Toxocara Larva Migrans now

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  • Division of Parasitic Diseases, Center for Infectious Diseases, Centers for Disease Control, Atlanta, Georgia

It has been nearly 4 decades since Paul Beaver and others first identified Toxocara larvae as the cause of a common disease in children. Our knowledge of the frequency and type of illness produced by Toxocara ssp. has increased greatly during this time. Although under-recognized and under-reported, toxocaral larva migran is now recognized as a widespread and common human infection. Among helminth infections in developed countries, it is perhaps second in frequency only to pinworm.

Potential etiologic agents of larva migrans syndromes include a wide range of zoonotic helminths. Toxocara canis and T. cati, the common ascarids of dogs and cats, are incriminated most frequently, at least in temperate climates. This is a result of many factors including the high frequency of pet ownership, the high prevalence of Toxocara species in dogs and cats, and the long persistence of infective Toxocara eggs in the environment.1-3

Widespread environmental contamination with Toxocara eggs, the attraction of children to the animals and their environment, and the play habits of children combine to facilitate human infection with Toxocara ssp.