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Protection of foals against experimental Rhodococcus equi pneumonia by oral immunization.

Abstract: Two groups of three one to three week old foals were immunized orally on four occasions over five weeks with two strains of Rhodococcus equi, a clinical isolate from a pneumonic foal and a laboratory passaged Congo red negative variant of this strain. Three nonimmunized foals of similar age acted as controls. Three weeks after the last immunization, all foals were challenged on five occasions over seven days by aerosol infection with about 10(10) of the pneumonic foal isolate on each occasion. Control foals became seriously ill and were euthanized. Immunization with either strain protected foals equally against the challenge, and resulted in rapid lung clearance. Oral immunization can thus protect foals against severe challenge with R. equi. The proteins associated with Congo red colony staining appear not to be involved in protective immunity.
Publication Date: 1987-10-01 PubMed ID: 3453264PubMed Central: PMC1255362
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  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

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 research study trialed the effects of oral vaccinations against Rhodococcus equi pneumonia in young foals. The immunization significantly reduced illness and aided in rapid lung clearance, giving evidence that this method can protect foals against severe challenges of R. equi.

Methodology of the Study

  • The study comprised two groups of foals, each containing three foals aged one to three weeks old. Three more foals of similar age were kept separate as control.
  • Both groups of foals were orally immunized on four separate occasions over a period of five weeks using two strains of Rhodococcus equi – one was a clinical isolate obtained from a pneumonic foal, and the other was a laboratory-passaged Congo red negative variant of that same strain.
  • Three weeks after their last dose of immunization, all the foals were exposed to aerosol infection – they were subjected to about 10^10 of the pneumonic foal isolate five times over seven days.

Findings of the Study

  • The control foals that were not immunized fell ill severely and had to be euthanized to spare them further suffering.
  • On the other hand, the foals that were immunized with either strain were equally protected against the challenge, resulting in quick clearance of their lungs. This demonstrated that oral immunization can be effective at protecting foals against severe Rhodococcus equi challenges.
  • The study also noted that the proteins associated with Congo red colony staining did not seem to play a significant role in protective immunity.

Implications of the Study

  • The findings of the study suggest that oral immunization could be a feasible and effective method of protecting foals against Rhodococcus equi infections, a significant cause of pneumonia in these animals.
  • The discovery that proteins associated with Congo red colony staining don’t have a significant role in the development of protective immunity against Rhodococcus equi is crucial for future research and the development of more targeted vaccines.

Cite This Article

APA
Chirino-Trejo JM, Prescott JF, Yager JA. (1987). Protection of foals against experimental Rhodococcus equi pneumonia by oral immunization. Can J Vet Res, 51(4), 444-447.

Publication

ISSN: 0830-9000
NlmUniqueID: 8607793
Country: Canada
Language: English
Volume: 51
Issue: 4
Pages: 444-447

Researcher Affiliations

Chirino-Trejo, J M
  • Department of Veterinary Microbiology and Immunology, Ontario Veterinary College, University of Guelph.
Prescott, J F
    Yager, J A

      MeSH Terms

      • Actinomycetales Infections / prevention & control
      • Actinomycetales Infections / veterinary
      • Administration, Oral
      • Animals
      • Bacterial Vaccines / administration & dosage
      • Horse Diseases / prevention & control
      • Horses
      • Immunization / veterinary
      • Lung / pathology
      • Pneumonia / prevention & control
      • Pneumonia / veterinary
      • Rhodococcus / immunology

      References

      This article includes 12 references
      1. Can J Comp Med. 1980 Jul;44(3):280-8
        pubmed: 7427776
      2. Infect Immun. 1984 Jan;43(1):397-401
        pubmed: 6360906
      3. Can J Comp Med. 1979 Oct;43(4):356-64
        pubmed: 548158
      4. Vet Pathol. 1983 Jul;20(4):450-9
        pubmed: 6623849
      5. Am J Vet Res. 1985 Oct;46(10):2171-4
        pubmed: 4062025
      6. J Am Vet Med Assoc. 1982 Nov 15;181(10):1074-9
        pubmed: 6294027
      7. Can Vet J. 1986 May;27(5):213-7
        pubmed: 17422658
      8. Vet Pathol. 1983 Jul;20(4):440-9
        pubmed: 6623848
      9. J Clin Microbiol. 1986 Apr;23(4):794-6
        pubmed: 3700632
      10. Am J Vet Res. 1985 Jan;46(1):13-5
        pubmed: 3918488
      11. J Clin Microbiol. 1983 Sep;18(3):486-90
        pubmed: 6630438
      12. Equine Vet J. 1982 Apr;14(2):111-6
        pubmed: 7084193

