Hematologic values in calves infected with Sarcocystis cruzi

Area of Science:

• Veterinary Parasitology
• Animal Immunology
• Hematology

Background:

• Sarcocystis cruzi is an intracellular protozoan parasite that infects cattle.
• Understanding the hematological and immunological impact of Sarcocystis cruzi infection is crucial for cattle health management.

Purpose of the Study:

• To investigate the hematological alterations and immune responses in calves experimentally infected with Sarcocystis cruzi.

Main Methods:

• Calves were inoculated with a specific dose of Sarcocystis cruzi sporocysts.
• Blood volume, red cell mass, and plasma volume were monitored over time.
• Erythrocyte parameters, including reticulocyte count and enzyme activity (pyrimidine 5' nucleotidase), were assessed.
• Antiglobulin tests (direct Coombs tests) were performed to detect antibody and complement deposition on erythrocytes.

Main Results:

• A significant reduction in red cell mass was observed between 21 and 35 days post-infection.
• Plasma volume increased concurrently, resulting in no significant change in total blood volume.
• Mild reticulocytosis and elevated erythrocyte pyrimidine 5' nucleotidase activity were noted from 35 to 42 days post-infection.
• Antiglobulin tests were predominantly negative, with one positive C3 test in six infected calves.

Conclusions:

• Sarcocystis cruzi infection induces significant hematological changes in calves, primarily affecting red blood cell mass.
• The observed changes suggest a potential hemolytic process or impaired erythropoiesis.
• The limited positive antiglobulin test indicates a minimal role of antibody- or complement-mediated hemolysis in this experimental model.