August 23, 2016
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Pinworm Test (cont.)

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Aside from the anal region, what other area can be tested for pinworms?

Samples taken from under the fingernails may also contain eggs (since scratching of the anal area is common).

Can I see the pinworms myself?

At night, the adult worms can sometimes be seen directly on the bedclothes or around the anal area. The best time for observation is at night when itching in the anal/rectal area awakens a person; it is likely the sensation caused by migrating female worms depositing eggs and irritating the skin (see the following section).

What do pinworms look like?

The pinworms are white, can be seen with the naked eye (no magnification) and are about the length of a staple (about 8-13 mm for female and 2-5mm for male worms). The eggs that are laid by the female worms are not visible as they are about 55 micrometers in diameter and are translucent (see Figure 1).

The male and female worms live for the most part within the rectum of humans but have a life cycle in humans that involves rectal/oral transmission (see Figure 2).

While an infected person is asleep, female pinworms leave the intestines through the anus and deposit eggs on the skin around the anus. This causes itching and irritation of the surrounding area; children especially will scratch the rectal/anal area, get eggs on their fingers or underneath their fingernails and transport the infective eggs to bedding, toys, other humans, or back to themselves. The eggs hatch into larval forms in the small intestines and then progress to the large intestine where they mature, mate, and progress to the rectal/anal area where females deposit about 10 to 15 thousand eggs.

Picture of pinworm and pinworm eggs (magnified)
Picture of pinworm and pinworm eggs (magnified). Source:
Medically Reviewed by a Doctor on 6/3/2015


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