Mapping the epidemiology and intensity of Parascaris equorum infection in equids in Erbil Province, Iraq

Abstract

This study investigated the prevalence, intensity, and associated risk factors of Parascaris equorum (P. equorum) infection in equids using both parasitological and molecular methods. Data on age, sex, body condition, and housing conditions were systematically collected to evaluate their influence on infection risk. Fecal samples from 294 equines (148 horses, 47 mules, 63 donkeys, and 36 ponies) were examined microscopically using direct wet-mount and flotation techniques, with infection intensity quantified using the McMaster technique to determine eggs per gram (EPG). Molecular confirmation was conducted via PCR targeting the ITS-2 region of P. equorum, followed by sequencing one PCR-positive sample per species and phylogenetic analysis using MEGA 7 software. The overall prevalence was 28.2 %, with the highest rates observed in donkeys (38.1 %), followed by horses (29.1 %), mules (23.4 %), and ponies (13.9 %). Higher infection rates were significantly associated with younger age, male sex, poor body condition, and outdoor housing. Infection intensity varied by species, with moderate infections more frequent in horses and severe cases predominant in donkeys. Phylogenetic analysis revealed high genetic similarity between local and international P. equorum isolates, indicating low genetic variability. These findings underscore the widespread presence of P. equorum in equids and highlight the importance of combining conventional and molecular diagnostics for effective detection and control. To mitigate infection and improve equine health, the study recommends implementing routine deworming schedules, enhancing stable hygiene and manure management, and providing targeted nutritional support, particularly for animals in poor body condition.