Respiratory symptoms got you breathless? Try our equine respiratory PCR panel -- we test for 7 respiratory bacteria and viruses from 1 swab.

Neurological symptoms got you down? Try our equine neurological PCR panel -- we test for 5 neurological diseases from 1 CSF or tissue sample.

Diarrhea got you on the run? Try our equine GI / diarrhea PCR panel -- we test for 4 GI diseases from 1 fecal or swab sample.

Oh baby! Our equine breeding/abortion PCR panel tests for 5 diseases affecting breeding success from 1 swab or semen sample.

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For our international clients: Our DRY CARDS let you mail blood samples to Zoologix easily and cheaply from anywhere. Samples are small, light and stable at room temperature.

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Zoologix performs equine PCR tests for...

African horse sickness

Anaplasma phagocytophilum





Borna virus

Borrelia burgdorferi

Burkholderia mallei and pseudomallei

Clostridium difficile

Clostridium species

Contagious equine metritis (CEM)




Eastern equine encephalitis (EEE)

E. coli O157:H7

E. coli panel

Equine adenoviruses

Equine arteritis virus (EAV)

Equine hepatitis virus

Equine herpesvirus
type 1

Equine herpesvirus
type 2

Equine herpesvirus
type 3

Equine herpesvirus
type 4

Equine herpesvirus
type 5

Equine infectious anemia (EIA)

Equine parvovirus

Equine piroplasmosis

Equine protozoal myeloencephalitis (EPM)





Horsepox virus

Influenza type A

Japanese encephalitis

Lawsonia intracellularis


Lyme disease


Neospora caninum

Neospora hughesi


Potomac horse fever


Rhodococcus equi


Sarcocystis neurona

St. Louis encephalitis

Strangles (Strep equi)

Streptococcus pneumoniae




Taylorella equigenitalis

Theileria equi

Toxoplasma gondii


Trypanosoma equiperdum

Trypanosoma evansi

Venezuelan equine encephalitis (VEE)

Vesicular stomatitis

West Nile virus (WNV)

Western Equine Encephalitis (WEE)

Yersinia enterocolitica

Yersinia pseudotuberculosis

Genetic tests for...

Hyperkalemic periodic paralysis

Sarcocystis neurona PCR test for horses
equine assay data sheet

Sarcocystis neurona Most common etiologic agent of Equine protozoal myeloencephalitis

Test code:
X0004 - Ultrasensitive qualitative detection of Sarcocystis neurona by real time polymerase chain reaction

X0004 is included in P0017 - equine protozoal myeloencephalitis panel and in P0014 - equine neurological panel.


Equine protozoal myeloencephalitis (EPM), also known as "equine protozoa myelitis" is primarily caused by the apicomplexan parasite Sarcocystis neurona. EPM is the most commonly diagnosed neurologic disease of the horse in the US (Dubey et al., 2001). Based on reported surveys from individual horse owners, EPM has been labeled as the most important infectious disease facing the equine industry ( NAHMS, 2001). Several surveys conducted in Ohio have revealed greater than 50% (53.6%) of horses with circulating S. neurona antibodies (Saville et al., 1997). Opossums (Didelphis virginiana) serve as definitive hosts for S. neurona in the US and are responsible for shedding infective S. neurona sporocysts (Fenger et al., 1997; Dubey and Lindsay, 1998). However, it is not clear how opossums become infected because hosts harboring sarcocysts have not been identified. Recently, S. neurona sarcocysts have been identified in the muscles of cats, raccoons, armadillos, sea otters and skunks. Recent studies from Michigan and Florida have reported S. neurona antibodies in 5% of domestic cats. A subsequent study has confirmed domestic cats to be natural carriers of this parasite (Stanek et al., 2003).

Horses are an aberrant intermediate host of S. neurona. Sporocysts are eaten, pass into the small intestine and excyst there. The infective stage of the organism, the sporozoite, then enters the horse's blood stream. In some horses, these undergo several replicative cycles in endothelial cells (in blood vessels), becoming tachyzoites, and migrate to the central nervous system. They replicate asexually within neurons and microglial cells without forming tissue cysts. In the central nervous system of the horse, they slowly divide and grow, gradually destroying the nervous tissue, causing incoordination and the other clinical signs that result from EPM. At this stage, the organism cannot be transmitted to other horses. Because the organism does not encyst in horse tissues, it cannot be transmitted to opossums, even if an opossum were to eat the tissue. Therefore, the horse is a dead end host for the protozoan.


  • Help confirm the disease causing agent
  • Shorten the time required to confirm a clinical diagnosis of S. neurona infection.
  • Help ensure that animal populations are free of S. neurona
  • Early prevention of spread of this protozoan
  • Minimize personnel exposure to this protozoan
  • Safety monitoring of biological products that derive from horses and other host animals

Dubey, J.P. and Lindsay, D.S. (1998) Isolation in immunodeficient mice of Sarcocystis neurona from opossum (Didelphis virginiana) faeces, and its differentiation from Sarcocystis falcatula. Int. J. Parasitol. 28:1823–1828..
Dubey, J.P., Lindsay, D.S., Saville, W.J.A., Reed, S.M., Granstrom, D.E. and Speer, C.A. (2001) A review of Sarcocystis neurona and equine protozoal myeloencephalitis (EPM). Vet. Parasitol. 95: 89–131.
Fenger, C.K., Granstrom, D.E., Langemeier, J.L. and Stamper, S. (1997) Epizootic of equine protozoal myeloencephalitis on a farm. J. Am. Vet. Med. Assoc 210: 923–927.
NAHMS (2001). Equine Protozoal Myeloencephalitis (EPM) in the US. APHIS:VS, CEAH, National Animal Health Monitoring System. USDA, Fort Collins, CO.
Saville, W.J.A., Reed, S.M., Granstrom, D.E., Hinchcliff, K.W., Kohn, C.W., Wittum, T.E. and Stamper, S. (1997) Prevalence of serum antibodies to Sarcocystis neurona in horses residing in Ohio. J. Am. Vet. Med. Assoc. 210:519–524.
Stanek, J.F., Stich, R.W., Dubey, J.P., Reed, S.M., Njoku, C.J., Lindsay, D.S., Schmall, L.M., Johnson, G.K., LaFave, B.M. and Saville, W.J. (2003) Epidemiology of Sarcocystis neurona infections in domestic cats (Felis domesticus) and its association with equine protozoal myeloencephalitis (EPM) case farms and feral cats from a mobile spay and neuter clinic. Vet Parasitol. 117:239-49.

Specimen requirements: 0.2 ml whole blood in EDTA (purple top) tube, or 0.2 ml CSF, or 0.2 ml fresh, frozen or fixed CNS tissue.

Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected

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