Enterobius vermicularis infection is caused by what type of organism?

• A. A Virus
• B. A Bacterium
• C. A Parasite
• D. A Fungus

Answer: (C)

Classification of infectious agents is the focus here. Enterobius vermicularis is a parasitic worm, a nematode, that lives in the human intestine and can cause enterobiasis. It is a multicellular parasite, not a virus (which is noncellular), not a bacterium (a single-celled prokaryote), and not a fungus (a different group of eukaryotes). This makes it the best answer because it’s clearly a parasitic organism rather than a viral, bacterial, or fungal pathogen. In children, pinworm infections are common and spread by ingestion of eggs, typically causing perianal itching at night.