Molecular Identification of Cytochrome b Mutations in Buparvaquone-Unresponsive Theileria annulata Isolates from Khorasan-Razavi, Iran

Abstract

Introduction

The failure of conventional therapies for bovine theileriosis in Khorasan-Razavi province and other regions of Iran has led to significant economic losses and raised concerns about rural livestock sustainability and national food security. This study identified specific cytochrome b mutations in Theileria annulata isolates collected from cattle showing clinical unresponsiveness to buparvaquone treatment in the Khorasan-Razavi province of Iran.

Materials and Methods

Blood samples were collected, and parasite DNA was extracted and amplified via PCR using specific primers.

Results

Sequencing and subsequent BLAST analysis revealed two novel cytochrome b variants, OQ230576 and OQ230577, registered in the NCBI GenBank. These variants exhibited multiple non-synonymous mutations compared to sensitive reference strains from Iran (MH248139/1) and Ankara. The OQ230576 sequence demonstrated six to ten mutations, while OQ230577 exhibited eight to ten mutations, suggesting structural alterations linked to drug resistance.

Conclusions

These findings confirm the emergence and spread of resistant Theileria annulata strains in the studied regions. The progressive decline in treatment efficacy underscores the urgent need for alternative therapeutic approaches and more robust disease management strategies to safeguard livestock productivity and rural economies.