Clinical and histopathological findings in mice heavily infected with Fibricola seoulensis.

To observe the clinical course and intestinal histopathology in heavy infection of Fibricola seoulensis, an experimental study was performed in mice. Clinical, hematological and histopathological observation was done on 1, 3, 7 and 12 days after experimental infection with l,000 metacercariae. On the 11th day after infection, the mice began to die and all of the infected mice were dead by the 16th day. The infected mice showed gradual weight loss. Occult blood was detected after the 10th day. Diarrhea occurred after the 9th day and was recognized in all of the infected mice on the 12th day. Hemoglobin and mean corpuscular hemoglobin decreased significantly after the 12th day, and mean corpuscular hemoglobin concentration decreased in all infected mice. The histopathological changes were more marked in the duodenum than in the jejunum or ileum. Major changes were villous atrophy and crypt hyperplasia, with decreased villus/crypt ratio, inflammatory cell infiltration and stromal edema. The present results suggest that the cause of death of mice heavily infected with F. seoulensis should be malnutrition and severe fluid loss due to malabsorption, together with intestinal bleeding.