The effect of immunosuppression with cyclophosphamide on an experimental porcine enterovirus infection in piglets.

Eleven specific pathogen-free, five week old piglets were infected orally with the T80 strain of porcine enterovirus type 2. Three days after infection, five of the piglets were treated with cyclophosphamide, together with two of four uninfected control piglets. The treated, infected piglets developed severe diarrhea, and one showed signs of encephalomyelitis. These piglets showed no virological evidence of recovery from the infection, since the virus persisted throughout the intestinal tract, and they failed to mount a serological response. It was concluded that immunosuppression with cyclophosphamide impaired the normal recovery mechanisms in this infection, providing further evidence that the humoral immune response is an important defence mechanism against porcine enterovirus infection in piglets.