Identification, molecular characterization and risk factors of Theileria infection among sheep: a first comprehensive report from North India

Abstract

The present study was aimed at the identification, molecular characterization, and risk factor assessment of Theileria infection among sheep of Haryana province, north India. A total of 402 blood samples were collected from three different climatic zones of Haryana from March 2020 to September 2021. Light microscopy of blood smears revealed Theileria spp. infection in 47.26% (n = 190), while 60.94% (n = 245) of blood samples were positive using nested PCR. Extensive molecular characterization of Theileria infection using four pairs of species-specific primers indicated the dominance of T. ovis (29.1%) followed by T. lestoquardi (12.69%), T. luwenshuni (5.97%) and T. annulata (1.49%). Mixed infection was detected in 11.69% of cases. Bidirectional sequencing and phylogeny further confirmed the presence of these four Theileria spp. in the investigated area under study. Hematology indicated a significant (p < 0.01) reduction in various haematological indices of animals infected with T. luwenshuni and T. lestoquardi compared to the healthy control group. Risk factors like age, sex, and zone were significantly associated with Theileria infection in sheep. The present investigation depicts the first comprehensive molecular report of ovine Theileria spp., which warrants further study to develop suitable control strategies against these haemoparasitic infections.

Keywords:

• Sheep
• Theileria
• PCR
• 18S rRNA
• Phylogeny
• Hematology
• Ticks

Acknowledgement

The authors express their sincere sense of gratitude to the Director of Research and Vice Chancellor, LUVAS, Hisar, for providing research facilities and financial support. The authors also wish to acknowledge all veterinarians and technicians for their support for sample collection and livestock owners who gave their consent to handle their animals.

Authors contribution

AN, BRM: Conceptualization, Methodology, Investigation, Data curation, supervision, writing the original draft. SV, BK, AG: Methodology, sampling, Data handling, Formal analysis, Writing, review & editing. SS, HS, SR, VK: Methodology, Sampling, Writing review and editing.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper

Data availability statement

All the relevant data used to support the findings of this study are included within the manuscript.

Additional information

Funding

The present investigation was financially supported by Lala Lajpat Rai University of Veterinary and Animal Sciences (LUVAS), Hisar under Self-financing scheme [SF-46].