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Home / Equine Research Bank / Microorganisms / Multi-Kingdom Fecal Microbiota Alterations in Horses with Se...
Microorganisms2026; 14(2); 484; doi: 10.3390/microorganisms14020484

Multi-Kingdom Fecal Microbiota Alterations in Horses with Severe Equine Asthma.

Abstract: Severe equine asthma (SEA) is a chronic inflammation of airways affecting ~14-20% of adult horses in the Northern Hemisphere. SEA is characterized by a mixed phenotype of T helper cell responses with marked neutrophilia in the bronchoalveolar lavage fluid (BALF) of affected horses. Human studies have demonstrated the impact of gut microbiota in many diseases, including asthma susceptibility and severity. However, the potential role of the gut-lung axis in the development and persistence of SEA remains to be determined. This study aimed to identify key bacterial, archaeal, and fungal microbiota alterations in the feces of horses with severe neutrophilic asthma (n = 4) compared to healthy horses (n = 8). Archaea alpha diversity was lower in the feces of SEA-affected horses, but with high abundance of archaea genus , which impacts hydrogen metabolism in horses with SEA. Other key bacterial and fungi species differences lower in SEA included and , respectively. is associated with positive metabolic health due to its fibrolytic capabilities. Overall, our findings indicate that horses experiencing severe neutrophilic asthma have an imbalance in the intestinal microbiota that may exacerbate systemic inflammatory responses through the gut-lung axis.
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Publication Date: 2026-02-17 PubMed ID: 41753770PubMed Central: PMC12943238DOI: 10.3390/microorganisms14020484Google Scholar: Lookup
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  • 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.

Overview

  • This study investigates how the gut microbiota—including bacteria, archaea, and fungi—differs in horses with severe equine asthma (SEA) compared to healthy horses, suggesting that intestinal microbial imbalances may contribute to the disease’s inflammatory nature via the gut-lung axis.

Background

  • Severe equine asthma (SEA) is a chronic airway inflammation affecting 14-20% of adult horses in the Northern Hemisphere.
  • SEA is characterized by mixed T helper cell immune responses and a high presence of neutrophils in bronchoalveolar lavage fluid (BALF).
  • In humans, the gut microbiota has been linked to susceptibility and severity of asthma, indicating a possible gut-lung axis in respiratory diseases.
  • The role of the gut microbiome in SEA pathogenesis remains unclear, motivating this study to explore multi-kingdom microbial changes related to the disease.

Objectives

  • To identify alterations in bacterial, archaeal, and fungal fecal microbiota between horses with severe neutrophilic asthma (SEA) and healthy controls.

Methods

  • Fecal samples were collected from two groups: horses with SEA (n=4) and healthy horses (n=8).
  • Microbial diversity and abundance across three domains—bacteria, archaea, and fungi—were analyzed to detect differences.

Key Findings

  • Archaeal alpha diversity, which measures species richness and evenness, was lower in SEA horses, indicating less archaeal diversity.
  • Despite reduced diversity, the abundance of a particular archaeal genus associated with hydrogen metabolism was higher in SEA cases. This suggests these archaea may influence metabolic conditions related to SEA.
  • Certain beneficial bacterial species, such as those linked to positive metabolic health due to fibrolytic activity, were found in lower levels in horses with SEA.
  • Fungal species presence also differed, with some species reduced in SEA, implicating fungi as part of the microbial changes in disease.

Interpretation

  • The imbalance observed across multiple microbial kingdoms suggests dysbiosis in the gut flora of SEA-affected horses.
  • Alterations in microbes involved in fiber digestion and hydrogen metabolism could affect systemic inflammation via metabolic pathways.
  • This supports the concept of a gut-lung axis in horses, where intestinal microbes influence respiratory health and disease severity.
  • These microbial changes may exacerbate or perpetuate neutrophilic inflammation in the airways characteristic of SEA.

Significance and Future Directions

  • Understanding specific gut microbiota changes in SEA can open avenues for novel therapeutic strategies targeting the gut-lung axis.
  • Future research could investigate mechanistic links between altered microbial metabolites and airway inflammation.
  • Interventions such as probiotics, prebiotics, or dietary modulation may help restore a healthy microbial balance to mitigate asthma symptoms in horses.
  • Broader studies with larger sample sizes and longitudinal designs are needed to confirm these findings and further elucidate causality.

Cite This Article

APA
Santos R, Hunyadi L, Sundman E, Morales Luna L, Hyde SC, Cain M, Migl K, Ancira J, Tipton C, Rosa F. (2026). Multi-Kingdom Fecal Microbiota Alterations in Horses with Severe Equine Asthma. Microorganisms, 14(2), 484. https://doi.org/10.3390/microorganisms14020484

Publication

Microorganisms
ISSN: 2076-2607
NlmUniqueID: 101625893
Country: Switzerland
Language: English
Volume: 14
Issue: 2
PII: 484

Researcher Affiliations

Santos, Rafaela
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Hunyadi, Laszlo
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Sundman, Emily
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Morales Luna, Luis
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Hyde, Sarah Cate
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Cain, Makala
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Migl, Kagan
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.
Ancira, Jacob
  • Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
  • RTL Genomics, MicroGenDX, Lubbock, TX 79413, USA.
Tipton, Craig
  • RTL Genomics, MicroGenDX, Lubbock, TX 79413, USA.
Rosa, Fernanda
  • School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA.

Grant Funding

  • 2024-0000000551 / American Quarter Horse Association

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Authors Craig Tipton and Jacob Ancira are employed by RTL Genomics (Lubbock, TX, USA) and were compensated for their contributions to sequencing data analysis. However, these authors did not participate in the study design, data collection, or data interpretation. The authors have no other conflicts of interest to declare.

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