FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Journal of veterinary internal medicine2018; 32(3); 1210-1214; doi: 10.1111/jvim.15127

Protozoal coinfection in horses with equine protozoal myeloencephalitis in the eastern United States.

Abstract: Infection by 2 or more protozoa is linked with increased severity of disease in marine mammals with protozoan encephalitis. Objective: To assess whether horses with equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona also have evidence of infection with Neospora hughesi or Toxoplasma gondii. We hypothesized that horses with EPM would be more likely than horses with cervical vertebral stenotic myelopathy (CVSM) to be positive for antibodies to multiple protozoan parasites. Methods: One hundred one horses with neurologic disease: 49 with EPM and 52 with CVSM. Methods: Case review. Archived serum and cerebrospinal fluid (CSF) from 101 horses were examined. Inclusion criteria included neurologic disease, antemortem or postmortem diagnosis of EPM or CVSM, and availability of serological results or archived samples for testing. Additional testing for antibodies was performed on serum for T. gondii, as well as serum and CSF for N. hughesi. Results: Horses with EPM were more likely than horses with CVSM to have positive immunologic results for S. neurona on serum (95.9% versus 76.9%, P = .0058), CSF (98.0% versus 44.2%, P < .00001), and serum : CSF titer ratio (91.8% versus 0%, P < .00001). Positive results for Neospora and Toxoplasma were uncommon, with total seroprevalence rates of 12.9% and 14.9%, respectively. The proportions of EPM cases testing positive for Neospora and Toxoplasma (16% and 12%) were not different from the proportions of CVSM cases testing positive (10% and 17%, P = .31 and .47, respectively). Conclusions: Results do not indicate an important role for protozoal coinfection in EPM in the eastern United States.
Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
Get Full Text
Publication Date: 2018-04-10 PubMed ID: 29633348PubMed Central: PMC5980325DOI: 10.1111/jvim.15127Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study aims to assess whether horses with the neurologic disease, equine protozoal myeloencephalitis (EPM), also have infections with other protozoa such as Neospora hughesi or Toxoplasma gondii. However, the findings suggest that protozoal coinfection may not play a significant role in EPM cases in the eastern United States.

Objectives and Hypothesis of the Study

The study aims to:

  • Determine whether horses with EPM are prone to other protozoal infections such as Neospora hughesi and Toxoplasma gondii.
  • Test the hypothesis that these horses are more likely to have antibodies to multiple protozoan parasites compared with horses suffering from another neurologic disease, cervical vertebral stenotic myelopathy (CVSM).

Methodology

The research was carried out as follows:

  • The study involved 101 horses suffering from neurologic disorders, 49 had EPM and 52 had CVSM.
  • Samples of both serum and cerebrospinal fluid (CSF) were taken from the horses.
  • The presence of antibodies to the protozoa was indicated by positive testing results. The antibodies were detected via immunoassays, tests that use the immune response for detecting diseases.
  • The researchers tested the samples for antibodies against T. gondii and N. hughesi.

Results

The study resulted in the following findings:

  • Horses with EPM were shown to be more likely to have positive test results for S. neurona in serum and CSF than those with CVSM. This shows a strong correlation between EPM and S. neurona infection.
  • However, positive results for antibodies to Neospora and Toxoplasma were relatively uncommon, suggesting a low rate of coinfection with these protozoa.
  • There was no significant difference between the proportions of EPM cases and CVSM cases testing positive for Neospora and Toxoplasma, contradicting the initial hypothesis.

Conclusion

The study concluded that protozoal coinfections do not seem to play a significant role in EPM in the eastern United States, as positive results for additional protozoal infections were infrequent.

Cite This Article

APA
Schale S, Howe D, Yeargan M, Morrow JK, Graves A, Johnson AL. (2018). Protozoal coinfection in horses with equine protozoal myeloencephalitis in the eastern United States. J Vet Intern Med, 32(3), 1210-1214. https://doi.org/10.1111/jvim.15127

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 32
Issue: 3
Pages: 1210-1214

Researcher Affiliations

Schale, Sarah
  • Department of Clinical Studies, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon.
Howe, Daniel
  • Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky.
Yeargan, Michelle
  • Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky.
Morrow, Jennifer K
  • Equine Diagnostic Solutions, LLC, Lexington, Kentucky.
Graves, Amy
  • Equine Diagnostic Solutions, LLC, Lexington, Kentucky.
Johnson, Amy L
  • Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania.

