What question did this study set out to answer?

The study aims to investigate gastrointestinal helminth infections in horses and associated risk factors in northern and northeastern Iran.

March 21, 2026Open Access

Epidemiological study and risk factors of equine (Equus ferus caballus) gastrointestinal helminth infections in the north and northeast of Iran

Key Points

The study aims to investigate gastrointestinal helminth infections in horses and associated risk factors in northern and northeastern Iran.
Examined 340 fecal specimens from horses in northern and northeastern Iran.
Used polymerase chain reaction (PCR) to identify S. westeri eggs.
Conducted coproculture on positive Strongyle samples to identify species.
Analyzed associations between infection rates and factors like feeding type and anthelminthic treatment.
Overall gastrointestinal helminth prevalence was 40.6%.
Northern horses showed a higher prevalence (55.3%) compared to northeastern horses (30.2%).
Strongylidae and Parascaris sp. were the most commonly identified helminths.
Free-grazing horses had a higher infection rate than stabled horses.
Horses receiving anthelminthic treatment had a lower infection rate.

Abstract

Understanding the epidemiology of gastrointestinal (GI) helminth infections in equines is critical for investigating drug resistance patterns and developing effective strategies to control and prevent these infections. There is a lack of data regarding horse GI helminths and risk factors in the north and northeast of Iran. Hence, the present study aimed to identify GI helminths in horses in these regions and determine their risk factors. A total of 340 fecal specimens from horses of north ( n = 141) and northeast ( n = 199) Iran were coprologically examined for GI helminth infections. The polymerase chain reaction (PCR) technique was used to detect Strongyloides westeri ( S. westeri ) eggs in horses. The prevalence of GI helminths in equines was 40.6%, with the highest prevalence reported in horses from the north of Iran at 55.3% (95% CI: 46.8–63.6), compared with 30.2% (95% CI: 23.9–36.9) in horses from northeast Iran. The recovered helminth parasite species were Strongylidae (27.9%; 95/340), Parascaris sp. (10%; 34/340), S. westeri (3.5%; 12/340), Oxyuris equi (1.2%; 4/340), Anoplocephala perfoliata (0.6%; 2/340), Trichuris spp. (0.3%; 1/340), and Dicrocoelium dendriticum (4.7%; 16/340). The coproculture performed on 95 positive Strongyle fecal samples revealed S. vulgaris at 67.4% (64/95), S. edentatus at 29.5% (28/95), Cyathostominae at 49.5% (47/95), and Trichostrongylus spp. at 5.3% (5/95). Furthermore, there was a significant association between GI parasite prevalence and feeding type, with free-grazing horses having a higher infection rate than stabled horses. Age was not significantly associated with the overall infection rate. However, only the Parascaris sp. infection was significantly higher in younger horses (Group A). Additionally, horses that received anthelminthic treatment had a lower infection rate than those without a history of anthelminthic treatment. The high prevalence of GI helminths in horses in the studied region underscores the need for strategic deworming, broad-spectrum anthelminthics, and a rotational grazing program to control and prevent infections.

Epidemiological study and risk factors of equine (Equus ferus caballus) gastrointestinal helminth infections in the north and northeast of Iran

Key Points

Abstract

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