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*'''Whole organism indirect fluorescent antibody test (IFAT)''': sensitivity around 90%, specificity 97-100%.<ref name="EPM4>Johnson, A.L (2008) Evidence-based clinical question: which is the most sensitive and specific commercial test to diagnose ''Sarcocystis neurona'' infection (equine protozoal myeloencephalitis) in horses?, ''Equine Vet Educ'', 20(3):166-168.</ref>  Serum titres of more than 1:100 and CSF titres of more than 1:5 indicate an active infection. The IFAT is considered to have slightly improved diagnostic efficiency than the immunoblot test<ref>Duarte, P.C, Daft, B.M, Conrad, P.A, Packham, A.E, Gardner, I.A (2003) Comparison of a serum indirect fluorescent antibody test with two Western blot tests for the diagnosis of equine protozoal myeloencephalitis, ''J Vet Diagn Invest'', 15:8-13.  In: Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref> but is unable to distinguish between ''S.neurona'' and other related nonpathogenic organsims such as ''S.fayeri''(94 in Furr).  This can lead to false positive results.  Compared with the immunblot test, CSF blood contamination has an insignificant effect on the IFAT.(11 in IVIS 4)  An IFAT for ''N.hughesi'' is also available from the Universty of California.<ref name="Furr">Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref>
 
*'''Whole organism indirect fluorescent antibody test (IFAT)''': sensitivity around 90%, specificity 97-100%.<ref name="EPM4>Johnson, A.L (2008) Evidence-based clinical question: which is the most sensitive and specific commercial test to diagnose ''Sarcocystis neurona'' infection (equine protozoal myeloencephalitis) in horses?, ''Equine Vet Educ'', 20(3):166-168.</ref>  Serum titres of more than 1:100 and CSF titres of more than 1:5 indicate an active infection. The IFAT is considered to have slightly improved diagnostic efficiency than the immunoblot test<ref>Duarte, P.C, Daft, B.M, Conrad, P.A, Packham, A.E, Gardner, I.A (2003) Comparison of a serum indirect fluorescent antibody test with two Western blot tests for the diagnosis of equine protozoal myeloencephalitis, ''J Vet Diagn Invest'', 15:8-13.  In: Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref> but is unable to distinguish between ''S.neurona'' and other related nonpathogenic organsims such as ''S.fayeri''(94 in Furr).  This can lead to false positive results.  Compared with the immunblot test, CSF blood contamination has an insignificant effect on the IFAT.(11 in IVIS 4)  An IFAT for ''N.hughesi'' is also available from the Universty of California.<ref name="Furr">Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref>
 
*'''ELISA for antibodies to the snSAG-1 protein''': based on an immunodominant surface antigen of ''S.neurona'' (SAG-1).<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>  Serum titres more than 1:100 suggest an active infection.  False negatives are possible as not all ''S.neurona'' isolates produce the specific protein.<ref>Howe, D, Gaji, R, Marsh, A (2008) Strains of ''S.neurona'' exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.  ''Int J Parasitol'', 38:623-631.  In: Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref>  SAG-5 is an alternative surface antigen of ''S.neurona'' strains, which is mutually exclusive to SAG-1.<ref>Crowdus, C.A, Marsh, A.E, Saville, W.J, ''et al''. (2008) SnSAG5 is an
 
*'''ELISA for antibodies to the snSAG-1 protein''': based on an immunodominant surface antigen of ''S.neurona'' (SAG-1).<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>  Serum titres more than 1:100 suggest an active infection.  False negatives are possible as not all ''S.neurona'' isolates produce the specific protein.<ref>Howe, D, Gaji, R, Marsh, A (2008) Strains of ''S.neurona'' exhibit differences in their surface antigens, including the absence of the major surface antigen SnSAG1.  ''Int J Parasitol'', 38:623-631.  In: Furr, M (2010) ''Equine protozoal myeloencephalitis'' in Reed, S.M, Bayly, W.M. and Sellon, D.C (2010) '''Equine Internal Medicine''' (Third Edition), ''Saunders'', Chapter 12.</ref>  SAG-5 is an alternative surface antigen of ''S.neurona'' strains, which is mutually exclusive to SAG-1.<ref>Crowdus, C.A, Marsh, A.E, Saville, W.J, ''et al''. (2008) SnSAG5 is an
alternative surface antigen of ''Sarcocystis neurona'' strains that is mutually exclusive to SnSAG1. ''Vet Parasitol'', 158:36–43. In: IVIS 4Therefore, the ELISA may only be of use where strains of ''S.neurona'' expressing SAG-1 predominate.<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>
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alternative surface antigen of ''Sarcocystis neurona'' strains that is mutually exclusive to SnSAG1. ''Vet Parasitol'', 158:36–43.</ref>  Therefore, the ELISA may only be of use where strains of ''S.neurona'' expressing SAG-1 predominate.<ref name="Johnson">Johnson, A.L (2009) Evidence-based review of diagnosis and treatment of ''Sarcocystis neurona'' infection (Equine Protozoal Myeloencephalitis).  ''Proceedings of the Annual Convention of the AAEP'' - Las Vegas, NV, USA, 55:172-176.</ref>
    
===Other tests===
 
===Other tests===
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