Toxocariasis

Toxocariasis is a zoonosis caused by Toxocara canis (dog ascarid) or Toxocara cati (cat ascarid) larvae. Humans become infected by ingesting eggs or larvae from contaminated sources (soil, water, and raw food) or via fecal–oral transmission. Ocular toxocariasis, manifesting as ocular granuloma, was first described by Wilder (1950) in patients with endophthalmitis, Coats disease, or pseudoglioma. Six years later, Nichols found second-stage larvae of T. canis in histological sections from 24 of 46 enucleated eyes with suspected retinoblastoma (Nichols 1956). Human toxocariasis comprises two clinical entities: systemic toxocariasis (also termed visceral larva migrans) and ocular toxocariasis (also termed ocular larva migrans).