Diagnosis of viral respiratory disease in swine

V iruses reported to cause respiratory disease in swine include swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV), porcine respiratory coronavirus (PRCV),porcine cytomegalovirus (PCMV),porcine paramyxovirus (PPMV), hemagglutinatingencephalomyelitisvirus (HEV), encephalomyocarditis virus (EMC), porcine parvovirus (PPV), porcine adenovirus, and porcine enterovirus.I-11 The first three viruses (SIV,PRRSV,PRY) are the viruses most likely to be involved in respiratory problems in field situations, and initial diagnostic efforts should be directed toward detecting these agents. Past studies in Europe and the United States and more recent reports from Canada suggest PRCV may be an emerging pathogen that should also be considered.12,13 Additional efforts to identify the other viruses are probably not warranted until the more common pathogens have been ruled out. In severe respiratory disease problems, multiple viruses may be involved. In our experience, the two viruses most frequently found concurrently in severe endemic nursery and grower pig pneumonia problems are SIVand PRRSv.European studies have identified concurrent PRCV,PRRSV,and SIVinfections.14,15