Which trophozoite shows two prominent nuclei and is identified as Giardia lamblia?

Which trophozoite shows two prominent nuclei and is identified as Giardia lamblia?

• A. Trichomonas hominis
• B. Chilomastix mesnili
• C. Giardia lamblia
• D. Trichomonas tenax

Answer: (C)

The key feature being tested is the binucleate trophozoite of Giardia lamblia. Giardia trophozoites are distinctive because they have two nuclei per cell, often giving a “double eyes” appearance under the microscope. This binucleate form, along with multiple flagella and a ventral adhesive disc, is characteristic of Giardia and helps distinguish it from other intestinal protozoa. For example, Trichomonas species typically have a single nucleus, and Chilomastix mesnili trophozoites also show a single nucleus and a different cytoskeletal setup. So, when you see a trophozoite with two prominent nuclei, Giardia lamblia is the most likely identification.

The key feature being tested is the binucleate trophozoite of Giardia lamblia. Giardia trophozoites are distinctive because they have two nuclei per cell, often giving a “double eyes” appearance under the microscope. This binucleate form, along with multiple flagella and a ventral adhesive disc, is characteristic of Giardia and helps distinguish it from other intestinal protozoa. For example, Trichomonas species typically have a single nucleus, and Chilomastix mesnili trophozoites also show a single nucleus and a different cytoskeletal setup. So, when you see a trophozoite with two prominent nuclei, Giardia lamblia is the most likely identification.