Toxocariasis is an infectious parasitic disease caused by the larvae of the nematodes Toxocara canis and Toxocara cati, which are worms inhabiting the intestines of their hosts. Toxocariasis is a worldwide infection and humans are incidental hosts in which aberrant infection occurs because the parasites cannot completely mature .
The usual mode of infection is eating contaminated soil (geophagia) via the hands, or uncooked food. Children who have close contact with dogs (puppies) are at great risk of infection.
The disease is typically unilateral and most often seen in children. Some cases in adults have been reported. Symptoms include decreased visual acuity but the initial clinical manifestation may be strabismus or leukocoria.
There are three main forms of ocular toxocariasis:
- Peripheral granuloma
- Posterior pole granuloma
- Chronic endophthalmitis