If the blood test is positive, this indicates the horse has been exposed to the organism, not that it has attacked the CNS or that it will develop clinical signs. Another test called the Western blot analysis can also be conducted on the CSF and serum. The greatest value of the Western blot test on CSF is when the result is negative. Several treatment regimens have been developed. They are expensive and can last several months.
Treatment consists of antiprotozoal, anti-inflammatory, antiedema and antioxidant therapy.
Immunomodulator treatment and physical therapy may also be attempted. The antiprotozoal treatment is the cornerstone of the treatment programs. The oldest and most commonly used antiprotozoal treatment is a combination of the folate synthesis inhibitors pyrimethamine and a sulfonamide. This combination of drugs is administered orally. Relapses, particularly following stressful situations, are common.