Chronic Diarrhea and Gut Microbiota in Cats: A Case Study of a Multifactorial Condition

Chronic diarrhea in cats is a frequent clinical problem, defined by gastrointestinal signs persisting for more than three weeks. Causes are diverse: intestinal dysbiosis, parasites, viral agents, or inflammation. Among protozoa, Tritrichomonas foetus and Cryptosporidium spp. are major contributors, while Feline Coronavirus (FCoV), though often subclinical, can worsen inflammation and dysbiosis, sometimes progressing to infectious peritonitis. This study reports a clinical case with multiple etiologies: T. foetus, Cryptosporidium spp., FCoV, and severe dysbiosis. Diagnostic workup included clinical examination, coproparasitological testing, PCR, and microbiome analysis. Treatment combined symptomatic measures with antiparasitic and antibiotic therapy. Co-infection caused persistent diarrhea and delayed therapeutic response, but PCR confirmation enabled a tailored protocol, gradually improving clinical signs. The case highlights the need for a comprehensive diagnostic approach, as concurrent infections and dysbiosis significantly affect prognosis and therapeutic strategies.