Evaluation of Theileria infection in cows vaccinated against Theileriosis in the Zaveh area, Khorasan Razavi province

Document Type : Short Communication

Authors

1 Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Iran

2 Department of Pathobilogy, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad

Abstract

Theileriosis is one of the important tick-borne diseases mainly caused by Theileria annulata in cattle. Tropical theileriosis causes a lot of economic losses in dairy farms due to decreased livestock production, emaciation, and death. To control the disease, it is necessary to vaccinate dairy cattle and apply acaricides against tick vectors regularly.
The Zaveh area, with a semi-arid climate, is located in Khorasan Razavi Province. The annual prevalence of bovine theileriosis is high in this area, which vaccinates many dairy cattle every year. The study aimed to determine the frequency of Theileria infection in vaccinated dairy cattle against T. annulata in the Zaveh area.
One hundred twenty vaccinated dairy cattle were selected from four dairy farms and then collected EDTA whole blood samples and thin blood smears. The blood smears were stained with Giemsa dye, and the EDTA blood samples' DNA was extracted with a commercial kit.
Out of 120 stained blood smears, 32 blood smears (26.66%) had piroplasms with low parasitemia. The PCR results showed no positive reaction in the blood DNA samples of vaccinated cattle. Any clinical signs of theileriosis were reported during the study.
In this investigation, although piroplasm forms exhibiting minimal parasitism were detected in the blood smears of multiple vaccinated cows, the PCR outcomes derived from Tams-1 gene amplification returned negative results. Given the significant polymorphism of this gene observed in the sequenced samples of Theilaria annulata, the occurrence of such results is not entirely dismissible, indicating the need for additional research.

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Veterinary Research & Biological Products
Volume 38, Issue 2
June 2025
Pages 62-68

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History

  • Receive Date: 10 August 2024
  • Revise Date: 19 January 2025
  • Accept Date: 21 January 2025

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