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Scientific reports2025; 15(1); 9951; doi: 10.1038/s41598-025-94279-5

Digital droplet PCR-based detection and quantification of ovine papillomavirus DNA from the vaginal virobiota of healthy mares.

Abstract: There are four genotypes of ovine papillomaviruses (OaPVs): OaPV1, OaPV2, and OaPV4, which are ovine delta papillomaviruses responsible for epithelial and mesenchymal cell infections, and OaPV3, an epitheliotropic Dyokappapapillomavirus associated with cutaneous tumors in sheep, including squamous cell carcinoma. Vaginal swabs of healthy mares were evaluated for the presence of PVs to investigate whether the vaginal virobiota of asymptomatic mares harbored OaPVs. High-performance digital droplet polymerase chain reaction (ddPCR) was used to quantitatively detect OaPV types 1-4 DNA in 94 vaginal swabs collected at the National Reference Center for Veterinary and Comparative Oncology (CEROVEC), Genoa, Italy. All samples were comparatively evaluated for OaPV DNA loading using real-time quantitative PCR. ddPCR detected OaPV DNA in 25 vaginal swab samples (26.6%), whereas qPCR revealed 13 vaginal swabs (11.7%). Differences between the two molecular protocols were determined to be statistically significant using McNemar's test (p < 0.0005). The detected OaPV types were OaPV1 and OaPV3. Both methods failed to detect OaPV2 or OaPV4 DNA, which could be attributed to the limited number of samples examined. OaPV1 is the most prevalent OaPV in equine vaginal virobiota . This study is the first to provide evidence of the presence of OaPV DNA in vaginal swabs of healthy mares. This comparative detection approach underscores the superior sensitivity of ddPCR over qPCR.
© 2025. The Author(s).
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Publication Date: 2025-03-22 PubMed ID: 40121289PubMed Central: PMC11929744DOI: 10.1038/s41598-025-94279-5Google Scholar: Lookup
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Summary

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This research explores the detection of ovine papillomavirus (OaPV) in the vaginal virobiota of healthy mares using digital droplet polymerase chain reaction (ddPCR). The study has identified OaPV1 as the most prevalent type in equine vaginal virobiota and suggested ddPCR as a more sensitive method for detection compared to real-time quantitative PCR.

Examination of Vaginal Virobiota

  • The research assessed the presence of ovine papillomaviruses (OaPVs) in healthy mares. There are four types of OaPVs: OaPV1, OaPV2, OaPV3, and OaPV4. The first three are responsible for both epithelial and mesenchymal cell infections while OaPV3 is associated with cutaneous tumors in sheep.
  • This study used vaginal swabs from healthy mares to determine if these asymptomatic mares harbored OaPVs in their vaginal virobiota.

Detection and Quantification Method

  • High-performance digital droplet polymerase chain reaction (ddPCR) was utilized to detect OaPV types 1-4 DNA in the samples.
  • The sample comprised of 94 vaginal swabs collected at the National Reference Center for Veterinary and Comparative Oncology in Italy.
  • All the collected samples were comparatively evaluated for OaPV DNA loading using both ddPCR and real-time quantitative PCR.

Results and Significance

  • The ddPCR detected OaPV DNA in 26.6% of the samples, while qPCR revealed the presence in 13 samples, constituting 11.7% of the total count. The variation in detection rates between the two methods was statistically significant.
  • The detected OaPV types were specifically OaPV1 and OaPV3, with none of the methods managing to detect OaPV2 or OaPV4. This was attributed to the limited number of samples tested.
  • OaPV1 emerged as the most prevalent OaPV type in equine vaginal virobiota.
  • These findings are significant as they demonstrated for the first time the presence of OaPV DNA in vaginal swabs from healthy mares. The results highlighted the superior sensitivity of ddPCR over qPCR, presenting a more effective method for detection.

Cite This Article

APA
(2025). Digital droplet PCR-based detection and quantification of ovine papillomavirus DNA from the vaginal virobiota of healthy mares. Sci Rep, 15(1), 9951. https://doi.org/10.1038/s41598-025-94279-5

Publication

Scientific reports
ISSN: 2045-2322
NlmUniqueID: 101563288
Country: England
Language: English
Volume: 15
Issue: 1
Pages: 9951
PII: 9951

Researcher Affiliations

MeSH Terms

  • Animals
  • Horses / virology
  • Female
  • Vagina / virology
  • DNA, Viral / genetics
  • Papillomaviridae / genetics
  • Papillomaviridae / isolation & purification
  • Papillomavirus Infections / virology
  • Papillomavirus Infections / diagnosis
  • Papillomavirus Infections / veterinary
  • Sheep / virology
  • Real-Time Polymerase Chain Reaction / methods
  • Horse Diseases / virology
  • Horse Diseases / diagnosis

Conflict of Interest Statement

Declarations. Competing interests: The authors declare no competing interests. Ethical approval: Vaginal swabs were performed in horses admitted to the Veterinary Teaching Hospitals of Turin (OVU) for causes not related to pathologies of the genital system. All animal studies were approved by the Institutional Ethics Committee of Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d’Aosta (approval number 14047 of 11/28/2019). Permission to collect vaginal swabs was obtained from the animals’ owners who were previously informed and in agreement with the purpose and methods used.

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Citations

This article has been cited 1 times.
  1. Pereira EL, Pereira GR, Osório ML, Terra JLA, Gayger JB, Gularte JS, Demoliner M, Pereira VMAG, Filippi M, de Matos QS, Tessman A, Canal CW, Daudt C, Silva FC, Sita A, Fleck JS, Weber MN, Almeida PR, Spilki FR, da Silva MS. Bovine and ovine deltapapillomavirus coinfection associated with equine sarcoid. Braz J Microbiol 2025 Dec;56(4):2901-2908.
    doi: 10.1007/s42770-025-01759-xpubmed: 40844556google scholar: lookup
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