Ovine footrot: new insights into bacterial colonisation.
Authors: Maboni G, Frosth S, Aspán A, Tötemeyer S
Journal: The Veterinary record
Summary
# Editorial Summary: Ovine Footrot and Bacterial Colonisation Footrot in sheep progresses from interdigital dermatitis (ID) through to severe under-running of the hoof horn, yet the microbial mechanisms driving this progression remain incompletely understood. Maboni and colleagues examined postslaughter biopsies (n=241) from healthy, affected and diseased ovine interdigital skin using real-time PCR to quantify colonisation levels of *Dichelobacter nodosus*, *Fusobacterium necrophorum* and *Treponema* species, whilst also characterising the virulence profiles of recovered *D. nodosus* strains. Peak prevalence and bacterial load of *D. nodosus* occurred in feet exhibiting ID rather than advanced footrot, suggesting a critical window during early dermatitis when pathogenic colonisation becomes established, and notably the samples contained predominantly virulent *D. nodosus* isolates with some harbouring both virulent and benign strains concurrently; UK samples also yielded the more pathogenic subspecies of *F. necrophorum*. These findings highlight that footrot develops through a staged bacterial colonisation process, with implications for intervention timing—early detection and treatment of ID may be most effective before established mixed infections and tissue damage occur, whilst the prominence of virulent strains underscores the importance of biosecurity and vaccination strategies targeting these specific pathogenic variants.
Read the full abstract on PubMed
Practical Takeaways
- •Interdigital dermatitis may represent a critical window for intervention before footrot establishment, as D. nodosus load is highest at this stage
- •Multiple bacterial species and virulence variants colonize the interdigital skin simultaneously, suggesting multifactorial disease requiring comprehensive management approaches
- •Regional variation in pathogenic bacteria (particularly F. necrophorum) may necessitate tailored treatment protocols based on geographic location
Key Findings
- •Highest prevalence and load of Dichelobacter nodosus found in feet with interdigital dermatitis rather than established footrot
- •Vast majority of samples contained virulent D. nodosus strains, with some samples harboring both virulent and benign strains concurrently
- •Pathogenic subspecies of Fusobacterium necrophorum identified in UK sheep samples, suggesting geographic variation in bacterial colonization
- •Bacterial colonization patterns suggest role in early-stage interdigital dermatitis progression toward footrot development