Background and Aim: Theileriosis, caused by tick-borne hemoprotozoans of the genus Theileria, severely impacts the economics of the livestock industry in most tropical and subtropical countries. The aim of the present study was to detect Theileria spp. in domesticated animals (camels, cows, sheep, and goats) using direct microscopy and to determine the infection rate in geographically distinct regions in the northern emirates of the UAE.

Materials and Methods: Blood samples (n = 536) were collected from clinically symptomatic and asymptomatic domesticated animals and subjected to Giemsa staining and examined microscopically for the identification of Theileria.

Results: Smears showed an overall rate of positivity for Theileria spp. in 325/536 (60.6%) animals. Different infection rates were recorded across the various animal groups in the different study areas (Middle region 215/386 [55.7%], East region 100/139 [71.9%]). Of the 11 goat samples collected from the North region, 10 (90%) were positive. Infection rates per animal group based on microscopy were as follows: camels, 3/35 (8.5%); cows, 19/36 (52.7%); goats, 200/303 (66%); and sheep, 103/162 (63.5%). Reverse transcription polymerase chain reaction confirmation of all microscopy-positive samples identified 23/325 (7.1%) results as false-positive.

Conclusion: This study clarified that Theileria spp. is present in the Middle (Sharjah, Umm Al Quwain, and Ajman), East, and North regions. This report also confirmed the use of direct microscopy with Giemsa-stained blood films as the method of choice for diagnosing acute infections. Further work is needed to molecularly determine the prevalence and species of Theileria spp. circulating in the different parts of the UAE.

Keywords: microscopic examination, Theileria, UAE.

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