Synergism between Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Salmonella choleraesuis

Summary and Implications

This study was conducted to investigate the effects of exposure to porcine reproductive and respiratory syndrome virus, Salmonella choleraesuis, and stress on young swine. Five-week-old segregated early weaned pigs were randomly assigned to one of eight treatments consisting of all possible combinations of three factors: S. choleraesuis (SC) on day 0, porcine reproductive and respiratory syndrome virus (PRRSV) on day 3, and dexamethasone (DEX) on days 3 to 7. DEX was used as a proxy for stress. Treatment differences were seen in performance parameters, levels and duration of SC shedding, level and distribution of SC in tissues, clinical disease, and mortality. The results of this study provided evidence to support field observations that clinical outbreaks of PRRS are the result of interactions among concurrent infections and stressors.

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