Molecular detection and assessment of risk factors for Theileria lestoquardi in sheep from Balochistan, Pakistan

Abstract

This study aimed to determine the molecular prevalence and associated risk factors of theileriosis in sheep from Balochistan, Pakistan. For this purpose, a total of 408 blood samples were collected from tick-infested sheep in three different zones of Balochistan (i.e., Quetta, Zhob, and Loralai). All the collected samples were analyzed using conventional microscopy techniques, polymerase chain reaction (PCR), 18S small subunit rRNA gene sequencing, and phylogenetic analysis. The results of the microscopy and PCR confirmed the highest prevalence of Theileria species in district Zhob (14.22% and 15.68%) followed by district Loralai (11.52% and 13.97%) and district Quetta (10.29% and 12.00%), respectively. In addition, the prevalence of T. lestoquardi was higher in female sheep (84.12%), followed by adult sheep (74.71%) and the Hernai breed of sheep (28.23%) in the studied area. Similarly, the prevalence of theileriosis was higher in the summer season (40.59%), followed by the spring, autumn, and winter seasons. However, numerous risk factors such as age, sex, area, season, and breeds of the sheep were not significantly correlated (P > 0.05) with the presence of T. lestoquardi, except tick abundance and feeding pattern of animals (P < 0.05). Furthermore, sequencing and phylogenetic analyses of the isolated T. lestoquardi displayed 99% sequence similarity with isolates from Germany, Egypt, Iraq, India, Iran, and Pakistan. Altogether these results showed that T. lestoquardi is the main species causing ovine theileriosis in Balochistan. As a result, large-scale studies are required to design practical control approaches to reduce the risk of theileriosis infection in Balochistan, Pakistan.

Keywords: 18S rRNA; Balochistan Pakistan; Molecular prevalence; Phylogeny; Risk factors; Sequencing; Sheep; T. lestoquardi.