Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals.
Abstract: To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. Methods: Prospective case-control study. Methods: 5230 foals on 138 breeding farms with 9136 horses. Methods: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. Results: A number of variables relating to farm size and desirable management practices were significantly associated with increased odds of farms being affected with R equi pneumonia. By use of multivariate logistic regression, affected farms were determined significantly more likely to have raised Thoroughbreds, housed > or =15 foals, used concrete floors in foaling stalls, and tested foals for passive transfer of immunity than unaffected farms. These results remained significant even after accounting for exposure of foals to other breeding farms during the first month of life. Conclusions and Clinical Relevance-Breeding farms with large acreage and a large number of mares and foals have greater odds of being affected by R equi pneumonia. Clinical relevance of associations with Thoroughbred breed and concrete flooring in foaling stalls remains uncertain. Desirable management factors commonly used on farms were not effective for controlling or preventing development of R equi pneumonia. This finding indicates a need to focus on host factors that influence disease development.
Publication Date: 2005-02-11 PubMed ID: 15702691DOI: 10.2460/javma.2005.226.404Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research article discusses the identification of farm characteristics and management practices that are associated with the development of Rhodococcus equi pneumonia in foals. To this end, the researchers conducted a case-control study involving 5230 foals on 138 breeding farms.
Methods
- The study took place in 2003 and included 5230 foals across 138 breeding farms. The farms in question were those where one or more foals developed Rhodococcus equi pneumonia, and farms where no cases of the disease were reported.
- Veterinarians provided data on the condition of foals on each farm. The management practices and characteristics of affected and non-affected farms were compared using a logistic regression analysis. This allowed the researchers to identify key factors that were associated with an increased likelihood of the disease developing.
Findings
- The results showed that several factors relating to the size of the farm and specific management practices significantly increased the odds of farms experiencing cases of R equi pneumonia. Notably, the cases were higher in farms that raised Thoroughbred foals, had more than 15 foals, and used concrete floors in foaling stalls.
- Interestingly, testing foals for passive transfer of immunity was found to be more common in affected farms. This observation might suggest that such testing, generally considered a good practice, was not in itself sufficient to prevent the disease. This remained true even when the possibility of foals exposure to other breeding farms during the first month of life was taken into account.
Implications and Applications
- The findings suggest that larger breeding farms with more extensive acreage and a higher number of mares and foals are more susceptible to outbreaks of R equi pneumonia.
- The role of the Thoroughbred breed, as well as the use of concrete flooring in foaling stalls, in promoting the disease is yet to be understood completely. It remains uncertain whether these are causally linked to the disease or are simple correlations.
- The fact that commonly used management practices fell short of effectively controlling or preventing the disease implies that more attention needs to be paid to the host factors that influence disease development. This could pave the way for a more strategic, host-based approach to pneumonia prevention in foals.
Cite This Article
APA
Cohen ND, O'Conor MS, Chaffin MK, Martens RJ.
(2005).
Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals.
J Am Vet Med Assoc, 226(3), 404-413.
https://doi.org/10.2460/javma.2005.226.404 Publication
Researcher Affiliations
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4475, USA.
MeSH Terms
- Actinomycetales Infections / epidemiology
- Actinomycetales Infections / microbiology
- Actinomycetales Infections / veterinary
- Animal Husbandry / methods
- Animals
- Animals, Newborn
- Case-Control Studies
- Female
- Floors and Floorcoverings
- Horse Diseases / epidemiology
- Horse Diseases / microbiology
- Horses
- Logistic Models
- Male
- Pneumonia, Bacterial / epidemiology
- Pneumonia, Bacterial / microbiology
- Pneumonia, Bacterial / veterinary
- Population Density
- Prospective Studies
- Rhodococcus equi
- United States / epidemiology
Citations
This article has been cited 15 times.- Yerlikaya Z, Karagülle B, Otlu B, Muz A. From Paddock to Foal: Prevalence and Genotypic Diversity of Rhodococcus equi on Stud Farms in Türkiye. Vet Sci 2026 Jan 10;13(1).
