Pathogenicity of concurrent infection of pigs with porcine respiratory coronavirus and swine influenza virus

Lanza, I; Brown, Ian H.; Paton, David

doi:10.1016/0034-5288(92)90131-k

Cited by 24 publications

(28 citation statements)

References 7 publications

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“…In experimental infections, virus replication has been demonstrated in nasal mucosa, tonsils, trachea, and lungs [72,86]. Low virus titres have occasionally been isolated from serum [23], but virus isolation from extra-respiratory sites was negative.…”

Section: Swine Influenza Virusmentioning

confidence: 99%

“…In studies with Belgian PRCV isolates, cells of the alveolar epithelia and septa were predominantly infected [35,36], while US isolates were shown to replicate mainly in bronchiolar epithelial cells [114]. Nasal virus excretion continues until 8-9 DPI [21,72,138,139] suggesting a similar duration of virus replication in the lungs. Virus neutralising antibodies in serum are detectable by 10-14 DPI [72,135].…”

Section: Porcine Respiratory Coronavirusmentioning

confidence: 99%

“…Nasal virus excretion continues until 8-9 DPI [21,72,138,139] suggesting a similar duration of virus replication in the lungs. Virus neutralising antibodies in serum are detectable by 10-14 DPI [72,135].…”

Section: Porcine Respiratory Coronavirusmentioning

confidence: 99%

“…Under strictly gnotobiotic circumstances, both European and US PRCV isolates fail to induce clinical disease, despite considerable lung pathology [35,50,92,148]. In some of the specific pathogen free (SPF) or conventional pig studies using pigs of various ages and various inoculation methods, mild dyspnoea and polypnoea and a short lasting fever [48,135,138] or fever without respiratory signs [21,40,72] have been observed. Slightly reduced weight gains have also been recorded.…”

Section: Porcine Respiratory Coronavirusmentioning

confidence: 99%

“…As for lung pathological lesions, the American PRCV isolates differ in their ability to induce clinical signs in conventional pigs and these differences might relate to different genome deletions [95]. To test the hypothesis that the severity of disease induced by PRCV depends on concurrent infection, experimental combined infections with PRCV followed by SIV [72,139], and with PRRSV followed by PRCV [141] were performed. The clinical effects of such dual virus infections were more severe than the single virus infections in some but not in all studies.…”

Section: Porcine Respiratory Coronavirusmentioning

confidence: 99%

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Proinflammatory cytokines and viral respiratory disease in pigs

2000

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-Swine influenza virus (SIV), porcine respiratory coronavirus (PRCV) and porcine reproductive and respiratory syndrome virus (PRRSV) are enzootic viruses causing pulmonary infections in pigs. The first part of this review concentrates on known clinical and pathogenetic features of these infections. SIV is a primary respiratory pathogen; PRCV and PRRSV, on the contrary, tend to cause subclinical infections if uncomplicated but they appear to be important contributors to multifactorial respiratory diseases. The exact mechanisms whereby these viruses cause symptoms and pathology, however, remain unresolved. Classical studies of pathogenesis have revealed different lung cell tropisms and replication kinetics for each of these viruses and they suggest the involvement of different lung inflammatory responses or mediators. The proinflammatory cytokines interferon-α (IFN-α), tumour necrosis factor-α (TNF-α) and interleukin-1 (IL-1) have been shown to play key roles in several respiratory disease conditions. The biological effects of these cytokines and their involvement in human viral respiratory disease are discussed in the second part of this review. The third part summarises studies that were recently undertaken in the authors' laboratory to investigate the relationship between respiratory disease in pigs and bioactive lung lavage levels of IFN-α, TNF-α and IL-1 during single and combined infections with the above viruses. In single SIV infections, typical signs of swine "flu" were tightly correlated with an excessive and coordinate production of the 3 cytokines examined. PRCV or PRRSV infections, in contrast, were subclinical and did not induce production of all 3 cytokines. Combined infections with these 2 subclinical respiratory viruses failed to potentiate disease or cytokine production. After combined inoculation with PRCV followed by bacterial lipopolysaccharide, both clinical respiratory disease and TNF-α/IL-1 production were markedly more severe than those associated with the respective single inoculations. Taken together, these data are the first to demonstrate that proinflammatory cytokines can be important mediators of viral respiratory diseases in pigs. respiratory coronavirus, PRCV), et le virus du syndrome dysgénésique et respiratoire porcin (porcine reproductive and respiratory syndrome virus, PRRSV) sont des virus enzootiques provoquant des infections pulmonaires chez le porc. Les caractéristiques cliniques et pathogénétiques de ces infections sont données dans la première partie de cette revue. Le SIV est un agent pathogène respiratoire primaire ; les PRCV et PRRSV, en revanche, ne causent que des infections subcliniques en l'absence de complications, mais ils contribuent de manière importante aux maladies respiratoires multifactorielles. Cependant, les mécanismes précis par lesquels ces virus provoquent des symptômes et une pathologie demeurent inconnus. Les études classiques de pathogenèse ont révélé un tropisme pour les cellules pulmonaires et des cinétiques de réplication différents pour...

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Section: Swine Influenza Virusmentioning

confidence: 99%