An Iranian study that sought to discover if larval stages of the bot fly life cycle were tied to gastric ulcers in horses found no such link, but it did highlight the prevalence of stomach problems in horses.
Fereydon Rezazadeh and Yashar Gharehaghajlou, writing in the Iranian Journal of Veterinary Medicine, noted that gastric ulcers are among the most common ailments in racehorses. Colic, weight loss and poor performance are some of the clinical signs.
The pair, with the Faculty of Veterinary Medicine at the University of Tabriz, noted that the second and third larval stages of the Gasterophilus species of bot flies live in the stomach of the horse.
The pair set out in their study to determine if there were any links between the presence of gastric ulcers in rural horses and Gasterophilus larvae.
Twenty rural horses living near Tabriz were randomly selected for endoscopic investigation. Their gender, age, housing situation, feed type, colic history, hair coat condition, deworming history, and the presence of Gasterophilus larvae were all determined. The horses comprised 13 mares and seven males, with an average age of about nine.
The endoscopic observation showed that nine of the horses — that’s 45% — had gastric ulcers. All of the ulcers were in the upper non-glandular part of the stomach, the researchers reported.
Overall, four, or 20% of the horses, had Gasterophilus larvae present — all in animals with no deworming plan.
Rezazadeh and Gharehaghajlou found no association between the presence of bot fly larvae and the occurrence of gastric ulcers, although they proposed a further study with a larger sample size.
The researchers said the frequency of gastric ulcers in the non-glandular portion of the stomach of the horses used in the study was high, but there was no association found between the presence of Gasterophilus larvae and gastric ulcers.
Rezazadeh F. & Gharehaghajlou Y. (2020) Endoscopic Finding of Gastric Ulcer in Rural Horse and Relation with Gasterophilus spp. Iranian Journal of Veterinary Medicine, (14) 1. https://doi.org/10.22059/ijvm.2019.277457.1004975