Gammaherpesviruses and pulmonary fibrosis: evidence from humans, horses, and rodents.
Authors: Williams K J
Journal: Veterinary pathology
Summary
# Gammaherpesviruses and pulmonary fibrosis: A cross-species perspective Progressive pulmonary fibrosis represents a significant clinical challenge across species, particularly in humans (idiopathic pulmonary fibrosis) and horses (equine multinodular pulmonary fibrosis), yet aetiological factors remain largely elusive. Williams' review synthesises evidence from human medicine, veterinary practice, and experimental rodent models to examine the emerging hypothesis that gammaherpesviruses—specifically Epstein-Barr virus in humans and equine herpesvirus 5 (EHV-5) in horses—may trigger aberrant wound-healing responses and contribute to pathological lung fibrosis. The contemporary understanding of pulmonary fibrosis as a manifestation of abnormal epithelial repair, rather than simple inflammation, provides a mechanistic framework for understanding how viral epithelial injury might initiate or perpetuate fibrotic cascades. Experimental infection studies in mice using murine herpesvirus demonstrate that host and viral factors significantly influence whether infection progresses to lung fibrosis, offering translatable insights into the variable clinical presentations observed in naturally infected horses and humans. For equine practitioners, these findings support investigation of EHV-5 status in cases of progressive respiratory disease and suggest that viral management alongside anti-fibrotic strategies may warrant consideration, whilst the cross-species evidence indicates that pulmonary fibrosis should be reconceptualised as a potential long-term sequela of herpesviral infection rather than an exclusively degenerative process.
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Practical Takeaways
- •Consider viral infection, particularly equine herpesvirus 5, as a potential underlying cause in horses presenting with progressive lung fibrosis signs (chronic cough, exercise intolerance, respiratory distress)
- •Understanding that pulmonary fibrosis may result from abnormal healing after respiratory epithelial damage may guide treatment strategies toward managing the underlying injury process rather than just fibrosis symptoms
- •Monitor horses recovered from herpesvirus respiratory infections for signs of developing pulmonary fibrosis, as chronic sequelae may emerge through aberrant wound repair mechanisms
Key Findings
- •Gammaherpesviruses, particularly Epstein-Barr virus in humans and equine herpesvirus 5 in horses, are associated with progressive pulmonary fibrosis development
- •Pulmonary fibrosis across species appears to result from abnormal wound repair mechanisms in response to epithelial injury
- •Viral-induced epithelial injury is proposed as a significant pathogenic mechanism contributing to progressive lung fibrosis in both human and equine patients
- •Experimental evidence from murine herpesvirus models demonstrates that host and viral factors interact to determine the development of lung fibrosis