Suspected protozoal myeloencephalitis in a two-month-old colt.

This research discusses the case of a two-month-old Appaloosa colt showing neurological deficits. Various diagnostic procedures were carried out, identifying the cause to be equine protozoal myeloencephalitis, a disease caused by Sarcocystis neurona. After two months of medication, the foal returned to near-normal neurological state.

Identifying the Problem

• The Appaloosa colt showed neurological signs implicating several cranial nerves shortly after its birth. The symptoms suggested several potential causes including congenital anomalies, infections, trauma, or nutritional concerns.

Four Step Diagnostic Approach

• Electromyelography (EMG) was performed which recorded the electrical activity generated by muscle cells. In the colt’s case, EMG showed abnormal spontaneous electrical activity of the tongue, indicative of denervation.
• Magnetic Resonance Imaging (MRI) was used to create detailed images of structures within the colt’s body. The MRI was successful in ruling out potential causes of the neurological signs such as masses, congenital anomalies, and focal abscessation.
• A cerebrospinal fluid (CSF) analysis was conducted, showing mild mononuclear reactivity. The CSF is the clear fluid found in the brain and spinal cord and its analysis is crucial in diagnosing neurological disorders.
• A Western blot test, an antibody detection method, identified the presence of antibodies to Sarcocystis neurona within the colt’s CSF. This confirmed the diagnosis of equine protozoal myeloencephalitis.

Treatment and Recovery

• Once the cause was identified, the appropriate treatment was applied. Pyrimethamine and trimethoprim-sulphadiazine were administered to the colt for two months to treat the condition.
• Following the course of treatment, a significant improvement in the colt’s neurological status was reported. The foal’s condition returned to nearly normal, demonstrating the effectiveness of the applied medical treatment.