Kudoa septempunctata Spores Cause Acute Gastroenteric Symptoms in Mouse and Musk Shrew Models as Evidenced In Vitro in Human Colon Cells

is a myxosporean parasite that infects the trunk muscles of olive flounder ( ) and has been reported to cause foodborne illnesses in humans. However, the molecular mechanisms underlying spore toxicity remain largely unknown. In this study, the gastroenteropathy of was examined in human colon adenocarcinoma cells as well as experimental mice inoculated with spores. We found that decreased transepithelial resistance and disrupted epithelial tight junctions by deleting ZO-1 in Caco-2 monolayers. Additionally, serotonin (5-HT), an emetic neurotransmitter, was increased in -inoculated cells. In vivo, spores induced diarrhea in suckling mice (80% in ddY and 70% in ICR mice), with a minimum provocative dose of 2 × 10 K. spores. In house musk shrews, induced emesis within 1 h and induced serotonin secretion in the intestinal epithelium. In conclusion, may induce diarrhea and emesis by increasing intestinal permeability and serotonin secretion.