What is the primary diagnostic stage for Strongyloides stercoralis?

What is the primary diagnostic stage for Strongyloides stercoralis?

• A. Adult female in duodenal aspirate
• B. Egg in stool specimen
• C. Rhabditiform larva in stool specimen
• D. Filariform larva in stool specimen or sputum

Answer: (C)

The main diagnostic stage for Strongyloides stercoralis is the rhabditiform larva in stool. In infection, adult females live in the small intestine and lay eggs that hatch into rhabditiform larvae within the gut; these larvae are then shed in the stool and can be identified microscopically. Eggs are not typically seen in stool because they hatch before excretion, and while the infective stage is the filariform larva (which can appear in stool or sputum in disseminated disease), the routine, primary diagnostic finding is the rhabditiform larva. Seeing rhabditiform larvae in stool is the most common and reliable way to diagnose Strongyloides infection.

The main diagnostic stage for Strongyloides stercoralis is the rhabditiform larva in stool. In infection, adult females live in the small intestine and lay eggs that hatch into rhabditiform larvae within the gut; these larvae are then shed in the stool and can be identified microscopically. Eggs are not typically seen in stool because they hatch before excretion, and while the infective stage is the filariform larva (which can appear in stool or sputum in disseminated disease), the routine, primary diagnostic finding is the rhabditiform larva. Seeing rhabditiform larvae in stool is the most common and reliable way to diagnose Strongyloides infection.