[Size of hepatic granuloma produced by eggs of 2 geographic strains of Schistosoma mansoni, in mice].

The authors have determined the mean diameter of granulomas in the liver of mice infected with cercariae from two different and well definite geographic strains of Schistosoma mansoni (LE, Belo Horizonte, MG, and SJ, São José dos Campos, SP). A total of 1,170 granulomas has been measured. Granulomas measured on the 60th day after infection showed larger size than the other ones measured on the 90th day. Modulation of the immunopathologic response was significantly more efficient for the LE strain, whereas the granulomas (with 60 and 90 days) related to SJ strain were significantly larger. Data suggested a higher pathogenicity for the SJ strain. It is speculated whether these findings could explain, in part, the occurrence of regional variations of the anatomo-clinical forms of schistosomiasis.