SEROLOGICAL EVIDENCE FOR PNEUMOVIRUS INFECTIONS IN PIGS

A serological survey was carried out on pig sera from herds in Norther n Ireland to investigate the incidence of reactivity to bovine respira tory syncytial virus (BRSV) antigens, A total of 529 pig sera from 61 herds were tested and 219 (41 per cent) were found to be reactive with BRSV-infected cell cultures in an indirect inmunofluorescence test, N one of the BRSV-renctive sera immunostained turkey rhinotracheitis vir us-infected cell cultures, indicating specificity for BRSV epitopes, T he specificity of this reactivity for BRSV antigen was confirmed by do uble immunolabelling, using monoclonal antibodies to BRSV and two pig sera with different reactivities to BRSV antigens, A longitudinal sero logical investigation of two litters of pigs indicated that BRSV-serum reactivity developed between six and 11 weeks after birth, The immuno fluorescent staining pattern observed with the majority (73 per cent) of the BRSV-reactive pig sera was typical of that observed with known BRSV-reactive bovine sera, The other immunoreactive pig sera stained B RSV-infected cell cultures in an atypical staining pattern, These diff erent reactivity patterns, combined with the results of the serum neut ralisation tests, suggest that more than one serotype of a porcine pne umovirus may exist.