Vector identification and clinical, hematological, biochemical, and parasitological characteristics of camel (Camelus dromedarius) theileriosis in Egypt

The objectives of the present study were to identify a possible tick vector and to determine the prevalence of camel theileriosis in Egypt using blood smears stained with Giemsa's stain and PCR assay. Hemogram and serum biochemical constituents were also investigated. A total of 243 camels, aged 3-5 years, were examined. The results revealed that 75 (30.86 %) camels were infected with Theileria spp. of Giemsa-stained blood smears. Hyalomma dromedarii was identified as the carrier tick of Theileria spp. Multinucleated sporoblast and free sporozoite were observed in the salivary gland smears from collecting ticks. PCR result revealed that Theileria annulata was the most abundant in camels (60 %) followed by Theileria spp. (10 %). Macrocytic hypochromic anemia was recorded in the infected camels with T. annulata. Leukocytosis, neutrophilia, eosinophilia, and lymphopenia were also observed in the infected group. In the serum of infected camels, total proteins, albumin, beta-globulin, and A/G ratio were significantly decreased (P < 0.05); however, total globulins and alpha- and gamma-globulins were markedly increased (P < 0.05). The activity of aspartate aminotransferase and the levels of glucose, creatinine, and high-density lipoprotein cholesterol were markedly increased (P < 0.05) in the infected group. In contrast, triglycerides and total cholesterol concentrations were significant decreased (P < 0.001) in the infected group. In conclusion, a high prevalence of camel theileriosis was recorded in apparently healthy camels. H. dromedarii commonly infested these camels and were found infected with the transmissible forms of Theileria, indicating a role in transmission. Camels infected with T. annulata induced alterations in the cellular and biochemical constituents.