Phenotypical characterization of intestinal Schistosoma japonicum granulomas in pigs.

The pig has been proposed as a model for human schistosomiasis japonica and the use of this animal model is increasing. The inflammatory response to schistosome infection in the liver and intestine of the pig shows morphological differences, and only the hepatic granulomas have been phenotypically characterized. The aim of the present study was to phenotypically characterize the cellular inflammatory response in the cecum by immunohistochemistry with particular reference to perioval granulomatous reactions in Schistosoma japonicum infected pigs. Six pigs were exposed to 2000 cercariae and examined 9 weeks post-infection. Three uninfected pigs of the same age served as controls. Exposed pigs developed patent infections with the total number of worms between 6 and 110. Cecal granulomas were dominated by CD3 positive T-lymphocytes and IgG positive plasma cells. Despite the difference in the inflammatory response between the liver and the cecum, the results from this study indicate that the phenotypic cellular composition of cecal granulomas appears similar to what has previously been described in the liver.