Heptatic and rectal pathology in Schistosoma intercalatum infection

Forty nine needle biopsies and 16 rectal biopsies taken from patients infected with S. intercalatum at the Ndoungué hospital (Department of Mungo, Cameroon) were studied. The histopathological changes were compared with the characteristic liver changes in S. mansoni infections. The pathological findings and clinical data were correlated in order to evaluate the extent of the liver changes in isolated S. intercalatum infections and in S. intercalatum infections assoicated with a concomitant disease. Outside the portal triangle eggs were less frequently found in S. intercalatum infection than in S. mansoni infection. This may be explained by the greater dimensions of S. intercalatum eggs. S. intercalatum granulomata, observed only in the portal triangle, had smaller dimensions than S. mansoni granulomata. S. intercalatum infection did not cause liver-cell destruction. Parenchymal lesions, when present, were always due to other causes (concomitant diseases). The liver cells sometimes showed aspecific changes such as pleomorphism of cells or nuclei or doubling of nuclei as a reaction to the toxic effect of schistosomal metabolites or to egg secretions or the inflammatory process around eggs. These changes were not associated with any impairment of liver function. No profound vascular changes such as are found in S. mansoni hepatosplenic schistosomiasis could be demonstrated; this explains the clinically noted absence of portal hypertension. Pigment formation was extensive in S. intercalatum infection; probably more pigment was present in the liver than in S. mansoni infection. In all patients the Kupffer cells were hypertrophied. The cause of the differences in the liver lesions of S. intercalatum and S. MANSONI INFECTION IN MAN MIGHT BE A LOWER IMMUNE RESPonse to S. intercalatum egg antigens.