Longitudinal study of Australian stringhalt cases in France.

Area of Science:

• Veterinary Neurology
• Equine Medicine
• Toxicology

Background:

• Australian stringhalt is a neurological condition affecting horses.
• Hypochoeris radicata infestation in pastures is a suspected cause.

Purpose of the Study:

• To investigate the clinical signs, etiology, and potential treatments for Australian stringhalt.
• To understand the neurological basis and behavioral changes associated with the condition.

Main Methods:

• Clinical observation of seventy horses with Australian stringhalt in France (2003-2008).
• Assessment of pasture grazing history, particularly exposure to Hypochoeris radicata.
• Evaluation of neurological deficits, muscle atrophy, and behavioral changes.
• Monitoring response to treatments including phenytoin and taurine.

Main Results:

• Most affected horses grazed pastures infested with Hypochoeris radicata.
• The condition involves distal axonopathy, leading to hind limb hyperflexion, abnormal gait, denervation, and muscle atrophy.
• Fifty percent of horses recovered spontaneously within 8 months.
• Phenytoin showed rapid improvement in some cases, while taurine appeared to help with behavioral issues.
• Central nervous system involvement suggested by depression and aggression.

Conclusions:

• Hypochoeris radicata is strongly implicated in the etiology of Australian stringhalt.
• The condition is characterized by peripheral nerve and muscle damage, with potential central nervous system effects.
• Spontaneous recovery occurs in some cases, but targeted treatments like phenytoin and taurine can manage symptoms and behavioral disorders, especially in severe cases or specific environmental conditions.