Introduction

Oxyuroidea

Introduction

Nematodes in the order Oxyurida are classified into two superfamilies. members of the Superfamily Oxyuroidea are found in vertebrates and the Thelastomatoidea in herbivorous arthropods such as cockroaches. The Oxyurida is the only significant group of nematodes with adult members in both vertebrates and invertebrates.

The only oxyurid of significance in domestic animals is Oxyuris equi found in the cecum and colon of horses. However, a number of species are of importance in humans and laboratory animals.

Species	Hosts	Predilection sites
Enterobius vermicularis	Humans & other primates (gibbons, chimpanzees & marmosets)	Cecum & appendix
Passalurus ambiguus	Rabbits & hares	Cecum & colon
Skrjabinema ovis	Sheep & goats	Colon
Syphacia obvelata	Mice(laboratory & wild)	Cecum
Aspiculuris tetraptera	Mice (laboratory & wild) & rats	Small & large intestines
Oxyuris equi	Horses & donkeys	Cecum & colon

Oxyuris equi

O. equi is found worldwide in horses and donkeys. The esophagus has a prominent posterior bulb. They are commonly called pinworms because of their pointed tails and the single pin-shaped spicule of males. Females are larger than males, measuring from 5 to 15 cm in length while males are approximately 1 cm long. The female vulva is situated anteriorly.

Oxyuris equi - male