November: Unwelcomed Guests

Jeremy recently returned to Vancouver Island from the interior of BC and was having a gastroscopy performed after experiencing a few episodes of mild colic. Given his under condition, travel history and colic episodes, gastric ulcers were suspected. However, during his gastroscope, he did not show evidence of gastric ulcers- instead he had several unwelcome guests, stomach bots, attached to the lining of his stomach. Botflies, Gasterophilus, are not very commonly seen here on Lower Vancouver Island as much as elsewhere in warmer climates. The life cycle involves female flies laying sticky eggs on the horses’ body hairs. Different species of Gasterophilus will lay eggs on different areas of the body. Horses will unintentionally ingest these eggs during grooming, the larvae will hatch out of the eggs in the mouth, burrow into the mucosa, be swallowed and attach to the stomach lining. In winter months they will normally detach from the stomach, pass through the feces, pupate and complete their life cycle. The best news for Jeremy and his owner was that his woes could be treated by deworming with ivermectin or moxidectin.