| characterisation of a recent virulent transmissible gastroenteritis virus from britain with a deleted orf 3a. | analyses of transmissible gastroenteritis virus (tgev) and porcine respiratory coronavirus (prcv) isolates have suggested that tropism and pathogenicity are influenced by the spike protein and orf 3. in general, enteric viruses (tgev) have been shown to contain intact spike and orf 3 genes, whilst respiratory isolates (prcv) have major deletions within both regions. virulence has been correlated to a functional orf 3. here, sequence analysis of a recent isolate of virulent tgev, revealed a varia ... | 1999 | 10365166 |