscopical demonst
ration of coronavirus particles in the faeces. In addition, one animal
was immunohistochemically positive for antigens of feline leukaemia v
irus (FeLV) and exhibited intestinal changes consistent with FeLV-asso
ciated enteritis. Two cats were tested serologically for feline immuno
deficiency antibodies, with negative results. The findings indicate ch
at natural coronavirus infection is a potential cause of severe enteri
tis in juvenile and adult cats. (C) 1998 W.B. Saunders Company Limited
.