Pulmonary dysfunction was evaluated in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV, isolate VR-2332) and compared to clinical and pathological findings. Infected pigs developed fever, reduced appetite, respiratory distress and dullness at 9. days post-inoculation (dpi). Non-invasive pulmonary function tests using impulse oscillometry and rebreathing of test gases (He, CO) revealed peripheral airway obstruction, reduced lung compliance and reduced lung CO-transfer factor. PRRSV-induced pulmonary dysfunction was most marked at 9-18 dpi and was accompanied by a significantly increased respiratory rate and decreased tidal volume. Expiration was affected more than inspiration. On histopathological examination, multifocal areas of interstitial pneumonia (more severe and extensive at 10 dpi than 21 dpi) were identified as a possible structural basis for reduced lung compliance and gas exchange disturbances.
Bibliographical noteFunding Information:
The authors are very grateful to Annelie Langenberg, Sylke Stahlberg, Ines Lemser and to all colleagues working in the team of the animal house (FLI Jena, Germany) for their skilful assistance during the study. Furthermore, the authors are thankful to colleagues of the Institute of Bacterial Infections and Zoonoses (IBIZ) in the ‘Friedrich-Loeffler-Institut’ (Jena, Germany), namely Dr. Ulrich Methner and his team for Salmonella spp. diagnosis and Dr. Astrid Raßbach and co-workers for performing bacterial screening for Pasteurella spp., Bordetella spp., Haemophilus spp. and APP. In addition, the authors thank Dr. Konrad Sachse and staff of the OIE Reference Laboratory for Chlamydiosis for Chlamydia spp. testing and Renate Haß for assaying Mycoplasma spp. This work was funded by the non-profit organisation ‘Akademie für Tiergesundheit e.V.’ (Germany), which provided a scholarship for Judith Wagner.
- Porcine reproductive and respiratory syndrome virus
- Pulmonary function testing