Distinguish the stool appearance of hookworm eggs from Strongyloides stercoralis larvae.

• A. Hookworm eggs are slender, oval eggs; Strongyloides typically presents rhabditiform larvae in stool.
• B. Hookworm eggs in stool; Strongyloides larvae are cysts in stool.
• C. Hookworm larvae are present in stool; Strongyloides eggs are present in stool.
• D. Hookworm eggs and Strongyloides eggs are indistinguishable in routine stool tests.

Answer: (A)

The main idea here is that the forms seen in stool differ between these two parasites, guiding how they’re identified under the microscope. Hookworms are diagnosed by finding eggs in the stool, and those eggs are slender and oval with a thin shell containing a developing embryo. Strongyloides stercoralis is typically diagnosed by finding rhabditiform larvae in the stool rather than eggs, because the eggs often hatch before being shed and the larvae become the recognizable form in routine stool exams. So the best description is that hookworm eggs are slender, oval eggs, while Strongyloides typically presents rhabditiform larvae in stool.

This fits because it highlights the key contrast—eggs for hookworms versus larvae for Strongyloides. The other statements misrepresent what is usually seen in stool (for example, Strongyloides cysts aren’t expected, hookworm isn’t typically identified by larvae in standard stool, and eggs and larvae are not indistinguishable).