Impact of Theileria annulata on Hemato-biochemical and Histological Parameters in Cattle

Background: Theileria Spp. is the causative agent of the economically significant hemoprotozoan disease known as theileriosis in cattle. In dairy animals, it results in death and decreased productivity. This study aimed to clarify the effects of Theileria annulata (T. annulata) infection on the histological and haemato-biochemical parameters in infected cattle. Methods: Between December 2022 and May 2023, 200 cattle were randomly selected from the slaughterhouse and blood samples were collected from them to assess the hemato-biochemical parameters and screen for T. annulata infection using a Giemsa-stained blood smear, furthermore, the histological profile of the spleen, lymph nodes and liver. Result: T. annulata was detected in 26.5% of the cattle based on blood smear microscopy. The haematological analysis showed a notable increase in lymphocytes and a significant drop in platelets, haemoglobin, total leukocyte count and total erythrocyte count. In cattle infected with T. annulata, biochemical examination showed a significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), high density lipoprotein (HDL) and triglyceride, also increase in bilirubin. Histological examination revealed necrotic degenerations of splenic nodules, oedema, parenchymal necrotic degeneration, increased intercellular spaces, depletion of lymphocytes, increased sinuses in lymph nodes and focal necrosis of hepatocytes with infiltration of inflammatory cells and vacuolar degeneration of hepatocytes.