Morphological aspects of the myocarditis and myositis in Calomys callosus experimentally infected with @entity1527 : fibrogenesis and spontaneous regression of XXXX .

@entity32 @entity82 @entity1527 @entity281 @entity5895
Calomys callosus a wild rodent, is a natural host of @entity1527 . Twelve C. callosus were infected with 10(5) trypomastigotes of the F strain (a myotropic strain) of @entity1527 . @entity5895 decreased on the 21st day becoming negative around the 40th day of @entity281 . All animals survived but had positive parasitological tests, until the end of the experiment. The infected animals developed severe @entity32 in the myocardium and skeletal muscle. This process was pronounced from the 26th to the 30th day and gradually subsided from the 50th day becoming absent or residual on the 64th day after @entity281 . Collagen was identified by the picro Sirius red method. Fibrogenesis developed early, but regression of @entity82 occurred between the 50th and 64th day. Ultrastructural study disclosed a predominance of macrophages and fibroblasts in the inflammatory infiltrates, with small numbers of lymphocytes. Macrophages had active phagocytosis and showed points of contact with altered muscle cells. Different degrees of matrix expansion were present, with granular and fibrillar deposits and collagen bundles. These alterations subsided by the 64th days. Macrophages seem to be the main immune effector cell in the C. callosus model of @entity281 with @entity1527 . The mechanisms involved in the rapid fibrogenesis and its regression deserve further investigation.
