Hematologic and coagulation abnormalities in acute bovine sarcocystosis

Calves inoculated with Sarcocystis cruzi sporocysts developed severe anemia 4 weeks later. The anemic crisis was paralleled by a hyperbilirubinemia, with up to 88% of the increased total bilirubin attributed to indirect reacting bilirubin. The anemia was characterized as normocytic and normochromic. In a few instances, according to Coombs's tests (antiglobulin test) and erythrocyte eluates from infected calves, immunoglobulin G was associated with the RBC membrane. In the histopathologic examinations of tissues from calves dying during the anemic crisis, there was deposition of iron in the splenic red pulp. The hematologic studies supported the claim that the anemia in acute bovine sarcocystosis is an extravascular hemolytic event, probably with an immunologic basis. In the coagulation studies, consumption coagulopathy consistent with disseminated intravascular coagulation was seen to occur during acute sarcocystosis. At 4 weeks after inoculations were done, there were prolongations of activated partial thromboplastin and 1-stage prothrombin times and decreased functional fibrinogen concentration, and thrombocytopenia, although increase of fibrinogen-fibrin degradation products were not demonstrable. These findings indicate that endothelial parasitism by schizonts of S cruzi may cause endothelial damage, resulting in coagulation abnormalities that include disseminated intravascular coagulation.