Gut Microbes Differ in Healthy and Allergic Dogs

Jim Crocker
28th August, 2025

Gut Microbes Differ in Healthy and Allergic Dogs

West Highland Whiter Terrier

Pixabay

Key Findings

  • This study, conducted in Switzerland with West Highland White Terrier dogs, investigated gut bacteria differences between dogs with and without atopic dermatitis (cAD)
  • Researchers found no major differences in the overall variety or composition of gut bacteria between allergic and healthy WHWTs
  • A moderate negative correlation was observed between the amount of E. coli bacteria in the gut and the severity of itchiness, suggesting a possible link between this bacteria and cAD symptoms
Canine atopic dermatitis (cAD) is a common, inflammatory skin disease in dogs, often inherited and seen in many breeds, with the West Highland White Terrier (WHWT) being particularly prone to it. The disease causes itchy skin and inflammation, frequently leading to secondary infections. Understanding the causes of cAD is complex, and research suggests a combination of genetic factors and environmental triggers are at play. Recent work by researchers at the University of Zurich[1] investigated whether the gut microbiome – the community of bacteria living in the dog’s digestive system – might be involved in the development of cAD in WHWTs. The idea that the gut microbiome plays a role in allergic diseases isn’t new. Studies in humans have shown links between gut bacteria and conditions like eczema, and some research in dogs suggests similar connections[2]. However, the specific relationship in WHWTs, a breed known for its susceptibility to cAD, hadn’t been explored. The aim of the University of Zurich study was to compare the gut bacteria of WHWTs with cAD to those of healthy WHWTs, looking for differences that might explain why some dogs develop the disease and others don’t. The study involved collecting fecal samples from 21 WHWTs – 12 diagnosed with cAD and 9 healthy dogs. To analyze the bacteria present, the researchers used DNA shotgun sequencing, a method that identifies all the genetic material in a sample, allowing them to determine which bacterial species are present and in what amounts. They also used qPCR assays, a technique to quantify specific bacterial groups. Surprisingly, the researchers found no major differences in the overall diversity of gut bacteria between the allergic and healthy dogs. Alpha diversity refers to the variety of bacteria within a single sample, while beta diversity describes the differences in bacterial composition between samples. Neither showed significant variation. They also didn’t find a clear difference in the abundance of any particular bacterial groups between the two groups. This was measured using the Dysbiosis Index (DI), which assesses the balance of ‘good’ and ‘bad’ bacteria; the DI scores were similar in both groups. However, the study did reveal a moderate negative correlation between the amount of E. coli bacteria in the gut and the severity of the dog’s itchiness (pruritus). This means that dogs with more E. coli in their gut tended to have less severe itching. It’s important to note that correlation doesn’t equal causation – the E. coli might not be causing the reduced itch, but could be linked in some other way. The findings of this study contrast with some previous research linking gut microbiome imbalances to allergic diseases[3]. While the study by the University of Zurich didn’t find widespread differences in gut bacteria composition, the correlation with E. coli suggests that specific bacterial species might play a role in cAD symptoms, even if the overall microbiome appears relatively normal. Previous genetic studies in WHWTs affected by cAD haven’t identified specific genes responsible for the condition[4], highlighting the complexity of the disease. The University of Zurich’s research suggests that the gut microbiome may be one piece of the puzzle, interacting with genetic predisposition and environmental factors. This study opens the door for further research investigating the specific mechanisms by which E. coli might influence itchiness in WHWTs, and whether manipulating the gut microbiome could be a potential therapeutic strategy for managing cAD. Researchers acknowledge that a larger study, involving more dogs and potentially looking at other aspects of gut health (using what they refer to as ‘multi-omics approaches’) is needed to confirm these findings and fully understand the role of the gut microbiome in cAD.

HealthGeneticsAnimal Science

References

Main Study

1) An insight into the gut microbiota of healthy and allergic West Highland Whiter Terrier dogs

Published 27th August, 2025

https://doi.org/10.1371/journal.pone.0328100

Related Studies

2) Atopic dermatitis in cats and dogs: a difficult disease for animals and owners.

https://doi.org/10.1186/s13601-018-0228-5

3) Differences in Gut Microbiota Between Atopic and Healthy Children.

https://doi.org/10.1007/s00284-015-0815-9

4) Genome-wide linkage study of atopic dermatitis in West Highland White Terriers.

https://doi.org/10.1186/1471-2156-12-37


Related Articles

An unhandled error has occurred. Reload 🗙