RESUMEN
The ultrastructural features and histological picture of suprarenal gland of mice infected with S. mansoni before and after acute curative treatment with praziquantel PZO were studied. The drug was given during the establishment of hepatosplenomegaly [eight weeks post- infection] given in three divided doses in one-hour interval for one day. It was shown that the most prominent histological features in infected adrenal glands were significantly reduced with an almost complete recovery after treatment. These changes as shown by electron microscope included shrinkage of the cells with wide intracellular spaces, few microvilli, Schistosoma ova, collagen and thick basement membrane-like material in the subendothelial space. These pathological features could be attributed either to the direct toxic effect of S. Mansoni ova or due to the immunological changes in the responsiveness of the host similar to the cellular changes seen elsewhere