Background: Theileria annulata is a blood parasite affecting ruminants. Hemolytic anemia, secondary hypoxia, and vasculitis are the most important features of tropical theileriosis.Objectives: Evaluation of electrocardiographic findings and changes in cardiovascular biochemical markers including cTnI concentrations in cattle naturally infected with theileriosis in the absence of acute cardiac failure.Animals: Ninety adult Holstein cattle (>1 year) with clinical and laboratory evidence of theileriosis and 30 healthy cattle served as controls.Methods: Case-control study in which blood samples were collected and randomized after clinical, hematologic, parasitologic examination and laboratory confirmation and electrocardiographic recording on all animals, serum cardiac troponin I (cTnI), aspartate aminotransferase (AST), and creatine kinase-MB (CK-MB) were evaluated.Results: Serum concentration of cTnI was significantly higher in cattle with theileriosis (mean: 0.028 ng/mL; range: 0.005-0.21 ng/mL; control mean: 0.011; range: <0.005-0.09 ng/mL; P = .003). There was significant correlation between serum level of cTnI and PCV (r = À0.257; P < .001) and also between cTnI and parasitemia (r = 0.515; P < .001). Mean serum activities of AST and CK-MB were 107 ± 46 and 301 ± 103 U/L in sick animals, which were significantly higher than healthy cattle (P = .002 and P = .041, respectively). There were no pathologic arrhythmias detected in sick animals.Conclusions and Clinical Importance: Theileriosis is a risk factor for elevation of cardiac biomarkers in naturally infected Holstein cattle. Severity of anemia and parasitemia might contribute to the pathophysiology of myocardial damage. The prognostic significance of increased serum cardiac troponin I concentrations in cattle with hemolytic anemia merits further investigation.

The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (β, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).

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