Answer to Case 499

Answer: Strongyloides stercoralis adult female worm and larvae.

The video shows both an adult and the larvae:

Capillaria philippinensis can have a similar presentation to S. stercoralis, with both adults and larvae present in the intestine; however, Capillaria is an obligate parasite and would not likely survive in the viral culture media for very long. If in doubt, you could differentiate C. philippinensis adults and larvae by examining good wet preparations of this specimen. Capillaria adults have a prominent stichosome whereas Strongyloides adults do not. Also, Capillaria rhabditiform larvae do not have a prominent genital primordium and clavate eosphagus like Strongyloides does. Unfortunately the buccal cavity is not clearly seen, but it appears to be relatively short.