Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 10, 1999
Publication Date: N/A
Interpretive Summary: Sarcocystis neurona is a single-celled parasite. It is the main cause of a neurologic disease of horses called equine protozoal myeloencephalitis (EPM). The parasite affects the brain and spinal cord of the horses and often causes paralysis of hind limbs. There is no satisfactory treatment for EPM. Sulfonamides and pyrimethamine are the 2 drugs most commonly used to treat horses. Scientists at the Beltsville Agricultural Research Center and Virginia Tech, Blacksburg have developed an in vitro cell culture system to screen drugs against S. neurona. They have found that diclazuril, an anticoccidial drug used in poultry, is effective in killing S. neurona in cell culture. These results will be of use to parasitologists, veterinarians, and drug companies.
Diclazuril is a benzeneacetonitrial anticoccidial that has excellent activity against to the extraintestinal stages of Toxoplasma gondii and Neospora caninum. It also is highly active against intestinal coccidia of poultry. The present study examined the efficacy of diclazuril in inhibiting merozoites production by more that 80% in cultures of S. neurona or S. falcatula treated with 0.1 ng/ml diclazuril and greater than 95% inhibition of merozoite production was observed when infected cultures were treated with 1.0 ng/ml diclazuril. Diclazuril appears to have promise as a therapeutic agent in the treatment of S. neurona induced EPM in horses and S. falcatula infections in birds.