A new strain of Taylorella asinigenitalis shows differing pathogenicity in mares and Jenny donkeys.
Authors: Wilsher Sandra, Omar Hussein, Ismer Ann, Allen Twink, Wernery Ulli, Joseph Marina, Mawhinney Ian, Florea Laura, Thurston Lisa, Duquesne Fabien, Petry Sandrine
Journal: Equine veterinary journal
Summary
# Editorial Summary Taylorella asinigenitalis, a venereal pathogen typically associated with donkeys, demonstrated striking species-specific pathogenicity when a new strain was transmitted from an infected jack donkey to equines through breeding. Three mares developed severe purulent endometritis requiring clinical intervention, whilst two jenny donkeys mated naturally to the same jack showed no clinical signs of infection, prompting investigation into the causative organism and its virulence characteristics. Endometrial swabs from affected mares were cultured under aerobic and microaerophilic conditions and subjected to multiple identification methods including Gram staining, oxidase and catalase testing, latex agglutination, and PCR confirmation for both T. equigenitalis and T. asinigenitalis; molecular genotyping via MLST revealed a previously uncharacterised sequence type. This novel strain's differential pathogenicity between equine and donkey hosts has important implications for breeding programmes involving cross-species semen use and highlights that established biosecurity protocols around T. equigenitalis may require reassessment when donkey genetics are introduced into equine populations. Practitioners should consider T. asinigenitalis as a differential diagnosis in mares with unexplained endometritis, particularly where there has been contact with donkey breeding stock, and recognise that standard screening may need adaptation to detect this emerging strain reliably.
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Practical Takeaways
- •When using donkey semen for equine breeding, screen Jack donkeys for T. asinigenitalis as infected animals may transmit severe venereal disease to mares despite showing no symptoms
- •Donkeys appear to be asymptomatic carriers of T. asinigenitalis, making them potential reservoir hosts; Jenny donkeys can be naturally mated without clinical consequences but mares show severe endometritis
- •Implement biosecurity protocols when cross-breeding between equine and donkey species, including bacterial culture and PCR testing of semen donors
Key Findings
- •A new sequence type of T. asinigenitalis was identified in semen from an infected Jack donkey
- •Three mares inseminated with semen from the positive Jack donkey developed severe purulent endometritis
- •Two Jenny donkeys mated naturally to the same Jack donkey showed no clinical signs of infection
- •The strain demonstrates differential pathogenicity between equine and donkey species