Toxocariasis is a disease caused by larvae of two species of which roundworms?

• A. Ascaris lumbricoides
• B. Toxocara canis and Toxocara cati
• C. Ancylostoma duodenale
• D. Trichuris trichiura

Answer: (B)

Toxocariasis is caused by the larvae of two dog and cat roundworms, Toxocara canis and Toxocara cati. Humans become accidental hosts after ingesting embryonated eggs from soil contaminated with dog or cat feces. The larvae then migrate through body tissues, often first through the liver and lungs, and can reach the eyes or central nervous system, causing conditions like visceral larva migrans or ocular larva migrans. This stands in contrast to infections caused by Ascaris lumbricoides (ascariasis), or by hookworms like Ancylostoma duodenale and whipworms like Trichuris trichiura, which are different parasites and cause other diseases.