Detection of infectious agents in lungs of slaughtered pigs in association with cranioventral pulmonary consolidation

Introduction
Respiratory diseases have a substantial impact on swine production worldwide. Understanding the relationship between gross lung lesions and the presence of infectious agents is crucial for developing effective disease control strategies that target both primary and secondary pathogens.

Material and Methods
A cross-sectional study was conducted on 22 pig farms in western Poland. Cranioventral pulmonary consolidation (CVPC) in slaughtered pigs was assessed, and 20 lung tissue samples were collected from each herd. The presence of common bacterial and viral respiratory pathogens was identified using PCR-based methods.

Results
The disorder was observed in 79.3% (95% confidence interval 75.3–82.8) of slaughtered pigs across all examined herds. The most frequently detected pathogens at both the herd and individual animal levels were Glaesserella parasuis, Mycoplasma hyopneumoniae and porcine circovirus 2. Co-infections involving two or more respiratory pathogens were prevalent, occurring in 100% of herds and 87.7% of individual pigs. Mean CVPC scores were significantly higher in pigs infected with Mycoplasma hyopneumoniae, Mycoplasma hyorhinis and porcine reproductive and respiratory syndrome virus 1.

Conclusion
These findings highlight the multifactorial nature of respiratory infections in pigs. Effective control measures should consider the high prevalence of co-infections and their impact on lung lesion severity to improve overall herd health and productivity.