Peer-reviewed veterinary case report
Antibodies to SnSAG1 protein help protect horses from equine
By Ellison, Siobhan & Witonsky, Sharon·Published in Canadian journal of veterinary research = Revue canadienne de recherche veterinaire·2009·Pathogenes Inc, United States·View original on PubMed →
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Original publication title: Evidence that antibodies against recombinant SnSAG1 of Sarcocystis neurona merozoites are involved in infection and immunity in equine protozoal myeloencephalitis.
- Species:
- horse
Plain-English summary
Five horses were vaccinated with a new vaccine designed to protect against equine protozoal myeloencephalitis (EPM), a serious neurological disease caused by the parasite Sarcocystis neurona. After vaccination, the horses developed antibodies that helped neutralize the parasite. When all the horses were later exposed to the parasite, the vaccinated horses showed fewer symptoms compared to the control group, with only one horse experiencing mild weakness in a limb. This suggests that the vaccine could be effective in reducing the severity of EPM in horses.
People also search for: equine protozoal myeloencephalitis vaccine · EPM symptoms in horses · horse ataxia treatment
Abstract
Sarcocystis neurona is the principal etiologic agent of equine protozoal myeloencephalitis (EPM). An immunodominant protein of S. neurona, SnSAG-1, is expressed by the majority of S. neurona merozoites isolated from spinal tissues of horses diagnosed with EPM and may be a candidate for diagnostic tests and prophylaxis for EPM. Five horses were vaccinated with adjuvanted recombinant SnSAG1 (rSnSAG1) and 5 control (sham vaccinated) horses were vaccinated with adjuvant only. Serum was evaluated pre- and post-vaccination, prior to challenge, for antibodies against rSnSAG1 and inhibitory effects on the infectivity of S. neurona by an in vitro serum neutralization assay. The effect of vaccination with rSnSAG1 on in vivo infection by S. neurona was evaluated by challenging all the horses with S. neurona merozoites. Blinded daily examinations and 4 blinded neurological examinations were used to evaluate the presence of clinical signs of EPM. The 5 vaccinated horses developed serum and cerebrospinal fluid (CSF) titers of SnSAG1, detected by enzyme-linked immunosorbent assay (ELISA), post-vaccination. Post-vaccination serum from vaccinated horses was found to have an inhibitory effect on merozoites, demonstrated by in vitro bioassay. Following the challenge, the 5 control horses displayed clinical signs of EPM, including ataxia. While 4 of the 5 vaccinated horses did not become ataxic. One rSnSAG-1 vaccinated horse showed paresis in 1 limb with muscle atrophy. All horses showed mild, transient, cranial nerve deficits; however, disease did not progress to ataxia in rSnSAG-1 vaccinated horses. The study showed that vaccination with rSnSAG-1 produced antibodies in horses that neutralized merozoites when tested by in vitro culture and significantly reduced clinical signs demonstrated by in vivo challenge.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/19794889/