MeSH Terms

  • Animals
  • Antibodies, Protozoan / blood
  • Coccidiosis / complications
  • Coccidiosis / parasitology
  • Coccidiosis / veterinary
  • Coinfection / parasitology
  • Coinfection / veterinary
  • Encephalomyelitis / parasitology
  • Encephalomyelitis / veterinary
  • Horse Diseases / parasitology
  • Horses
  • Neospora
  • Pennsylvania
  • Sarcocystis
  • Sarcocystosis / complications
  • Sarcocystosis / parasitology
  • Sarcocystosis / veterinary
  • Toxoplasma
  • Toxoplasmosis, Animal / complications
  • Toxoplasmosis, Animal / parasitology
  • Toxoplasmosis, Animal / pathology

References

This article includes 31 references
  1. Reed SM, Furr M, Howe DK, Johnson AL, MacKay RJ, Morrow JK, Pusterla N, Witonsky S. Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and Prevention.. J Vet Intern Med 2016 Mar-Apr;30(2):491-502.
    pmc: PMC4913613pubmed: 26857902doi: 10.1111/jvim.13834google scholar: lookup
  2. Howe DK, MacKay RJ, Reed SM. Equine protozoal myeloencephalitis.. Vet Clin North Am Equine Pract 2014 Dec;30(3):659-75.
    pubmed: 25441115doi: 10.1016/j.cveq.2014.08.012google scholar: lookup
  3. Reed SM, Howe DK, Morrow JK, Graves A, Yeargan MR, Johnson AL, MacKay RJ, Furr M, Saville WJ, Williams NM. Accurate antemortem diagnosis of equine protozoal myeloencephalitis (EPM) based on detecting intrathecal antibodies against Sarcocystis neurona using the SnSAG2 and SnSAG4/3 ELISAs.. J Vet Intern Med 2013 Sep-Oct;27(5):1193-200.
    pubmed: 24033423doi: 10.1111/jvim.12158google scholar: lookup
  4. Johnson AL, Morrow JK, Sweeney RW. Indirect fluorescent antibody test and surface antigen ELISAs for antemortem diagnosis of equine protozoal myeloencephalitis.. J Vet Intern Med 2013 May-Jun;27(3):596-9.
    pubmed: 23517480doi: 10.1111/jvim.12061google scholar: lookup
  5. Keusch GT, Migasena P. Biological implications of polyparasitism.. Rev Infect Dis 1982 Jul-Aug;4(4):880-2.
    pubmed: 6750751doi: 10.1093/4.4.880google scholar: lookup
  6. Supali T, Verweij JJ, Wiria AE, Djuardi Y, Hamid F, Kaisar MM, Wammes LJ, van Lieshout L, Luty AJ, Sartono E, Yazdanbakhsh M. Polyparasitism and its impact on the immune system.. Int J Parasitol 2010 Aug 15;40(10):1171-6.
    pubmed: 20580905doi: 10.1016/j.ijpara.2010.05.003google scholar: lookup
  7. Graham AL. When T-helper cells don't help: immunopathology during concomitant infection.. Q Rev Biol 2002 Dec;77(4):409-34.
    pubmed: 12599914doi: 10.1086/344414google scholar: lookup
  8. Nacher M. Interactions between worms and malaria: good worms or bad worms?. Malar J 2011 Sep 12;10:259.
    pmc: PMC3192711pubmed: 21910854doi: 10.1186/1475-2875-10-259google scholar: lookup
  9. Liesenfeld O, Dunay IR, Erb KJ. Infection with Toxoplasma gondii reduces established and developing Th2 responses induced by Nippostrongylus brasiliensis infection.. Infect Immun 2004 Jul;72(7):3812-22.
    pmc: PMC427426pubmed: 15213122doi: 10.1128/IAI.72.7.3812-3822.2004google scholar: lookup
  10. Gibson AK, Raverty S, Lambourn DM, Huggins J, Magargal SL, Grigg ME. Polyparasitism is associated with increased disease severity in Toxoplasma gondii-infected marine sentinel species.. PLoS Negl Trop Dis 2011 May;5(5):e1142.
    pmc: PMC3101184pubmed: 21629726doi: 10.1371/journal.pntd.0001142google scholar: lookup
  11. James KE, Smith WA, Conrad PA, Packham AE, Guerrero L, Ng M, Pusterla N. Seroprevalences of anti-Sarcocystis neurona and anti-Neospora hughesi antibodies among healthy equids in the United States.. J Am Vet Med Assoc 2017 Jun 1;250(11):1291-1301.
    pubmed: 28509641doi: 10.2460/javma.250.11.1291google scholar: lookup
  12. Pusterla N, Tamez-Trevino E, White A, Vangeem J, Packham A, Conrad PA, Kass P. Comparison of prevalence factors in horses with and without seropositivity to Neospora hughesi and/or Sarcocystis neurona.. Vet J 2014 May;200(2):332-4.
    pubmed: 24703324doi: 10.1016/j.tvjl.2014.03.014google scholar: lookup
  13. Finno CJ, Aleman M, Pusterla N. Equine protozoal myeloencephalitis associated with neosporosis in 3 horses.. J Vet Intern Med 2007 Nov-Dec;21(6):1405-8.
    pubmed: 18196754doi: 10.1892/07-054.1google scholar: lookup
  14. Hoane JS, Yeargan MR, Stamper S, Saville WJ, Morrow JK, Lindsay DS, Howe DK. Recombinant NhSAG1 ELISA: a sensitive and specific assay for detecting antibodies against Neospora hughesi in equine serum.. J Parasitol 2005 Apr;91(2):446-52.
    pubmed: 15986623doi: 10.1645/GE-395Rgoogle scholar: lookup
