The possible role of Stomoxys calcitrans in equine sarcoid transmission.
Authors: Haspeslagh M, Vlaminck L, Martens A
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Bovine Papillomavirus and Stable Flies in Equine Sarcoid Transmission Whilst bovine papillomavirus (BPV) is established as the aetiological agent in equine sarcoids, the transmission route remains poorly understood—particularly how isolated horses develop the disease without direct contact with infected animals. Haspeslagh and colleagues exposed 420 BPV-negative stable flies (*Stomoxys calcitrans*) to BPV-positive equine sarcoid or bovine papilloma tissue under controlled conditions, then tracked viral DNA presence in dead flies daily over the following week using quantitative PCR. Both sarcoid and papilloma exposure resulted in significantly elevated BPV loads within the flies, though virus persisted longer and at higher titres following papilloma contact compared to sarcoid tissue; critically, detectable viral loads diminished to baseline levels within days of initial exposure. These findings suggest that stable flies could theoretically serve as mechanical vectors for BPV, though transmission appears temporally restricted to the immediate post-feeding period and may be more epidemiologically relevant following exposure to bovine rather than equine lesions. For practitioners managing sarcoid cases, this research underscores the potential importance of fly control measures alongside conventional therapies, and highlights why geographically isolated horses with sarcoid histories warrant investigation into concurrent cattle exposure or trading contacts.
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Practical Takeaways
- •Stable fly control may be a useful management strategy to reduce potential BPV transmission risk in equine operations, particularly where sarcoid-affected horses are present
- •Isolated equids developing sarcoids without direct contact to affected animals may warrant investigation of stable fly populations as a possible exposure route
- •Further research is needed before firm clinical recommendations can be made; this study demonstrates possibility but not confirmed transmission under field conditions
Key Findings
- •BPV-negative stable flies (Stomoxys calcitrans) accumulated significantly higher BPV loads after exposure to both equine sarcoid and bovine papilloma tissue
- •Viral load remained elevated longer and reached higher levels in papilloma-exposed flies compared to sarcoid-exposed flies
- •BPV loads decreased to baseline levels within days of tissue exposure in all groups
- •Results suggest S. calcitrans could potentially transmit BPV but transmission window is limited to shortly after tissue contact