Enterobius vermicularis
is the metazoan that causes pinworm infection. Symptoms may ensue when ova are ingested from hands or other fomites. The ova then mature into adults in the host's intestines. In the early morning hours, the female adult crawls out of the intestine to lay her eggs (ova) on the perianal region. Diagnosis depends on finding these ova via the Graham's Scotch tape method. In this procedure sticky cellophane tape applied to the anal area of the patient collects ova, which are then pressed to a microscopic slide and viewed. The presence of the characteristic flattened ovals is diagnostic for pinworm infection. Because the adult is cylindrically shaped, Enterobius is in the phylum Aschelminthes and the class Nematoda (roundworms). Enterobius is dioecious (having separate males and females).
Click on each image to see the enlarged version.
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| 1. female adult 8X | 2. female adult 40 X | 3. ova 400 X | 4. ova 400 X | 5. ova 400 X |
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| 6. ova 400 X | 7. ova 400 X | 8. ova 1000 X | 9. ova 1000 X | 10. ova 1000 X |
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