Which parasite is known for autoinfection?

Which parasite is known for autoinfection?

• A. Trichuris trichiura
• B. Strongyloides stercoralis
• C. Hookworms
• D. Ascaris lumbricoides

Answer: (B)

Autoinfection is when a parasite can complete part of its life cycle inside the same host, producing infective forms that reinfect without leaving the body. Strongyloides stercoralis does this through autoinfective larvae: the rhabditiform larvae in the gut can molt into filariform larvae within the host and penetrate the bowel wall or perianal skin to re-enter the circulation, allowing the infection to persist for years even without new exposure. This unique ability means Strongyloides can sustain infection internally and can become severe (hyperinfection) in immunocompromised individuals. The other parasites listed do not typically autoinfect; they rely on external development or different transmission routes, so they don’t sustain infection within the same host in this way.

Autoinfection is when a parasite can complete part of its life cycle inside the same host, producing infective forms that reinfect without leaving the body. Strongyloides stercoralis does this through autoinfective larvae: the rhabditiform larvae in the gut can molt into filariform larvae within the host and penetrate the bowel wall or perianal skin to re-enter the circulation, allowing the infection to persist for years even without new exposure. This unique ability means Strongyloides can sustain infection internally and can become severe (hyperinfection) in immunocompromised individuals. The other parasites listed do not typically autoinfect; they rely on external development or different transmission routes, so they don’t sustain infection within the same host in this way.