Answer to Case 560

Answer to Parasite Case of the Week 560: "Back to school" pinworm

This fun image had a question in 3 parts:

1. What is the parasite shown? Eggs of Enterobius vermicularis
2. Why is this a suitable parasite for September? September is the time that kids go back to school in America, and thus are more likely to obtain easily-transmitted parasites such as pinworm and head lice. As Nema noted, pinworm is "a parasite that is transmitted efficiently at the start of the school year because the embryonated eggs easily pass from the hands (unwashed) from one child to another and can also pass through the fomites"
3. What is the significance of the other objects in the picture? The backpack full of school supplies gives you the "back-to-school" link, whereas the tape refers to the cellulose tape method in which clear (not frosted!) tape is applied to the perianal skin folds to collect eggs (and occasionally adult females) that may be present. This test is commonly called the "Scotch" tape test in the U.S. after a common brand of tape; in the UK, it may be referred to as the Sellotape method - another common local brand.

In my lab, we prefer to use a plastic paddle with an adhesive surface to more efficiently and safely sample the perianal skin (a.k.a. the 'bum paddle' according to Marc). The paddle is easily transported to the lab inside the accompanying tube, and can then be examined directly under the microscope. The Graham test is another commercial collection method available in Europe.