Concern about cases of pinworm (Oxyuris equi) has been on the increase over the last few years. If a pinworm problem is suspected then a worm count is unlikely to show the worm eggs because they are more often laid outside the horse around the anus area. Instead a more reliable sellotape test is used which takes an impression from the skin around the horse’s bottom. This is examined under the microscope to look for the presence of pinworm eggs.
Fortunately pinworm does not cause a problem to the horse’s digestive system and won’t cause internal damage like other worms. However it can cause irritation, sometimes so severe that horses will rub themselves raw around their tail head; this can lead to skin infections and further problems. Use this test on an adhoc basis to help detect a pinworm problem if a horse is itching its tail.