Toxocara canis.
Toxocara canis, commonly known as the dog ascrid, is a frequent parasite of the domestic dog. If the eggs of an adult worm are accidentally ingested by a human host, usually a child, a larval form of the worm develops that can survive for a limited period in various human tissues. The retina is one of these tissues and upon the death of this organism a granulomatous reaction occurs and a fibrotic mass is formed in the retina. This unusual ophthalmoscopic appearance is demonstrated by the presentation of three fundus photographs of patients with suspected Toxocara lesions. A knowledge of this parasite and its life cycle will aid in its recognition, treatment, and possible prevention.
D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005128:Eye Diseases / Q000469:parasitology*; D005654:Fundus Oculi; D006099:Granuloma / Q000469:parasitology; D006801:Humans; D007816:Larva Migrans, Visceral / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D012164:Retinal Diseases / Q000469:parasitology*