Molecular epidemiology, associated risk factors, and phylogeny of Theileria annulata infecting buffaloes and cattle from different agro-climatic regions of Punjab, Pakistan.

Background: Tropical theileriosis is the most prevalent hemoprotozoan disease in Pakistan.

Aims: The study aimed to investigate the epidemiology and evolutionary relationship of Theileria annulata in bovines in diverse agro-climatic regions of Punjab, Pakistan.

Methods: 800 blood specimens were collected from asymptomatic cattle (n=480) and buffaloes (n=320) using a multistage sampling method from Sargodha (n=400) and Multan (n=400) districts. The samples were assessed for blood smear microscopy and cytochrome b gene based PCR. Twenty samples were collected from each union council of each district.

Results: The overall prevalence of T. annulata infection in bovines was 9% and 17.13% as determined by blood smear analysis and PCR, respectively. The disease positivity in cattle and buffaloes was respectively 10.21% and 20.42% by blood smear screening and 7.19%, 12.19% by PCR. The overall PCR based prevalence in the Sargodha and Multan districts was 19% and 15.25%, respectively. Absence of rural poultry, tick infestation, and a history of tick-borne diseases had significant effect in cattle. Tick infestation and age were the main statistically significant disease determinants in buffaloes. The evolutionary analysis of the cytochrome b gene showed that the Pakistani isolate infecting buffalo was related to those from Iran, India, Egypt, and Sudan. The isolate from cattle was genetically close to those from Pakistan, India, Iran, Iraq, and Turkey.

Conclusion: It can be concluded that biotic and abiotic factors contribute to disease occurrence. The current study will help to devise control strategies to prevent substantial economic losses.