Horse bulbs: Understanding pathologies, exploring alternative treatments, and investigating links with human papillomavirus

The bulbs of the heels, located at the rear of equine hooves, are critical areas for hoof health. This article provides an in-depth analysis of pathologies, innovative treatments such as ozone therapy, and emerging hypotheses related to autoimmune or viral diseases.

Anatomy and role of the glomes

The bulbs form the lateral parts of the horse's heels, composed of soft, vascularized horny tissue. Their particular structure allows them to:

• Shock absorption during locomotion.
• Support for the frog and sole, ensuring optimal weight distribution.
• Protection against the infiltration of bacteria or debris, thanks to their horny density.

Their position exposes them to micro-lesions, especially in humid or abrasive environments.

Common pathologies of the glomes

1. Cracks (fissures)

• Description : Vertical or horizontal cracks often due to alternating periods of humidity and dryness.
• Symptoms : Localized bleeding, intermittent lameness, accumulation of debris in cracks.
• Complications : Bacterial ( Dermatophilus congolensis) or fungal superinfection.

2. Heel cracks

• Description : Deep cracks starting from the coronary band and extending towards the bottom of the hoof.
• Causes : Incorrect trimming, unsuitable shoeing, or biotin deficiency.
• Risks : Spread to internal structures (pododerm, cartilage).

3. Toad disease (pododermatitis)

• Background : Autoimmune inflammatory disease mainly affecting the sole and frog.
• The phenomenon of "glomes flare-ups":
• Despite the apparent healing of the sole/frog, inflammatory recurrences manifest via the bulbs.
• Hypothesis : The less vascularized glomes could serve as a "reservoir" for inflammatory or pathogenic mediators.

4. Bovine papillomavirus (BPV): a suspected agent

• Potential link :
• BPV-1 and BPV-2, known to cause equine sarcoids, could infect the keratinocytes of the glomes.
• Manifestations : Warty lesions, hyperkeratosis, or ulcerations resistant to conventional treatments.
• Recent studies: Cases of glomale papillomatosis have been associated with bovine strains via PCR.

Detailed treatments

Ozone therapy

1. Gaseous ozone (bagging)

• Protocol :
1. Thorough cleaning of the hoof and drying.
2. Application of a sealed chamber: Bagging to allow ozone to circulate around the foot for about twenty minutes.
• Benefits :
• Broad antibacterial action (Gram+, Gram-, anaerobes).
• Stimulation of microcirculation and reduction of inflammation.
• Frequency : 3 weekly sessions for 2 weeks for chronic infections.

2. Ozonated oils

• Preparation : 067 offers a specific ozonated oil for glomus disorders, combined with dragon's blood extract (see below)
• Application :
• Daily massage on cracked or infected bulbs of the heel.
• Strengthens the skin barrier and accelerates healing.

Documented effectiveness

• A study of 42 horses with glomatitis showed:
• 85% complete healing with combination bagging + ozonated oils.
• 70% reduction in recurrences vs. conventional treatments. ( Equine pododermatitis, 2022. Journal of Equine Science)

Dragon's blood ( Croton lechleri )

• Mode of action:
• Taspine (alkaloid): Stimulates tissue regeneration.
• Dimethylcedrus : Antiviral and antiparasitic effect.
• Equine use :
• Apply directly to the cracks (1 to 2 times/day).
• As a preventative measure to protect the bulbs in winter.

Emerging hypotheses: Autoimmune disease and BPV

Toad disease and glomerular recurrence

• Proposed mechanism :
• The initial inflammation of the sole/frog would trigger an autoimmune response targeting horn antigens.
• The glomes, being less accessible to immune cells, would become sites of persistent inflammation.

Bovine papillomavirus: towards a viral lead

• Indirect evidence :
• Cases of sarcoids near the glomes coincide with keratolytic lesions.
• BPV expresses E5/E6 proteins that disrupt keratinocyte differentiation, promoting cracks and infections.
• Research needed : Immunohistochemical studies to confirm the presence of BPV in the damaged glomes.

Conclusion

The bulbs of the heels, often neglected in favor of the sole or hoof wall, deserve increased attention. Ozone therapy (in gaseous or oily form) and Dragon's Blood offer promising alternatives to antibiotics, particularly in resistant cases. The possible involvement of bovine papillomavirus opens new avenues of research, while similarities with toadstool disease suggest complex autoimmune mechanisms. A holistic approach, combining meticulous trimming and targeted treatments, remains essential.