Current understanding of the aetiology and laboratory diagnosis of footrot.
Authors: Wani S A, Samanta I
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Footrot Aetiology and Laboratory Diagnosis Footrot in ruminants results from synergistic bacterial infection with *Dichelobacter nodosus* as the primary aetiological agent, though the disease has occasionally been reported in horses, cattle, pigs and deer. Antigenic diversity within *D. nodosus* populations arises from variations in the fimbrial subunit gene (fimA), enabling classification into at least 10 major serogroups (A–I and M) with geographically distinct distributions—a critical consideration for vaccination strategies, since immune responses prove serogroup-specific. The organism exists as virulent, intermediate and benign strains, each producing different clinical manifestations and requiring differentiation for appropriate management. Contemporary diagnostic advances including immunological assays, DNA probes and PCR-based techniques now enable rapid identification of strain virulence, serogroup classification and strain differentiation, substantially improving the precision of disease control programmes. For equine and other species practitioners, understanding *D. nodosus* taxonomy and the availability of these molecular diagnostic tools becomes relevant when footrot occurs outside typical ruminant populations, allowing informed decisions about treatment protocols and biosecurity measures tailored to the specific strain and virulence profile involved.
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Practical Takeaways
- •Footrot diagnosis and control require serogroup-specific approaches since vaccine immunity and strain characteristics vary geographically
- •Clinical presentation varies from benign to virulent forms; molecular testing is now available to differentiate strains and guide treatment decisions
- •Understanding antigenic diversity of D. nodosus strains is essential for developing effective vaccination and control programs tailored to local disease variants
Key Findings
- •Footrot is caused by synergistic action of bacterial species with Dichelobacter nodosus as the primary transmitting agent
- •D. nodosus contains at least 10 major serogroups (A-I and M) based on fimbrial subunit gene (fimA) variations with geographically variable distribution
- •Three clinical disease forms exist corresponding to virulent, intermediate, and benign D. nodosus strains
- •PCR-based techniques, DNA probes, and immunological tests enable rapid diagnosis, virulence determination, and serogroup identification for disease control