Nematode larva migrans

Abstract

Extract

The term larva migrans has been in use since the 1920s. Originally used to denote a cutaneous lesion caused by wandering hookworm larvae (Kirby-Smith et al., 1926; Heydon, 1929), more recently this term has been used for the lesions caused by larvae of Toxocara cards. To emphasize the more deep-seated migrations of the latter, Beaver et al. (1952) proposed the contrasting term “visceral larva migrans”. It was emphasized that, in both forms of larva migrans, the invading larvae are derived from nematode species which are not adapted to man and consequently remain immature and eventually perish. Beaver (1956) widened his definition of visceral larva migrans by including lesions caused by larvae of several other nematodes such as Capillaria hepatica, hookworms, Gnathostoma spp. and other spiruroids. He also included within the definition, as well as the abnormal man-nematode relationships, those in which man plays the role or paratenic host. Beaver's review was, and still is, the most comprehensive and authoritative account of larva migrans in man. It should be mentioned that the term larva migrans is also used for lesions caused by other parasites besides nematodes.