ROLE OF HARD TICKS IN TRANSMISSION OF THEILERIA IN IMPORTED CAMELS

SAYED, GEHAN M.; NAGEIB, BASEM. R.; ARAFA1, MOHSEN, I.; MAHMOUD, WAFAA G.

doi:10.21608/avmj.2025.360233.1583

ROLE OF HARD TICKS IN TRANSMISSION OF THEILERIA IN IMPORTED CAMELS

Document Type : Research article

Authors

¹ Parasitology Department, Animal Health Research Institute (AHRI), Assiut Lab, Agriculture Research Center, Egypt

² Department of Parasitology, Faculty of Veterinary Medicine, New Valley University

10.21608/avmj.2025.360233.1583

Abstract

Theileriosis is one of the most prominent tick-borne haemoparasitic diseases affecting camels. Microscopic analysis of Giemsa-stained blood smears obtained from 100 tick-infested imported camels at Daraw quarantine, Aswan Gov., Egypt, showed 42% (42/100) were infected with Theileria sp. Moreover, infection rates significantly increased in autumn and spring (83% and 78%, respectively) compared to winter's 44%, while it notably declined during summer to 27%. Both erythrocytic and lymphocytic forms of Theileria sp. in the affected camels were described. The erythrocytic forms were identified as ring, rounded, and rod shapes, and macro and microschizonts were observed in lymphocytes. Four species of ticks were recognized throughout the monitoring period, all of which were molecularly confirmed to harbor Theileria sp. stages. Hyalomma dromedarii was the predominant tick species (90.1%), while other tick species present in small numbers were H. excavatum (4.9%), H. rufipes (2.5%) and Amblyomma variegatum (2.5%). Four distinct developmental stages were observed in the stained midgut smears of ticks: immature zygotes, early zygotes, developing kinete in zygote, and undifferentiated kinete. Additionally, the haemolymph revealed mature motile kinete, multinucleated rod-shaped vermicules and banana-shaped multinucleated vermicules. Multinucleated polymorphous sporoblasts were noted in the salivary gland smears. The accuracy of the microscopic detection of Theileria sp. in ticks was determined to be 90%, with specificity and sensitivity recorded at 87.5% and 100%, respectively. Overall, our results concluded that Hyalomma sp. and Amblyomma variegatum collected from imported camels were reservoirs of Theileria sp. Additionally, the present study confirmed the high prevalence of theileriosis in imported camels.

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