      Citations

      This article has been cited 16 times.
      1. da Silveira BP, Kahn SK, Legere RM, Bray JM, Cole-Pfeiffer HM, Golding MC, Cohen ND, Bordin AI. Enteral immunization with live bacteria reprograms innate immune cells and protects neonatal foals from pneumonia. Sci Rep 2025 May 25;15(1):18156.
        doi: 10.1038/s41598-025-02060-5pubmed: 40415003google scholar: lookup
      2. da Silveira BP, Cohen ND, Lawhon SD, Watson RO, Bordin AI. Protective immune response against Rhodococcus equi: An innate immunity-focused review. Equine Vet J 2025 May;57(3):563-586.
        doi: 10.1111/evj.14214pubmed: 39258739google scholar: lookup
      3. Liu L, Cai P, Gu W, Duan X, Gao S, Ma X, Ma Y, Ma S, Li G, Wang X, Cai K, Wang Y, Cai T, Zhao H. Evaluation of vaccine candidates against Rhodococcus equi in BALB/c mice infection model: cellular and humoral immune responses. BMC Microbiol 2024 Jul 8;24(1):249.
        doi: 10.1186/s12866-024-03408-zpubmed: 38977999google scholar: lookup
      4. Knox A, Zerna G, Beddoe T. Current and Future Advances in the Detection and Surveillance of Biosecurity-Relevant Equine Bacterial Diseases Using Loop-Mediated Isothermal Amplification (LAMP). Animals (Basel) 2023 Aug 18;13(16).
        doi: 10.3390/ani13162663pubmed: 37627456google scholar: lookup
      5. Cohen ND, Kahn SK, Bordin AI, Gonzales GM, da Silveira BP, Bray JM, Legere RM, Ramirez-Cortez SC. Association of pneumonia with concentrations of virulent Rhodococcus equi in fecal swabs of foals before and after intrabronchial infection with virulent R. equi. J Vet Intern Med 2022 May;36(3):1139-1145.
        doi: 10.1111/jvim.16409pubmed: 35322902google scholar: lookup
      6. Giles C, Ndi O, Barton MD, Vanniasinkam T. An Adenoviral Vector Based Vaccine for Rhodococcus equi. PLoS One 2016;11(3):e0152149.
        doi: 10.1371/journal.pone.0152149pubmed: 27008624google scholar: lookup
      7. Rocha JN, Cohen ND, Bordin AI, Brake CN, Giguère S, Coleman MC, Alaniz RC, Lawhon SD, Mwangi W, Pillai SD. Oral Administration of Electron-Beam Inactivated Rhodococcus equi Failed to Protect Foals against Intrabronchial Infection with Live, Virulent R. equi. PLoS One 2016;11(2):e0148111.
        doi: 10.1371/journal.pone.0148111pubmed: 26828865google scholar: lookup
      8. Bordin AI, Pillai SD, Brake C, Bagley KB, Bourquin JR, Coleman M, Oliveira FN, Mwangi W, McMurray DN, Love CC, Felippe MJ, Cohen ND. Immunogenicity of an electron beam inactivated Rhodococcus equi vaccine in neonatal foals. PLoS One 2014;9(8):e105367.
        doi: 10.1371/journal.pone.0105367pubmed: 25153708google scholar: lookup
      9. Bordin AI, Suchodolski JS, Markel ME, Weaver KB, Steiner JM, Dowd SE, Pillai S, Cohen ND. Effects of administration of live or inactivated virulent Rhodococccus equi and age on the fecal microbiome of neonatal foals. PLoS One 2013;8(6):e66640.
        doi: 10.1371/journal.pone.0066640pubmed: 23785508google scholar: lookup
      10. Harris SP, Hines MT, Mealey RH, Alperin DC, Hines SA. Early development of cytotoxic T lymphocytes in neonatal foals following oral inoculation with Rhodococcus equi. Vet Immunol Immunopathol 2011 Jun 15;141(3-4):312-6.
        doi: 10.1016/j.vetimm.2011.03.015pubmed: 21481947google scholar: lookup
      11. Prescott JF, Machang'u R, Kwiecien J, Delaney K. Prevention of foal mortality due to Rhodococcus equi pneumonia on an endemically affected farm. Can Vet J 1989 Nov;30(11):871-5.
        pubmed: 17423454
      12. Jacks S, Giguère S, Crawford PC, Castleman WL. Experimental infection of neonatal foals with Rhodococcus equi triggers adult-like gamma interferon induction. Clin Vaccine Immunol 2007 Jun;14(6):669-77.
        doi: 10.1128/CVI.00042-07pubmed: 17409222google scholar: lookup
      13. Jacks S, Giguère S, Prescott JF. In vivo expression of and cell-mediated immune responses to the plasmid-encoded virulence-associated proteins of Rhodococcus equi in foals. Clin Vaccine Immunol 2007 Apr;14(4):369-74.
        doi: 10.1128/CVI.00448-06pubmed: 17301216google scholar: lookup
      14. Giguère S, Prescott JF. Cytokine induction in murine macrophages infected with virulent and avirulent Rhodococcus equi. Infect Immun 1998 May;66(5):1848-54.
      15. Ross TL, Balson GA, Miners JS, Smith GD, Shewen PE, Prescott JF, Yager JA. Role of CD4+, CD8+ and double negative T-cells in the protection of SCID/beige mice against respiratory challenge with Rhodococcus equi. Can J Vet Res 1996 Jul;60(3):186-92.
        pubmed: 8809381
      16. Prescott JF. Rhodococcus equi: an animal and human pathogen. Clin Microbiol Rev 1991 Jan;4(1):20-34.
        doi: 10.1128/CMR.4.1.20pubmed: 2004346google scholar: lookup