Which disease is specifically associated with larvae of Toxocara and can affect humans?

• A. Toxocariasis
• B. Ascariasis
• C. Hookworm disease
• D. Strongyloidiasis

Answer: (A)

Toxocariasis is caused when humans encounter Toxocara larvae, typically by ingesting eggs from soil contaminated with dog or cat feces. In people, these larvae don’t mature into adult worms in the gut; instead they hatch and migrate through tissues, provoking inflammatory reactions. This tissue migration can produce different clinical forms, most notably visceral larva migrans when larvae travel through organs like the liver and lungs, and ocular larva migrans when they affect the eye. The disease is classically associated with the larval stage of Toxocara and with incidental human infection, especially in children who play in contaminated soil. Diagnosis often relies on serology rather than stool testing, since the worms do not establish a typical intestinal infection in humans. Treatment with antiparasitics such as albendazole or mebendazole is common, and steroids may be used if significant inflammatory symptoms occur.

The other diseases are caused by different parasites and involve different life cycles. Ascariasis involves Ascaris lumbricoides and is primarily about intestinal adult worms with some larval migration, not a tissue-larval picture tied to Toxocara. Hookworm disease is due to hookworms like Necator and Ancylostoma, typically entering via the skin and affecting the small intestine. Strongyloidiasis arises from Strongyloides stercoralis and is notable for autoinfection; these conditions do not revolve around Toxocara larvae in humans.