A recent study conducted by the Iowa State University Veterinary Diagnostic Laboratory (ISU VDL) is shedding light on the emergence of lung lesions in pigs resembling Atypical Interstitial Pneumonia (AIP).
Over the past several years, diagnosticians at ISU have observed cases of diffuse alveolar damage (DAD) in swine lungs — a lesion pattern that raised questions about whether the condition represents an emerging disease syndrome or a manifestation of known viral infections.
The investigation was funded by the Swine Health Information Center (SHIC).
Study Overview
According to SHIC Associate Director Dr. Lisa Becton, 42 cases met the diagnostic criteria for inclusion in the study.
Researchers performed PCR testing to detect common swine respiratory viruses, including:
-
Porcine Reproductive and Respiratory Syndrome (PRRS)
-
Swine Influenza Virus
-
Porcine Circovirus Type 2 (PCV2)
-
Parvovirus
Virus Detection Results:
-
PRRS detected in 71% of cases
-
Influenza detected in nearly 36%
-
PCV2 detected in approximately 17%
-
Parvovirus detected in about 45%
In several cases, two or even three viruses were detected simultaneously.
However, despite these findings, none of the viruses were definitively linked as the direct cause of the diffuse alveolar damage lesions.
Why This Matters for Producers
Dr. Becton emphasized that characterizing emerging syndromes is critical for the industry.
When new lesion patterns or disease presentations appear, veterinarians and producers must determine whether they are:
-
An expression of routine viral pathogens
-
A result of enhanced virulence
-
Or evidence of a new or emerging syndrome
Understanding that distinction helps guide mitigation strategies and biosecurity planning.
Protecting Respiratory Health
Although no single virus was identified as the direct cause of the DAD lesions, the study reinforces the importance of maintaining strong respiratory health programs, including:
-
Robust PRRS control strategies
-
Influenza vaccination programs
-
PCV2 vaccination protocols
-
Ongoing diagnostic surveillance
As Dr. Becton noted, even if the syndrome is not linked to a new pathogen, managing endemic viruses remains critical to reducing respiratory challenges.
Looking Ahead
This study provides valuable insight for:
-
Swine producers
-
Herd veterinarians
-
Diagnostic laboratories
As emerging patterns are identified, continued surveillance and collaborative research will remain essential to protecting herd health and production performance.
Details of the study are available through SHIC’s January eNewsletter at swinehealth.org.
