Viscera larval migrans

Visceral larva migrans is a condition in children caused by the migratory larvae of nematodes like Toxocara vitulloram, Toxocara canis etc.

Since they can't reproduce in humans, they wander throughout the body, invading the heart (causing myocarditis) and the CNS (causing seizures). They may also enter the eye, termed Ocular Larvae Migrans, sometimes resulting in the misdiagnosis of retinoblastoma.