Equine Pinworm Life Cycle

Although they are not life-threatening, equine pinworms can be a nuisance to horses. They can also ruin a horse aesthetically as it scratches its tail area to relive the itching from a pinworm infection. Because pinworms are prolific breeders, it can be difficult to eradicate a pinworm infection.

  1. Pinworm

    • Adult equine pinworms are between 3 and 6 inches long. They live in the stomachs and intestinal tracts of horses.

    Eggs

    • The female lays eggs around the anus of an infected horse. The eggs then fall to the ground.

    Ingestion

    • Once on the ground, the eggs are ingested by other horses as they feed.

    Maturity

    • Once ingested, the egg rests in the stomach of the horse, where it hatches into a pinworm larvae. The larvae typically remain in the stomach, but might migrate to nearby organs.

    Reproduction

    • When the larvae have reached adulthood and are ready to reproduce, they make their way into the intestines of the horse and breed.

    Egg Laying

    • Once the female pinworm is ready to lay her eggs, she travels through the intestine to the anus. Upon reaching the anus she deposits her eggs and they cycle begins again.