Trypanosoma cruzi infection in immunosuppressed mice

Groups of 10 mice were challenged with 10(4) trypomastigotes of the Y strain of Trypanosoma cruzi. Cyclophosphamide (200 mg per kg) was used for immunosuppression and administered two days before infection in one group and on day 5 after infection in a second group. Enhancement of infection was more drastic in the second group, with a uniform acceleration of mortality and no clearance of the blood parasites. Electron microscopy showed that the hepatocytes were colonized by T. cruzi and that the invasion of the liver, spleen and lungs was associated with secondary infection by bacteria, which may be one of the cases of acceleration of mortality in infected mice. It was suggested that immunosuppressive therapy may favor unexpected symptoms and tissue localization of parasites in patients with Chagas' disease.