Cultivation, cryopreservation and resuscitation of Theileria annulata transformed cells in serum-free media

In vitro infection of bovine erythrocytes with Theileria annulata merozoites as a key step in completing the T. annulata life cycle in vitro

Theileria annulata is a protozoan parasite with a complex life cycle involving a bovine host and a tick vector. It is transmitted by Hyalomma ticks and is the causative agent of tropical theileriosis, a debilitating and often fatal disease in southern Europe, northern Africa and large parts of Asia. Understanding the biology of different life cycle stages is critical for the control of tropical theileriosis and requires the use of experimental animals which poses an ethical concern. We present for the first time the in vitro infection of red blood cells (RBCs) with T. annulata differentiated schizonts. The Ankara cell line of T. annulata was cultured at 41 °C for nine days to induce merogony and subsequently incubated with purified RBCs for one to three days. Percentage of parasitized erythrocyte (PPE) over the short culture period was estimated by Giemsa staining (0.007-0.01%), Flow cytometry activated sorting (FACS) (0.02-1.1%) and observation of FACS sorted cells by confocal microscopy (0.05-0.4%). There was a significant difference in the PPE between FACS and the two other techniques (one-way ANOVA followed by Tukey test, P = 0.004) but no significant difference was observed between the confocal imaging and Giemsa staining methods (ANOVA one-way followed by Tukey test, P = 0.06). Importantly, all three complementary methods confirmed the invasion of RBCs by T. annulata merozoites in vitro. Although the experimental conditions will require further optimization to increase the PPE, the in vitro infection of RBCs by T. annulata merozoites is pivotal in paving the way for the eventual completion of the T. annulata life cycle in vitro when combined with artificial tick feeding.

Molecular detection of Theileria spp. in native sheep and estimation of hemato-biochemical parameters from Sulaimani province/Iraq

Theileriosis, the hemoprotozoan infection, is an endemic condition in tropical and subtropical areas. In this study, conventional PCR analysis was applied to detect the natural infection of native sheep with theileriosis and estimate its effect on hemato-biochemical parameters. The study was carried out in five regions of Sulaimani province, northern Iraq. From May to October 2021, a total of 360 blood samples were collected randomly from the jugular vein of sheep belonging to 23 flocks with a history of tick infestations. After PCR for theileriosis, the hematobiochemical parameters were evaluated by an automatic analyzer using commercial kits. The PCR results represented that 71.7% of the examined sheep were infected with Theileria parasites. The highest prevalence rate (74.6%) was reported in Said Sadiq, and the lowest prevalence (69.5%) was from Bazian. The infection rates in Mawat, Qaradagh, and Sharazoor were 73.1, 70.3, and 71.8%, respectively. The hemogram data revealed a significant decrease in erythrocyte count, hemoglobin concentration, and hematocrit values. Erythrocyte indices also showed significant increases in MC, MCH, and MCHC levels, but no significant differences were detected between the counting of leukocytes, lymphocytes, and granulocytes. Biochemical analysis revealed a significant decrease in total protein, albumin, and creatinine levels with a significant increase in urea and AST levels in infected sheep with theileriosis. Alteration in hemato-biochemical parameters from infected animals can outline the impact of theileriosis on body metabolism and blood factors in naturally infected sheep.