Oxyuris

Oxyuris is a genus of nematode worms belonging to the family Oxyuridae. These are commonly known as pinworms or threadworms. The most well-known species is Oxyuris equi, which infects horses. Adult Oxyuris equi reside in the large intestine and cecum of their host. Females migrate to the perianal region to lay eggs, often causing irritation and itching, which can lead to tail rubbing in horses. The eggs are laid in a sticky gelatinous substance, which adheres to the hairs around the anus.

Diagnosis of Oxyuris equi infection is typically made by identifying the characteristic eggs or adult worms. Eggs are often found on cellophane tape prepped on the perianal area. The life cycle is direct, meaning that infection occurs when the horse ingests infective eggs from the environment. Horses can become infected by grooming themselves and ingesting eggs from contaminated surfaces or by ingesting contaminated feed or water.

While Oxyuris equi primarily affects horses, other species of Oxyuris can infect other equids like donkeys and zebras. The clinical signs are mainly related to the itching and discomfort caused by egg-laying, which can result in hair loss on the tail and hindquarters. In severe cases, secondary bacterial infections can occur due to excoriation of the skin. Treatment usually involves anthelmintic medications. Prevention strategies focus on good hygiene practices, including regular cleaning of stables and equipment to reduce environmental contamination.