Toxocara Canis

Excerpt

Human toxocariasis is a helminthic infection that primarily impacts populations of lower socioeconomic class in tropical and subtropical latitudes around the world. It is a roundworm (also known as nematode) that is not frequently clinically consequential; however, it is known to have severe complications such as blindness or meningoencephalitis.

Two main species of Toxocara affect humans: Toxocara canis and Toxocara cati. Definite hosts include cats, dogs, foxes, coyotes, and wolves. These hosts harbor the nematodes in their gut, shedding eggs in their feces. These embryonated eggs remain infectious for years outside the definitive host. In the wild, intermediate hosts such as other cats, dogs, rabbits, and fowl ingest the cysts, which hatch and migrate to various muscles and organs to encyst. In the wild, carnivorous animals such as cats and dogs consume infected meat (or simply soil containing the eggs), and the parasite remains in their gut. Additionally, there is solid documentation of transplacental transmission in dogs and cats. Humans are amongst a plethora of possible intermediate animal hosts. Clinical disease results from the migration of the parasite through extra-intestinal tissues.

Visceral larva migrans usually occurs in children because they often play in areas of contaminated soil.