Pneumonia-like complications due to larval migration through the lungs are most associated with infection by which organism?

• A. Hookworm
• B. Schistosoma japonicum
• C. Strongyloides stercoralis
• D. Ascaris lumbricoides

Answer: (B)

Pneumonia-like symptoms from larval migration through the lungs occur because some nematode larvae travel via the bloodstream to the lungs, causing transient pneumonitis with eosinophilia. The classic organism associated with this pulmonary migration is Ascaris lumbricoides. As the larvae pass through the lungs, patients may develop cough, wheezing, chest discomfort, and transient infiltrates on imaging (Loeffler’s syndrome); after a short period, the larvae are swallowed back into the digestive tract and mature in the small intestine.

While hookworms and Strongyloides stercoralis can also cause similar lung-stage symptoms during their migration, the association is most strongly and conventionally linked to Ascaris lumbricoides. Schistosoma japonicum mainly causes hepatic and intestinal disease, with pulmonary involvement not classically tied to larval migration through the lungs.

So, the pneumonia-like pulmonary phase during larval migration is best linked to Ascaris lumbricoides.