Probstymayria vivipara

Prob·sty·may·ri·a vi·vip·a·ra

(prob'sti-mā'rē-ă vi-vip'ă-ră),
A nematode (family Atractidae) closely related to the true pinworms (family Oxyuridae) and still commonly considered the horse pinworm; it is distributed worldwide and is found often in tremendous numbers, because of internal autoreinfection, in the colon of horses and other equids.