Occurrence of Treponema DNA in equine hoof canker and normal hoof tissue.

This study investigates the presence of Treponema DNA in horses suffering from hoof canker – a chronic foot disease – compared with healthy horses. The researchers found Treponema DNA was present in a majority of both diseased and healthy hoof tissue samples, though the type of Treponema varied.

Objective and methodology

• The research aimed to examine whether Treponema spp., a type of bacteria, could be involved in hoof canker, a chronic inflammation of the horse’s foot.
• The work was based on the analysis of 71 DNA samples extracted from different sources: 59 samples of canker tissues from 26 horses affected by the disease, and 12 samples from healthy foot tissues of 9 unaffected horses.
• The presence of Treponema was checked through a method called PCR and different primer pairs were used to detect a wide range of Treponema species. The method allows copying specific DNA sequences for them to be studied in detail.
• The identification of the amplified DNA (i.e. the results of the PCR) was made by sequencing and BLAST alignment, methods which allow to classify the samples.

Results and Conclusions

• Treponema DNA was found in 37 out of 59 samples from cankerous hooves and in 9 out of 12 samples from healthy hooves. Hence, Treponema was found in the majority of both diseased and healthy hoof samples.
• Although similar, there were differences in the species of Treponema detected within the diseased and healthy samples. Among the sick horses, the Canine Oral Treponema sp. and Treponema medium ssp. bovis were the most commonly present, while in the healthy samples, there were mostly Treponema refringens-like and Canine oral Treponema-like DNA.
• The T. medium ssp. bovis DNA was not found in any of the samples from healthy horses.
• Because of these results, the researchers concluded that bovine digital dermatitis-associated treponemes,which are highly similar to T. medium ssp. bovis, are found in canker lesions. Despite Treponema DNA being found also in healthy hooves, the difference concerning T. medium ssp. bovis DNA could be an important indication for disease etiology.
• However, as there are differences in the specific types of Treponema DNA between the two groups, more work is needed to ascertain whether Treponema is directly involved in the disease or is a secondary effect of another cause. This means that the exact role of the different Treponema types in the emergence of hoof canker is still unclear and requires further research.