Molecular Detection of Equus caballus Papillomavirus Type 2 in Genital Swabs From Healthy Horses in the Republic of Korea.

The research article discusses a study aimed at determining the prevalence of Equus caballus papillomavirus type 2 virus in healthy horses in the Republic of Korea, particularly its presence in genital swabs, and assessing the genetic variability of the virus.

Introduction and Aim

• The study focuses on the Equus caballus papillomavirus type 2 (EcPV-2), a virus linked to genital tumors in horses, including equine penile papillomas, penile intraepithelial neoplasia, and squamous cell carcinoma (SCC).
• Though this virus rarely retreats on its own, it can lead to significant clinical damage and associated economic costs due to the development of SCC.
• Largely, the prevalence of EcPV-2 in clinically unaffected horses is not well known. This research aimed to fill this gap by determining the prevalence of EcPV-2 DNA in healthy horses in the Republic of Korea.
• The secondary aim was to explore genetic variability within EcPV-2.

Methodology

• A total of 797 genital swab samples were collected from Thoroughbred horses (35 stallions and 762 mares).
• The samples were tested for the presence of the EcPV-2 gene E1 using a Polymerase Chain Reaction (PCR) assay.
• Positively tested samples were further confirmed using a second round of PCR to detect the presence of the E6 gene and amplicon sequencing.

Results and Findings

• Out of 762 mare swab samples, 1% or 8 samples tested positive for EcPV-2 DNA. However, none of the stallion samples tested positive.
• All the EcPV-2 positive mares were imported from the United States, implying a potential geographic link to the virus.
• EcPV-2 E6 gene sequences were used for a phylogenetic analysis, revealing subdivisions related to the European strains and locating three isolates on two separate branches, providing insights into the genetic variability within EcPV-2.

Conclusion

• This study successfully establishes the molecular prevalence of EcPV-2 DNA in the healthy horse population in the Republic of Korea, contributing to a greater understanding of the virus’s reach and impact.