Daily feeding of diclazuril top dress pellets in foals reduces seroconversion to Sarcocystis neurona

Sarcocystis neurona–Induced Myeloencephalitis Relapse Following Anticoccidial Treatment

“…The horses in the mentioned study developed clinical neurologic disease as a result of the experimental S. neurona infection. While our study was performed in the immunocompromised mouse model and cannot be directly correlated to disease in the horse, the previously mentioned equine model studies by Furr et al (2006), Murphy et al (2006), and Pusterla et al (2015) also support the efficacy of humoral immune response analysis. The sera immunoglobulin results from the current study also highlight the potential for evaluating S. neurona-specific IgM antibodies clinically in equine patients, before the start of anti-protozoal treatment, at the time of treatment discontinuation and periodically after to monitor for the development of recurrent infection.…”

“…The significant increase in S. neurona antibody OD values at the time of neurologic sign also supports maturation of an immune response to S. neurona and relates the humoral immune response to S. neurona infection. Pusterla et al (2015) demonstrated that foals residing in a high-risk EPM area treated with a low dose of diclazuril (0.5 mg/kg) had significantly less sera conversion of antibodies against S. neurona compared to untreated foals following the decline of maternal antibodies. Furr et al (2006) also demonstrated the prophylactic nature of the coccidiostat Ponazuril in decreasing the incidence and severity of experimentally induced EPM, assessed by sera and CSF antibodies and clinical neurologic signs.…”

Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and Prevention

“…Diclazuril pellets, given at a low‐dose, attained plasma and CSF concentrations known to inhibit S. neurona and N. caninum in cell culture. The daily administration of a low‐dose diclazuril pellet topdressing to healthy foals from a farm with a high exposure rate to S. neurona significantly reduced the monthly seroprevalence to S. neurona when compared to untreated foals . The authors of that study suggested that the reported difference in temporal seroprevalence between treated and untreated foals was likely because of the successful reduction of S. neurona infection in foals receiving a daily low‐dose diclazuril.…”

“…The daily administration of a low-dose diclazuril pellet topdressing to healthy foals from a farm with a high exposure rate to S. neurona significantly reduced the monthly seroprevalence to S. neurona when compared to untreated foals. 122 The authors of that study suggested that the reported difference in temporal seroprevalence between treated and untreated foals was likely because of the successful reduction of S. neurona infection in foals receiving a daily low-dose diclazuril. This preventive strategy has the potential to be used in high-risk horses in an attempt to reduce the incidence of EPM, although, future longitudinal studies will be required before establishing a standard protocol.…”

Tulathromycin and Diclazuril Lack Efficacy against Theileria haneyi, but Tulathromycin Is Not Associated with Adverse Clinical Effects in Six Treated Adult Horses

“…Diclazuril is a triazine anti-protozoal drug that is currently FDA-approved for the treatment of EPM due to Sarcocystis neurona or less commonly, Neospora hughesi , and is easily accessible to U.S. producers as Protazil (1.56% ponazuril pellets, Merck Animal Health, Madison, NJ, USA) [ 24 , 25 , 26 ]. When used at an extra-label daily dose of 0.5 mg/kg, diclazuril reached adequate plasma concentrations to prevent EPM [ 27 , 28 ]. In a previous in vitro study, the related drug, ponazuril, showed efficacy against T. equi at high concentrations [ 29 ].…”