Enzootic pneumonia in feeder pigs: Association with transmissible gastroenteritis virus infection.

Infection with transmissible gastroenteritis virus (TGEV) was present in some pigs on arrival at a feeder pig farm and was well established three weeks later. TGE infection preceded Mycoplasma hyopneumoniae infection, which was not detected until three weeks after arrival. Severe lesions of enzootic pneumonia were observed at the end of the fattening period.A trial was subsequently done in six-week-old-pigs in order to evaluate the potentiating effect of TGEV infection on experimental M. hyopneumoniae infection. The effects of mycoplasmal infection were aggravated when associated with TGEV infection as determined by the extent of pneumonic lesions observed two weeks later.