Peste des petits ruminant (PPR) is a highly contagious and economically important disease of small ruminants. Plasma sialic acid is a marker of the acute phase response in pathological conditions and significant alterations within total sialic acid serum (TSA) concentrations have been documented in various diseases. The purpose of the study was to investigate changes in TSA serum concentrations in sheep suffering from peste des petits ruminants. Eighty sheep sera were tested for antibodies against PPRV with c-ELISA and 22 of the 80 sera (27.5%) were found to be positive. Twenty two sheep naturally infected by PPRV aged between 1-2 years old were categorized as the infected group and 16 clinically healthy sheep of the same age constituted the control group. Venous blood was sampled from the sheep's jugular veins. The concentration of TSA serum was measured by Warren's thiobarbituric acid assay. Clinical, hematological and biochemical changes, including liver function tests, were also evaluated. Higher concentrations of TSA serum were found in the infected sheep (84.7 +/- 13.1 mg/dL) compared to the healthy sheep (63.5 +/- 4.7 mg/dL), (P <= 0.001). In addition, significant correlations were determined between TSA and clinical symptoms, hematological changes and liver function tests of the infected sheep. The findings of the study indicate that TSA plays a part in the disease processes of PPR and that determining TSA serum concentrations may be used as a supplementary laboratory test in conjunction with clinical and laboratory findings when evaluating the prognosis of PPR.