Abstract
Blantidium coli (B. coli) is one of the most important causes of gastroenteritis in non human primates (NHPs), it mainly affects the colon of the host, and usually it is not pathogenic and due to the resistance of the host it rarely causes a serious disease. We here describe a case of Balantidium coli infection (Balantidiasis) in a 5 years old male hamadryas baboon (Papio hamadryas) in a pet shop in Saudi Arabia. The baboon had shown loss of appetite, and watery diarrhea. Two days later he started vomiting, and had shown severe bloody diarrhea. Microscopical examination for fecal sample revealed ciliated protozoa identified as Balantidium coli, which confirmed the diagnosis of balantidiasis.