No evidence of bovine papillomavirus type 1 or 2 infection in healthy equids.
Authors: Pratscher B, Hainisch E K, Sykora S, Brandt S, Jindra C
Journal: Equine veterinary journal
Summary
# Editorial Summary Bovine papillomavirus types 1 and 2 (BPV1/2) are well-established drivers of equine sarcoid development, yet their presence in clinically healthy horses has remained contentious. Pratscher and colleagues conducted a decade-long cross-sectional analysis screening 130 confirmed sarcoids, 120 suspected sarcoids, 70 non-sarcoid lesions, and crucially, 102 tumour-free horses plus 35 tumour-free donkeys and mules for BPV1/2 using highly sensitive E5-specific PCR capable of detecting fewer than 10 viral copies. All 130 confirmed sarcoids tested positive, along with 63 of the suspected cases and 13 non-sarcoid lesions; however, every single sample from clinically healthy equids returned negative, identifying six distinct BPV1 E5 variants across positive cases. The absence of BPV1/2 DNA in asymptomatic animals suggests that infection-to-sarcoid progression occurs within a relatively condensed timeframe rather than following the prolonged latency seen in humans with carcinogenic papillomaviruses, whilst the detection of viral DNA in some poor wound healing and hypergranulation cases hints at broader dermatological involvement beyond frank neoplasia. For practitioners, this work validates PCR screening of tumour material as a dependable diagnostic tool for confirming sarcoid diagnosis, and implies that BPV exposure alone does not inevitably establish persistent, clinically silent infection in healthy equids.
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Practical Takeaways
- •PCR screening for BPV1/2 DNA in tissue samples provides a reliable diagnostic tool to confirm equine sarcoid diagnosis rapidly and objectively
- •Healthy, sarcoid-free equids do not carry detectable BPV1/2 DNA, so the infection appears to require active disease rather than chronic latency
- •The presence of BPV DNA in some wound healing and dermatitis cases suggests monitoring for potential viral involvement in problematic skin healing
Key Findings
- •BPV1/2 E5 DNA was detected in 100% (130/130) of confirmed sarcoids but 0% (0/137) of tumour-free equids
- •BPV1/2 DNA was present in 63/120 suspected sarcoids and 13/70 nonsarcoid lesions, suggesting possible co-induction of other skin disorders
- •Six different BPV1 E5 variants were identified among positive samples
- •Lack of BPV1/2 DNA in healthy equids combined with sarcoid prevalence in young adults suggests short time between infection and tumour development, contrasting with human papillomavirus latency patterns