2020 Volume 73 Issue 8 Pages 449-456
Forty-day-old weaning piglets at a farm in Kagoshima developed watery diarrhea and died in February 2019. Two piglets with diarrhea were euthanized. A large number of trophozoites of Trichomonas spp. were histologically observed in the crypt lumina of the ileum, colon, and cecum in these piglets. Numerous parasites also invaded the mucosal epithelium and lamina propria mucosae in one piglet. Genomic DNA was purified from sections of the small and large intestine, and PCR amplified products were sequenced. Tritrichomonas foetus was identified based on sequencing results. Ultrastructurally, three anterior flagella and one posterior flagellum were observed in the parasite. Numbers of caspase-3 and TUNEL-positive cells increased in crypt epithelium. Bacteriologically, non-hemolytic Escherichia coli was isolated from the piglet intestinal content. These results suggested that T. foetus has the ability to invade mucosa and induce apoptosis, and is associated with the pathogenesis of diarrhea.
