Muhammad Haleem Tayyab1*, Muhammad Saqib1, Khurram Ashfaq1, Muhammad Sohail Sajid2
1Department of Clinical Medicine and Surgery, University of Agriculture, Faisalabad, Pakistan
2Department of Parasitology, University of Agriculture, Faisalabad, Pakistan
*Corresponding author’s email: muhammadhaleemtayyab381@gmail.com
Received: 21 June 2026 / Revised: 27 September 2026 / Accepted: 08 October 2026 / Published Online: 11 October 2026
Abstract
Equine piroplasmosis (EP), an important tick-borne protozoan disease primarily caused by Theileria equi and Babesia caballi, persists in healthy carrier horses, compromising equine health, performance and mobility. However, epidemiological data on EP in game horses in Pakistan are sparse. This study investigated the prevalence, geographical distribution, and epidemiological risk factors of T. equi, B. caballi, and mixed infection in game horses across Pakistan. We conducted a cross-sectional study with 430 horses from 23 districts of Punjab, Sindh, Khyber Pakhtunkhwa, and Gilgit-Baltistan from July 2020 to June 2021. Microscopic examination of blood samples was performed for the presence of piroplasms, and indirect enzyme-linked immunosorbent assays (iELISAs) of sera for antibodies against T. equi and B. caballi were conducted. We used prevalence estimates, chi-squared or Fisher’s exact tests, odds ratios, and exploratory multivariable logistic regression to analyze epidemiological and management data. Microscopic prevalence of T. equi and B. caballi infection was 26.51% and 0.23%, respectively. Seroprevalence of T. equi (33.95%), B. caballi (20.23%), and mixed seropositivity (14.88%), as determined by iELISA, was observed. Seroprevalence of T. equi differed significantly between provinces, ranging from 43.0% in Punjab to 4.5% in Gilgit-Baltistan. Older horses, especially those>10 years, had a higher likelihood of seropositivity. Prevalence was significantly higher in summer than in winter for both parasites. Ivermectin prophylaxis and acaricide use were associated with lower odds of seropositivity, while body condition score and multispecies farming were associated with variation in the odds of seropositivity. The results indicated a high prevalence of equine piroplasms in game horses across different geographical areas of Pakistan and also revealed significant seasonal, geographical, and management factors influencing infection. Furthermore, the differences between serological and microscopic findings reflect their distinct biological endpoints and highlight the value of complementary diagnostic approaches for assessing exposure and detecting parasitemia. Improving tick management, surveillance, and the strategic use of preventive measures, especially during peak transmission periods, could help reduce transmission and safeguard equine health in Pakistan. Results show there is high exposure to parasites in game horses and highlight the geographical, seasonal and management-related factors associated with seropositivity. However, the present study did not test for active transmission, carrier status, vector competence, or parasite maintenance, and further studies are needed to ascertain the role of game horses in the maintenance of national transmission.
Keywords: Equine piroplasmosis, Theileria equi, Babesia caballi, Game horses, Risk factors
