Life Cycles of Nematodes, continued

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Life Cycles of Nematodes, continued

The life cycles of Enterobius vermicularis and Strongyloides spp. represent yet two more variations on the roundworm theme.
Some unique features of Strongyloides include:
  • It can undergo a complete life cycle in the soil (although ultimately, a host will be required).
  • It can complete a life cycle within the human host, which can lead to a hyperinfection.
  • The eggs hatch in the human intestine, meaning that diagnosis depends on finding larvae in the stool, not eggs.
Some unique features of Enterobius include:
  • Although the eggs can survive in the soil, a soil phase is not required, and infection can occur by ingesting eggs acquired directly from someone else.
  • The females migrate out of the colon into the perianal folds to deposit their eggs (usually occurs at night), so the best diagnostic method is by examining a piece of clear tape that was applied to the perianal folds (eggs can occasionally also be seen in the stool).
34. DPDx. "Strongyloidiasis - Life Cycle." CDC.gov, 30 Jul 2019, https://www.cdc.gov/dpdx/strongyloidiasis/index.html
35. DPDx. "Enterobiasis - Life Cycle." CDC.gov, 5 Aug 2019, https://www.cdc.gov/dpdx/enterobiasis/index.html

The Strongyloides life cycle (34).
The Enterobius life cycle (35).