Zoonotic roundworm infections.

The larval stage of several animal parasites can infect humans and produce severe disease. Visceral and ocular larval migrans caused by the common dog roundworm, Toxocara canis, are two well-recognized clinical syndromes. With the wider availability of serodiagnostic tests for toxocaral infection, other syndromes characterized by neuropsychologic deficits, epilepsy, asthma, abdominal distress, and chronic allergy have been described. Treatment with corticosteroids in conjunction with anthelminthic drugs may be life- or sight-saving. Recognition of the risk factors for infection is key to prevention, reinfection, and more serious illness.