Researchers at UC-Davis undertook a project that looked at the use of an EPM medication, diclazuril (Protazil®, Merck Animal Health), as a way to prevent EPM. Protozil is a “pelleted top dress 1.56% diclazuril antiprotozoal drug that was recently introduced for the treatment of EPM that could have the potential to be used as a preventative due to its convenient formulation”.
It was found that a low dose of this drug could reach blood and CSF (cerebral spinal fluid) levels that were higher than the concentration necessary to inhibit the protozoa (Sarcocystis neurona) responsible for EPM. Thirty-three foals from a farm with a high exposure rate to S. neurona were randomly assigned to either an untreated control group or a diclazuril-treated group.
The treatment group received diclazuril pelleted top dress starting at four weeks of age until the foals were 12 months of age. Blood was drawn and tested for IgG antibodies against S. neurona, with the first draw at 24 hours of age and then monthly until the end of the project. Results showed that both groups of foals were similar in seroprevalence (the number of foals in the population testing positive for the disease) and antibody titers until weaning. At that point, the treated group showed a significant decrease in seroprevalence as compared to the control group.
This successful reduction of S. neurona infection in the treated foals was a result of the daily, low-dose treatment of diclazuril.
Scientific Article: Pusteria, N. et al. “Use of Daily Diclazuril Pelleted Top Dress for the Prevention of Sarcocystis neurona Infection in Foals,” AAEP Proceedings, vol. 60, 2014, pp. 321-322.
Companion Article: Barakat C. and McCluskey, M. “A Way To Prevent EPM”, EQ Medical Front, Equus, April 2015, issue 451, pp. 14-16.