Distribution of mast cells in relation to Schistosoma japonicum induced lesions in pigs.

ABSTRACT

The pathogenesis of schistosomiasis japonica has been extensively studied, however only little attention has been paid to the presence and localization of mast cells in relation to Schistosoma japonicum induced lesions. The aim of the present pilot study was to assess the parasitological and pathological responses in S. japonicum infected pigs with emphasis on the description of the distribution of mast cells in relation to lesions in the liver and cecum. Six pigs were exposed to 2,000 cercariae and examined 9 weeks post-infection. Three unexposed pigs of the same age served as helminth free controls. All infected pigs developed granulomatous hepatitis and typhlitis. In the liver, the degree of mast cell infiltration was higher in the infected pigs compared to the unexposed control group. This distinction could not be shown in the cecum. In both the liver and cecum, a mild to moderate number of mast cells were present within the granulomas. A significant relation was found between infection with S. japonicum and the mast cell infiltration in the liver. Due to their possible association with hepatic fibrosis, it seems as if they have some function in the fibrogenic process and thereby play a dual role in the pathogenesis of S. japonicum. In conclusion, the results show that mast cells are recruited to egg induced lesions in both the liver and the cecum.