  15. Packham AE, Conrad PA, Wilson WD, Jeanes LV, Sverlow KW, Gardner IA, Daft BM, Marsh AE, Blagburn BL, Ferraro GL, Barr BC. Qualitative evaluation of selective tests for detection of Neospora hughesi antibodies in serum and cerebrospinal fluid of experimentally infected horses.. J Parasitol 2002 Dec;88(6):1239-46.
    pubmed: 12537119doi: 10.1645/0022-3395(2002)088[1239:QEOSTF]2.0.CO;2google scholar: lookup
  16. Furr M, Kennedy T, MacKay R, Reed S, Andrews F, Bernard B, Bain F, Byars D. Efficacy of ponazuril 15% oral paste as a treatment for equine protozoal myeloencephalitis.. Vet Ther 2001 Summer;2(3):215-22.
    pubmed: 19746664
  17. Furr M, Howe D, Reed S, Yeargan M. Antibody coefficients for the diagnosis of equine protozoal myeloencephalitis.. J Vet Intern Med 2011 Jan-Feb;25(1):138-42.
    pubmed: 21155894doi: 10.1111/j.1939-1676.2010.0658.xgoogle scholar: lookup
  18. Dubey JP, Mitchell SM, Morrow JK, Rhyan JC, Stewart LM, Granstrom DE, Romand S, Thulliez P, Saville WJ, Lindsay DS. Prevalence of antibodies to Neospora caninum, Sarcocystis neurona, and Toxoplasma gondii in wild horses from central Wyoming.. J Parasitol 2003 Aug;89(4):716-20.
    pubmed: 14533680doi: 10.1645/GE-66Rgoogle scholar: lookup
  19. Dangoudoubiyam S, Oliveira JB, Víquez C, Gómez-García A, González O, Romero JJ, Kwok OC, Dubey JP, Howe DK. Detection of antibodies against Sarcocystis neurona, Neospora spp., and Toxoplasma gondii in horses from Costa Rica.. J Parasitol 2011 Jun;97(3):522-4.
    pubmed: 21506839doi: 10.1645/GE-2722.1google scholar: lookup
  20. Jakubek EB, Lundén A, Uggla A. Seroprevalences of Toxoplasma gondii and Neospora sp. infections in Swedish horses.. Vet Parasitol 2006 Jun 15;138(3-4):194-9.
    pubmed: 16517077doi: 10.1016/j.vetpar.2006.02.002google scholar: lookup
  21. James KE, Smith WA, Packham AE, Conrad PA, Pusterla N. Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case-control study of Californian horses.. Vet J 2017 Jun;224:38-43.
    pubmed: 28697873doi: 10.1016/j.tvjl.2017.05.008google scholar: lookup
  22. Tissot Dupont D, Fricker-Hidalgo H, Brenier-Pinchart MP, Bost-Bru C, Ambroise-Thomas P, Pelloux H. Usefulness of Western blot in serological follow-up of newborns suspected of congenital toxoplasmosis.. Eur J Clin Microbiol Infect Dis 2003 Feb;22(2):122-5.
    pubmed: 12627289doi: 10.1007/s10096-003-0887-5google scholar: lookup
  23. Harkins D, Clements DN, Maley S, Marks J, Wright S, Esteban I, Innes EA, Buxton D. Western blot analysis of the IgG responses of ruminants infected with Neospora caninum and with Toxoplasma gondii.. J Comp Pathol 1998 Jul;119(1):45-55.
    pubmed: 9717126doi: 10.1016/s0021-9975(98)80070-4google scholar: lookup
  24. Gu Y, Wang Z, Cai Y, Li X, Wei F, Shang L, Li J, Liu Q. A comparative study of Toxoplasma gondii seroprevalence in mink using a modified agglutination test, a Western blot, and enzyme-linked immunosorbent assays.. J Vet Diagn Invest 2015 Sep;27(5):616-20.
    pubmed: 26199291doi: 10.1177/1040638715596033google scholar: lookup
  25. Howe DK, Summers BC, Sibley LD. Acute virulence in mice is associated with markers on chromosome VIII in Toxoplasma gondii.. Infect Immun 1996 Dec;64(12):5193-8.
    pmc: PMC174507pubmed: 8945565doi: 10.1128/iai.64.12.5193-5198.1996google scholar: lookup
  26. Su C, Howe DK, Dubey JP, Ajioka JW, Sibley LD. Identification of quantitative trait loci controlling acute virulence in Toxoplasma gondii.. Proc Natl Acad Sci U S A 2002 Aug 6;99(16):10753-8.
    pmc: PMC125035pubmed: 12149482doi: 10.1073/pnas.172117099google scholar: lookup
  27. Campbell I. Chi-squared and Fisher-Irwin tests of two-by-two tables with small sample recommendations.. Stat Med 2007 Aug 30;26(19):3661-75.
    pubmed: 17315184doi: 10.1002/sim.2832google scholar: lookup
  28. Richardson JT. The analysis of 2 × 2 contingency tables--yet again.. Stat Med 2011 Apr 15;30(8):890; author reply 891-2.
    pubmed: 21432882doi: 10.1002/sim.4116google scholar: lookup
  29. Tassi P. Toxoplasma gondii infection in horses. A review.. Parassitologia 2007 Jun;49(1-2):7-15.
    pubmed: 18412038
  30. Sundar N, Cole RA, Thomas NJ, Majumdar D, Dubey JP, Su C. Genetic diversity among sea otter isolates of Toxoplasma gondii.. Vet Parasitol 2008 Feb 14;151(2-4):125-32.
    pubmed: 18155841doi: 10.1016/j.vetpar.2007.11.012google scholar: lookup
  31. Dubey JP, Thulliez P, Romand S, Kwok OC, Shen SK, Gamble HR. Serologic prevalence of Toxoplasma gondii in horses slaughtered for food in North America.. Vet Parasitol 1999 Oct 15;86(4):235-8.
    pubmed: 10536980doi: 10.1016/s0304-4017(99)00148-xgoogle scholar: lookup

