Strangles is a highly contagious bacterial disease caused by Streptococcus equi. It is spread by direct contact with infected horses or carriers. The disease can also be transmitted via contaminated water troughs/buckets, feed bunks/buckets, stalls, tack, trailers, and people. It usually affects young horses but can afflict animals of any age. Horses in high-density management systems (i.e. breeding farms) and those in high traffic areas such as shows and events are at higher risk of being exposed and infected by S. equi. There are however, many steps horse owners can take to protect their horse from the disease.

West Nile Virus produces lesions in the gray matter of the mid-brain, hind-brain, and spinal cord. Lesions tend to increase in severity the closer they are to the hindquarters. Lesions can be symmetrical or asymmetrical, effecting both or only one side of the horse. They can also be in more than one location, so combinations of clinical signs may vary.

Equine Protozoal Myeloencephalitis, or EPM, is one of the most common neurological diseases affecting the horse. Most horses exposed to the causative organism, Sarcocystis neurona, will clear any infection with their own immune system. However, in horses with a compromised immune system, the organism can spread to the central nervous system causing a very serious and debilitating disease.