Theleiriosis in sheep is an important infectious disease of small ruminants characterized by General weakness, weight loss, anorexia, elevated body temperature, petechial hemorrhages on conjunctival mucosa, swollen lymph nodes, anemia and cough. Changes in hematological, serum biochemical and histopathological parameters are good indicators for diagnosis of theileriosis. For this purpose a total of 100 blood samples from infected sheep as well as 50 blood samples from healthy sheep were collected on the basis of clinical examination and peripheral blood smears from different farms in and around Lahore. The collected samples were processed at Clinical Pathology Laboratory, Department of Pathology, University of Veterinary & Animal Sciences, Lahore. Hematological parameters were measured by automatic hematology analyzer & serum biochemical parameters were measured by using commercial kits by colorimetric methods using spectrophotometer. Histopathological changes were observed by making slides of tissue samples, and observed under microscope. Molecular confirmation of Theleria sp. was done by using Polymerase Chain Reaction. Finally the data obtained for hematological and serum biochemical parameters were analyzed by using Student's t test.
Previous studies on serum biochemical parameters and hematological parameters were mostly done in large ruminants. But there is little investigation available on the biochemical and hematological alterations of theileriosis in small ruminants. In this study blood samples taken from sheep were examined under microscope by making thin blood smears using Giemsa stain. Theileria piroplasms were seen in RBCs at 100x. Blood samples were also processed for PCR test. In all Theileria ovis positive samples 520-bp fragment was generated on gel by using primers TSsr 170F and TSsr 670R for sheep. All samples positive on microscopy were also positive by PCR. This study provides the base line data for molecular diagnosis of Theileria ovis in sheep in Pakistan. Hematological and biochemical parameters were evaluated in the sheep naturally infected with theileriosis while healthy sheep were selected as control. Hematological findings revealed a significant decrease (P<0.05) in RBC count, WBC count, Hb Conc. and PCV in infected animals as compared with healthy animals. Serum biochemical findings also revealed alterations in activities of enzymes and plasma proteins. A significant decrease in total proteins, albumin, glucose and creatinin and triglycerides was observed while significant increase (P<0.05) in ALT, AST, bilirubin was observed in affected animals as compared with healthy animals. A non significant increase in urea and cholesterol concentration was also observed in infected animals as compared to healthy animals. Different tissues were examined to study gross and histopathological changes. Liver was large, pale and friable. Prescapular lymph nodes were swollen and spleenomegaly was also seen. Kidney showed hemorrhagic spots and some were mottled. Histological examination of the lymph nodes revealed edema, widened intercellular spaces, parenchyma degeneration, massive lympholysis, widened sinuses at some areas and macrophages. Splenic nodules were sparse, diminished in size and lymphocyte depletion in follicles was prominent.In liver, mild infiltration of leukocytes around blood vessels, vacuolation in hepatocytes, increase in sinusoidal space and atrophy of hepatic cord was seen and hepatic cord was broken. In kidney, degeneration of tubular epithelium cells was seen. This study concluded that theileriosis in sheep was associated with some alterations in blood parameters and histopathological changes which could be useful in the diagnosis of ovine theileriosis.