- Villalba-Orero M, Gómez CA, Valero-Gónzalez M, Venegas N, Criado G, Martín-Cuervo M. Blood parameters in neonatal foal and colostrum quality as possible early markers for increased risk of developing Rhodococcus equi pneumonia. Front Vet Sci 2025;12:1654052.
- Rakowska A, Czopowicz M, Bereznowski A, Witkowski L. Investigation of the relationship between pulmonary lesions based on lung ultrasound and respiratory clinical signs in foals with suspected pulmonary rhodococcosis. Sci Rep 2023 Nov 8;13(1):19401.
- 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.
- Kahn SK, Cywes-Bentley C, Blodgett GP, Canaday NM, Turner-Garcia CE, Flores-Ahlschwede P, Metcalfe LL, Nevill M, Vinacur M, Sutter PJ, Meyer SC, Bordin AI, Pier GB, Cohen ND. Randomized, controlled trial comparing Rhodococcus equi and poly-N-acetyl glucosamine hyperimmune plasma to prevent R equi pneumonia in foals. J Vet Intern Med 2021 Nov;35(6):2912-2919.
- Kahn SK, Cywes-Bentley C, Blodgett GP, Canaday NM, Turner-Garcia CE, Vinacur M, Cortez-Ramirez SC, Sutter PJ, Meyer SC, Bordin AI, Vlock DR, Pier GB, Cohen ND. Antibody activities in hyperimmune plasma against the Rhodococcus equi virulence -associated protein A or poly-N-acetyl glucosamine are associated with protection of foals against rhodococcal pneumonia. PLoS One 2021;16(8):e0250133.
- Cohen ND, Kahn SK, Cywes-Bentley C, Ramirez-Cortez S, Schuckert AE, Vinacur M, Bordin AI, Pier GB. Serum Antibody Activity against Poly-N-Acetyl Glucosamine (PNAG), but Not PNAG Vaccination Status, Is Associated with Protecting Newborn Foals against Intrabronchial Infection with Rhodococcus equi. Microbiol Spectr 2021 Sep 3;9(1):e0063821.
- Löhr CV, O'Neill TW, Daw DN, Pitel MO, Schlipf JW. Pyogranulomatous enteritis and mesenteric lymphadenitis in an adult llama caused by Rhodococcus equi carrying virulence-associated protein A gene. J Vet Diagn Invest 2019 Sep;31(5):747-751.
- Padalino B, Rogers CW, Guiver D, Bridges JP, Riley CB. Risk Factors for Transport-Related Problem Behaviors in Horses: A New Zealand Survey. Animals (Basel) 2018 Aug 2;8(8).
- Javed R, Taku AK, Sharma RK, Badroo GA. Molecular characterization of Rhodococcus equi isolates in equines. Vet World 2017 Jan;10(1):6-10.
- Padalino B, Raidal SL, Hall E, Knight P, Celi P, Jeffcott L, Muscatello G. A Survey on Transport Management Practices Associated with Injuries and Health Problems in Horses. PLoS One 2016;11(9):e0162371.
- Krewer Cda C, Spricigo DA, de Avila Botton S, da Costa MM, Schrank I, de Vargas AC. Molecular characterization of Rhodococcus equi Isolates of horse breeding farms from an endemic region in South of Brazil by multiplex PCR. Braz J Microbiol 2008 Jan;39(1):188-93.
- Summer EJ, Liu M, Gill JJ, Grant M, Chan-Cortes TN, Ferguson L, Janes C, Lange K, Bertoli M, Moore C, Orchard RC, Cohen ND, Young R. Genomic and functional analyses of Rhodococcus equi phages ReqiPepy6, ReqiPoco6, ReqiPine5, and ReqiDocB7. Appl Environ Microbiol 2011 Jan;77(2):669-83.
- Coulson GB, Agarwal S, Hondalus MK. Characterization of the role of the pathogenicity island and vapG in the virulence of the intracellular actinomycete pathogen Rhodococcus equi. Infect Immun 2010 Aug;78(8):3323-34.
- Flaminio MJ, Nydam DV, Marquis H, Matychak MB, Giguère S. Foal monocyte-derived dendritic cells become activated upon Rhodococcus equi infection. Clin Vaccine Immunol 2009 Feb;16(2):176-83.
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