Equine sarcoids from Southern Italy: Molecular and Histopathological characterization.

Equine sarcoids and other skin lesions from Southern Italy were studied to investigate the presence and characteristics of bovine papillomaviruses (BPVs), revealing frequent BPV infections and their histopathological features.

Background and Objectives

• Equine sarcoids are common skin tumors in horses, often linked to bovine papillomaviruses (BPVs), particularly δ types.
• The study aimed to detect the presence of four specific δ BPV genotypes (BPV-1, BPV-2, BPV-13, BPV-14) in equine skin lesions from Southern Italy.
• It also sought to characterize the histopathological features of these lesions and explore any associations between BPV types and tissue changes.

Methods

• A total of 63 equine skin samples were collected, including sarcoid tumors as well as non-sarcoid tumors and non-neoplastic skin conditions.
• Polymerase chain reaction (PCR) and DNA sequencing techniques were applied to detect and genotype BPV DNA in the tissue samples.
• Histopathological examination evaluated the microscopic features of each lesion, focusing on fibroblastic atypia (abnormal fibroblast appearance) and extracellular matrix deposition (the accumulation of supportive tissue material).

Results

• BPV DNA was found in approximately 70% (69.84%) of the samples, indicating a high prevalence of infection.
• Among the detected BPVs, BPV-1 and BPV-2 were the most common genotypes identified, followed by BPV-13; BPV-14 was not found in any sample.
• Notably, BPV DNA was present not only in sarcoid tumors but also in other non-sarcoid tumors and non-neoplastic lesions, suggesting a broader involvement of BPVs in equine skin pathologies.
• Histopathology revealed that 41 samples exhibited classical sarcoid features, including:
• Fibroblastic atypia – irregular and abnormal fibroblast cells.
• Increased extracellular matrix deposition – excessive buildup of connective tissue substances.
• Although no statistically significant correlation was found between specific BPV genotypes and the histopathological features overall, infection with BPV-1 tended to associate with a more severe degree of fibroblastic atypia and more abundant extracellular matrix, indicating a potentially stronger pathogenic role.

Conclusions and Implications

• This study underscores the high prevalence of δ BPVs, especially BPV-1 and BPV-2, in equine sarcoids from Southern Italy.
• It highlights the complex tissue changes characteristic of sarcoids and suggests that different BPV genotypes may influence the severity of histological alterations.
• The detection of BPV DNA in other skin lesions beyond sarcoids implies that BPVs might contribute broadly to equine skin disease.
• These findings emphasize the importance of further research to elucidate the precise roles of various BPV genotypes in equine skin pathologies.
• Ultimately, better understanding of BPV-related disease mechanisms may guide the development of more effective, targeted treatments for equine sarcoids and other skin conditions.