Central Nervous System Disorders Caused by Parasites in Horses

Parasites are organisms that must live in other living things (called "hosts") to survive. Some parasites, specifically worms and insect larvae (the immature, developing form of the insect), can affect the brain and spinal cord in horses. Diagnosis usually requires ruling out other causes of central nervous system (CNS) symptoms and, when possible, identifying the parasite involved.

Myiasis is an infestation of parts of the body by fly larvae (“maggots”). In rare cases, fly larvae can be found migrating in the horse's brain and spinal cord. Symptoms include incoordination and abnormal behavior. Some insect-killing drugs can kill the larvae, but treatment can also trigger inflammation in the horse's nervous system. Anti-inflammatory drugs are often used to relieve swelling and pressure on the brain and spinal cord caused by treatment.