This study was conducted to assess the pattern of changes and the relative value of acute phase proteins (haptoglobin (Hp), serum amyloid A (SAA), ceruloplasmin and fibrinogen) in bovine tropical theileriosis. The diseased group comprised 50 dairy Holstein cattle, 2-3 years old, naturally infected with Theileria annulata. Infected animals were divided into four subgroups with different parasitemia rates (<1%, 1-3%, 3-5%, >5%). As a control group, 20 uninfected cattle were also sampled. Blood samples were collected and all measurements were done using validated methods. There were significant differences in red blood cells (RBCs), packed cell volume (PCV), hemoglobin (Hb) and concentrations of Hp, SAA, ceruloplasmin and fibrinogen between healthy cattle and those infected with T. annulata with different parasitemia rates (P < 0.05). As the parasitemia rate increased in infected cattle, a significant decrease was observed in RBCs, PCV, and Hb. In contrast, with increase in the parasitemia rate, a significant increase in the mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), Hp, SAA, ceruloplasmin, and fibrinogen was evident. The optimal cut-off point was set by the receiver operating characteristics (ROC) method to >5.68 microg/ml for SAA, >0.16 g/l for Hp, >0.064 g/l for ceruloplasmin and >4.00 g/l for fibrinogen with corresponding 84% sensitivity and 100% specificity for SAA, 76% sensitivity and 100% specificity for Hp, 84% sensitivity and 80% specificity for ceruloplasmin and 40% sensitivity and 100% specificity for fibrinogen. SAA had the highest sensitivity and specificity and was diagnosed to be a suitable indicator of APPs changes in bovine theileriosis.
