● Neurologic examination ○ Confirm horse is neurologic and attempt to determine if neurologic signs localize to the brain, spinal cord, multifocal, or peripheral neuropathy.


● Contact SAHO if EHV-1(EHM), EEE/WEE/VEE, WNV or Rabies is suspected ● AAEP Neurologic Disease Differential and Diagnostic Flow Chart ● Diagnostic Testing ○ Samples to collect ■ Serum (RTT) ■ EDTA and heparin plasma (LTT and GTT) ■ Nasal swab ■ +/- CSF in both LTT & RTT. (See CSF Interpretation Chart below) ● Note: CSF is not required for diagnosis of WNV, EHV-1, and EEE but may be needed for diagnosing EPM.


■ Fresh manure should be collected if intestinal hyperammonemia is suspected


○ Clinical pathology ■ When feasible, blood ammonia should be added to standard CBC/Chem to rule out hepatic/gastrointestinal encephalopathy. Ammonia (Devriendt et al 2019) is highly labile. Samples must be collected, processed and frozen promptly or ideally run on an in-house analyzer. Contact your diagnostic laboratory for handling advice.


○ Further information regarding diagnostic sampling can be found at Diagnostic Sampling, Testing, and Handling


NOTE: Take proper precautions to prevent potential exposure to Rabies or other zoonotic pathogens while collecting samples from a neurologic horse.


● Post-mortem examination ○ Rabies, WNV, and EEE/WEE/VEE all pose potential zoonotic risk to personnel performing necropsy examinations.


○ A Rabies protocol should be followed on ALL horses exhibiting signs of neurologic disease which undergo a post-mortem examination. Detailed instruction may be found in the AAEP Rabies Guidelines.


○ The following practices are recommended to reduce exposure: ■ Submit head and/or whole body in its entirety to a local diagnostic laboratory, if possible.


■ Do NOT use mechanical saws to obtain tissue samples, as these tools may disperse aerosolized tissue particles.


■ Wear Tyvek disposable coveralls or (at a minimum) solid-front, water resistant, long-sleeved gown.


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