Corpuscular oxidation in newborn crossbred calves naturally infected with Theileria annulata.

Erythrocytic lipid peroxidation has been implicated as a cause of anemia in Theileria annulata infection in cattle. The present study aimed to evaluate oxidative damage of membrane lipids and proteins in addition to hemoglobin (Hb) as three criterions of erythrocyte oxidation and their relation to erythrocyte deformability and anemia of newborn crossbred calves (Friesian × Egyptian Balady breed) naturally infected with T. annulata. Twenty-five T. annulata-infected calves (aged 20-30 days) along with 15 age matched healthy controls were used. Percentage of parasitemia varied from 12% to 63% (34.76 ± 3.05%). In comparison to controls, infected calves showed increased levels (P<0.001) of lipid peroxidation (malondialdehyde; MDA, 52%) and protein oxidation (protein carbonyls; PCs, 132%) in erythrocyte membrane as well as increased values of Hb oxidation (methemoglobin; MetHb, 186%), corpuscular osmotic fragility (15.1%) and hemolysis (free Hb; 195.5%). Parasitemia was positively correlated with MDA (r=0.41, P=0.039), PCs (r=0.45, P=0.023) and MetHb (r=0.40, P=0.042). Also, percent of erythrocytic deformability (echinocytosis) was positively correlated with MDA (r=0.49, P=0.013) and PCs (r=0.63, P<0.001). On the other hand, erythrocytic packed cell volume was negatively correlated with MDA (r=-0.44, P=0.028), PCs (r=-0.72, P<0.001) and MetHb (r=-0.42, P=0.037). In conclusion, T. annulata infection is associated with a parasitic burden-dependant oxidative damage to the erythrocyte membrane protein and lipid contents in addition to Hb. This oxidative damage is linked to the morphological changes of the erythrocyte and may act as mechanisms contribute to pathogenesis of anemia in T. annulata infection in newborn calves.