Which statement about Strongyloides stercoralis is true?

Which statement about Strongyloides stercoralis is true?

• A. It is transmitted by ingestion of eggs
• B. It is primarily a tapeworm
• C. It can cause autoinfection
• D. It is a protozoan

Answer: (C)

Strongyloides stercoralis is notable for autoinfection, meaning it can complete part of its life cycle inside the same person and maintain infection without new exposure. After the skin is penetrated by infective larvae from soil, the parasite migrates through the bloodstream to the lungs, is coughed up, swallowed, and reaches the small intestine where it can produce larvae. While most larvae are excreted in stool, some rhabditiform larvae can molt into infective filariform larvae within the host and re-enter the body by penetrating the intestinal or perianal mucosa. This allows ongoing infection for years and explains why immunosuppressed individuals can develop hyperinfection. It’s not transmitted by ingestion of eggs, it’s a nematode (not a tapeworm), and it’s a helminth rather than a protozoan.

Strongyloides stercoralis is notable for autoinfection, meaning it can complete part of its life cycle inside the same person and maintain infection without new exposure. After the skin is penetrated by infective larvae from soil, the parasite migrates through the bloodstream to the lungs, is coughed up, swallowed, and reaches the small intestine where it can produce larvae. While most larvae are excreted in stool, some rhabditiform larvae can molt into infective filariform larvae within the host and re-enter the body by penetrating the intestinal or perianal mucosa. This allows ongoing infection for years and explains why immunosuppressed individuals can develop hyperinfection. It’s not transmitted by ingestion of eggs, it’s a nematode (not a tapeworm), and it’s a helminth rather than a protozoan.