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Home / Equine Research Bank / J Vet Diagn Invest / Prevalence of potential enteric pathogens in diarrheic and n...
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc2026; 10406387261423226; doi: 10.1177/10406387261423226

Prevalence of potential enteric pathogens in diarrheic and non-diarrheic foals in Brazil.

Abstract: Diarrhea is a significant cause of morbidity and mortality in foals. Our hypothesis is that foals with diarrhea have a greater prevalence of ≥2 organisms causing coinfections. We investigated the major microorganisms associated with diarrhea in 200 foals up to 1-y-old (100 diarrheic and 100 non-diarrheic). Fecal samples were analyzed by real-time PCR (rtPCR) for the detection of and toxin genes and , (genotyping for toxin-encoding genes), spp., , , , , , and spp. Rotavirus A and coronavirus were detected using reverse-transcription rtPCR. Fecal bacterial culture was also performed for and , and isolates were submitted for the detection of toxin-encoding genes (conventional multiplex PCR). At least one enteric agent was detected by rtPCR in 85% and 70% of diarrheic and non-diarrheic foals, respectively. Co-detection was significantly more frequent in the diarrheic group (27 singly detected organisms vs. 58 co-detected organisms) than in the non-diarrheic group (37 singly detected organisms vs. 33 co-detected organisms;  = 0.008). spp., (and toxigenic ), and spp. were significantly associated with foal diarrhea. Our detection of multiple agents in diarrheic foals highlights the diagnostic complexity and potential interactions among agents in the multifactorial etiology of foal diarrhea.
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Publication Date: 2026-03-17 PubMed ID: 41846283PubMed Central: PMC12999535DOI: 10.1177/10406387261423226Google Scholar: Lookup
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  • Journal Article

Summary

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Overview

  • This study investigated the prevalence and co-occurrence of multiple enteric pathogens in diarrheic and non-diarrheic foals in Brazil to understand their role in causing diarrhea.
  • It found that foals with diarrhea had a higher frequency of coinfections with two or more pathogens compared to healthy foals, highlighting the complex cause of foal diarrhea.

Background and Objective

  • Diarrhea is a major health problem causing illness and death in foals (young horses up to 1 year old).
  • The researchers hypothesized that foals suffering from diarrhea would have a greater prevalence of two or more enteric pathogens simultaneously (coinfections) compared to foals without diarrhea.
  • The aim was to identify and compare the major microorganisms associated with diarrhea in diarrheic and non-diarrheic foals.

Study Design and Methods

  • Total of 200 foals studied: 100 with diarrhea and 100 without diarrhea.
  • Fecal samples were collected and analyzed using molecular biology techniques:
    • Real-time PCR (rtPCR) to detect DNA/RNA of various pathogens and specific toxin genes encoding virulence factors.
    • Reverse-transcription rtPCR for detecting RNA viruses: Rotavirus A and coronavirus.
    • Fecal bacterial cultures were performed to isolate bacteria like Clostridium perfringens and Clostridium difficile, followed by PCR to detect their toxin genes.
  • Pathogens tested included multiple bacteria species (such as Clostridium spp., Salmonella spp., Escherichia coli) and viruses known to cause enteric (gastrointestinal) infections in foals.

Key Results

  • At least one enteric pathogen was detected in:
    • 85% of diarrheic foals.
    • 70% of non-diarrheic foals.
  • Coinfections (two or more organisms present) were significantly more frequent in foals with diarrhea:
    • In diarrheic foals: 58 cases showed co-detection, vs. 27 cases with single organism detection.
    • In non-diarrheic foals: 33 co-detections vs. 37 single organism detections.
  • Specific pathogens significantly associated with diarrhea included:
    • Clostridium perfringens (especially toxigenic strains).
    • Salmonella spp.
    • Clostridium difficile.
  • Presence of multiple pathogens in diarrheic foals suggests complex interactions contributing to disease, rather than a single causative agent.

Interpretation and Implications

  • The higher prevalence of coinfections in diarrheic foals underscores the multifactorial nature of foal diarrhea where multiple pathogens may act synergistically or sequentially to cause illness.
  • Detection of multiple agents complicates clinical diagnosis and treatment, indicating the necessity for comprehensive testing rather than targeting a single pathogen.
  • Identifying toxigenic bacteria highlights the role of bacterial toxins in the disease process and potential targets for therapeutic intervention or prevention.
  • The findings emphasize the importance of thorough microbiological surveillance and possibly tailored antimicrobial or vaccination strategies to reduce mortality in foals caused by diarrheal disease.

Conclusions

  • Foals with diarrhea in Brazil are more likely to harbor multiple enteric pathogens simultaneously compared to healthy foals.
  • Management and diagnostic protocols for foal diarrhea should consider the presence of coinfections to better guide treatment decisions.
  • This research advances understanding of the complex etiology of equine diarrhea and supports the development of improved control measures in equine medicine.

Cite This Article

APA
Basso RM, Cerri FM, Braga PRC, Silva ROS, de Araújo Júnior JP, Oliveira-Filho JP, Pantoja JCF, Ribeiro MG, Arroyo LG, Borges AS. (2026). Prevalence of potential enteric pathogens in diarrheic and non-diarrheic foals in Brazil. J Vet Diagn Invest, 10406387261423226. https://doi.org/10.1177/10406387261423226

Publication

Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
ISSN: 1943-4936
NlmUniqueID: 9011490
Country: United States
Language: English
Pages: 10406387261423226
PII: 10406387261423226

Researcher Affiliations

Basso, Roberta Martins
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Cerri, Fabrício Moreira
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Braga, Pollyana Rennó Campos
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Silva, Rodrigo Otávio Silveira
  • Sao Paulo State University, Botucatu, Sao Paulo, Brazil; Veterinary School, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
de Araújo Júnior, João Pessoa
  • Institute of Biotechnology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil (Araújo Júnior).
Oliveira-Filho, José Paes de
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Pantoja, José Carlos de Figueiredo
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Ribeiro, Márcio Garcia
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Arroyo, Luis G
  • Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Borges, Alexandre Secorun
  • School of Veterinary Medicine and Animal Science, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.

Conflict of Interest Statement

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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