Citations

This article has been cited 5 times.
  1. Stelzer S, Basso W, Benavides Silván J, Ortega-Mora LM, Maksimov P, Gethmann J, Conraths FJ, Schares G. Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact. Food Waterborne Parasitol 2019 Jun;15:e00037.
    doi: 10.1016/j.fawpar.2019.e00037pubmed: 32095611google scholar: lookup
  2. Schai-Braun SC, Posautz A, Alves PC, Hackländer K. Gastrointestinal parasite infestation in the alpine mountain hare (Lepus timidus varronis): Are abiotic environmental factors such as elevation, temperature and precipitation affecting prevalence of parasite species?. Int J Parasitol Parasites Wildl 2019 Aug;9:202-208.
    doi: 10.1016/j.ijppaw.2019.05.009pubmed: 31193935google scholar: lookup
  3. Alsakini KAMH, Al-Ammiri HH, Touma MM. Serologic and molecular survey of Toxoplasma gondii in Baghdad Province, Iraq. Open Vet J 2025 Jun;15(6):2492-2499.
    doi: 10.5455/OVJ.2025.v15.i6.21pubmed: 40989605google scholar: lookup
  4. Valderrama-Martinez C, Packham A, Smith W, Mendoza-Flores JE, Zheng S, Chigerwe M, Plancarte M, Aleman M. Effect of Long-Term Freezing on Indirect Fluorescent Antibody Titers for the Diagnosis of Equine Protozoal Myeloencephalitis. J Vet Intern Med 2025 Sep-Oct;39(5):e70225.
    doi: 10.1111/jvim.70225pubmed: 40873183google scholar: lookup
  5. Elmahallawy EK, Hassan MF, Cano-Terriza D, Albalawi NO, Fajardo T, Gouda AA, Atiba A, Hendawy A, Villena I, Barakat AM, Alzaylaee H, Almería S, García-Bocanegra I. Seroepidemiological study of Toxoplasma gondii in equines in Northern Egypt. Front Vet Sci 2025;12:1561145.
    doi: 10.3389/fvets.2025.1561145pubmed: 40458764google scholar: lookup
Subscribe to our newsletter
Join 99,727 horse owners like you who receive our email updates on horse health and nutrition.