Parasite
Strongyloides stercoralis
Threadworm with autoinfection cycle
stron-jih-LOY-deez ster-koh-RAL-iss
High-yield clue
Autoinfection lets it persist for years, and stool shows rhabditiform larvae (not eggs) - the defining teaching distinction.
Overview
An intestinal nematode capable of completing its cycle within a single host through autoinfection, the key concept that allows decades-long persistence and severe hyperinfection in immunocompromised study cases.
Classification
- Nematode (roundworm)
- Filariform larvae penetrate skin
- Rhabditiform larvae passed in stool
- Free-living and parasitic cycles
Lab & identification clues
- Rhabditiform larvae in stool (eggs rarely seen)
- Larvae distinguished from hookworm by short buccal cavity vocabulary
- Serology and repeated stool concentration concepts
Associations
- Filariform larvae penetrate skin from soil
- Autoinfection and hyperinfection syndrome vocabulary
- Risk with corticosteroids/immunosuppression
- Larva currens migratory rash association
Commonly confused with
- Hookworm (Ancylostoma/Necator)
- Enterobius vermicularis
Frequently asked questions
What is Strongyloides stercoralis?
An intestinal nematode capable of completing its cycle within a single host through autoinfection, the key concept that allows decades-long persistence and severe hyperinfection in immunocompromised study cases.
What are the lab clues for Strongyloides stercoralis?
Lab clues for Strongyloides stercoralis include Rhabditiform larvae in stool (eggs rarely seen), Larvae distinguished from hookworm by short buccal cavity vocabulary, and Serology and repeated stool concentration concepts.
What is Strongyloides stercoralis commonly confused with?
Strongyloides stercoralis is commonly confused with Hookworm (Ancylostoma/Necator) and Enterobius vermicularis.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.