Most people infected with Toxocara do not have any symptoms. There are two major forms of toxocariasis, visceral toxocariasis (VT), also called visceral larva migrans (VLM), and ocular toxocariasis (OT), also called ocular larva migrans (OLM). The syndromes VLM and OLM can be caused by infection with the migrating larvae of other kinds of parasites which cause symptoms similar to those caused by migrating Toxocara larvae.
In a few people who are infected with high numbers of Toxocara larvae or have repeated infections, the larvae can travel through parts of the body such as the liver, lungs, or central nervous system and cause symptoms such as fever, coughing, enlarged liver or pneumonia. This form of toxocariasis is called visceral toxocariasis (VT). The larvae can also travel to the eye and cause ocular toxocariasis (OT). Ocular toxocariasis occurs when a microscopic Toxocara larva enters the eye and causes inflammation and scarring on the retina. OT typically occurs only in one eye and can cause irreversible vision loss.