University of Al-Qadisiyah Al-Qadisiyah Journal of Veterinary Medicine Sciences 1818-5746 24 Special Issue ( 3 ) The 1st National and International Scientific Conference November 26 / 2025 2026 01 01 Microbiome Dysbiosis in Balantidium coli Zoonotic Infections: Emerging Mechanisms and Host Implications 12 21 190887 10.29079/qjvms.2025.164372.1108 EN Azhar Abdul Sada Neamah Department of Microbiology, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq 0000-0001-9481-6972 Khilood Hamdan Fahad Department of Microbiology, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq 0000-0002-2614-2387 Jenan Nadhim Sadeq Department of Microbiology, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq 0000-0002-6350-6311 Journal Article 2025 08 23 Balantidium coli is a rare protozoan that infects humans. It is the only known ciliate parasite in people. The infection often comes from pigs or primates. It spreads through food or water that has been contaminated. Some people have no symptoms. Others may get diarrhea, dysentery, or long-term bowel problems. Studies show that B. coli can change the gut microbiome. Helpful bacteria like Bacteroidota and short-chain fatty acid producers may decrease. Harmful bacteria such as Campylobacterota and Brachyspira may increase. These shifts can harm the gut lining and trigger inflammation. The parasite eats bacteria, damages the gut wall, and changes nutrient levels. The immune system’s reaction can also promote harmful bacteria. These changes can remain after the infection clears, raising the chance of future illness. This imbalance can weaken the gut barrier. Bacteria may then pass into the blood. The balance of short-chain fatty acids may also change, affecting colon health and metabolism. Chronic cases may cause poor nutrient absorption. Checking the gut microbiome could help diagnose the infection. It could also guide treatment. Using antiparasitic drugs with probiotics or prebiotics may help restore balance. Understanding how B. coli affects gut bacteria could lead to better ways to prevent and treat the disease in people and animals. https://qjvms.qu.edu.iq/article_190887_6d31b6216642a2c430ba19dc0c35331a.pdf