BACKGROUND:
Chronic large-intestinal diarrhea is a frequent and complex condition in domestic cats and is often associated with mucosal inflammation and alterations in bacterial colonization. Members of the genus Helicobacter have been detected in the feline gastrointestinal tract; however, their histopathological significance in colonic disease remains incompletely understood.
OBJECTIVES:
This study aimed to evaluate histopathological alterations of the colonic mucosa in cats with and without chronic large-intestinal diarrhea and to assess the association between the presence of Helicobacter-like organisms (HLOs), lesion severity, and goblet cell changes.
METHODS:
Colonic biopsy specimens were collected endoscopically from 40 domestic cats, including 20 cats with chronic large-intestinal diarrhea and 20 non-diarrheic clinical controls. Tissue sections were stained with hematoxylin and eosin (H&E), Giemsa, and Alcian blue. Histopathological features were assessed and compared between groups. Helicobacter-like organisms were identified morphologically on Giemsa-stained sections. Statistical analyses included Chi-square and Fisher’s exact tests, with p < 0.05 considered statistically significant.
RESULTS:
Helicobacter-like organisms were detected in 16 of 40 cats (40%) and were more frequently observed in diarrheic cats (55%) than in non-diarrheic controls (25%), although this difference did not reach statistical significance (χ² = 3.75, p = 0.053; Fisher’s exact p = 0.105). HLO-positive cats more frequently exhibited crypt hyperplasia (70% vs. 12.5%), goblet cell depletion (62.5% vs. 12.5%), and moderate-to-severe mucosal lesions. Inflammatory cell infiltration was present in 82.5% of biopsies and was predominantly mononuclear, while mixed neutrophilic–mononuclear infiltrates were more common in HLO-positive cats. Goblet cell depletion was significantly associated with both HLO detection and lesion severity.
CONCLUSIONS:
The consistent co-occurrence of Helicobacter-like organisms with crypt hyperplasia, goblet cell depletion, and moderate-to-severe colonic lesions demonstrates a significant association between bacterial presence and histopathological alterations in feline colitis. Colonic biopsy supported by adjunct histochemical stains such as Giemsa and Alcian blue enhances diagnostic assessment. From a One Health perspective, reports of enterohepatic Helicobacter species in cats warrant further molecular and longitudinal studies to clarify their clinical relevance and potential zoonotic implications.