A disease acquired by swallowing the ova (eggs) of a roundworm which lives in the intestine of cats (Toxocara cati) or dogs (Toxocara canis). In humans, the small larval worms produced by these ova migrate to various parts of the body, including the retina of the EYE, where they then die, producing a small GRANULOMA which in turn may produce allergic reactions. In the eye it may cause choroidoretinitis. It is said that 2 per cent of apparently healthy people in Britain have been infected in this way. A course of treatment with thiabendazole may be recommended.