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Review
. 2003 Apr;16(2):265-72.
doi: 10.1128/CMR.16.2.265-272.2003.

Toxocariasis: clinical aspects, epidemiology, medical ecology, and molecular aspects

Dickson Despommier  1
Affiliations
Review

Toxocariasis: clinical aspects, epidemiology, medical ecology, and molecular aspects

Dickson Despommier. Clin Microbiol Rev. 2003 Apr.

Abstract

Toxocariasis is caused by a series of related nematode species (ascarids) that routinely infect dogs and cats throughout the world. The eggs from these ascarids are common environmental contaminants of human habitation, due largely to the fact that many kinds of dogs and cats serve as pets, while countless others run wild throughout the streets of most urban centers. The eggs, present in dog and cat feces, become infectious within weeks after they are deposited in the local environment (e.g., sandboxes, city parks, and public beaches, etc.). Humans, particularly children, frequently ingest these eggs by accident and become infected. Infection in humans, in contrast to their definitive hosts, remains occult, often resulting in disease caused by the migrating larval stages. Visceral larva migrans (VLM) and ocular larva migrans (OLM) are two clinical manifestations that result in definable syndromes and present as serious health problems wherever they occur. Diagnosis and treatment of VLM and OLM are difficult. These issues are summarized in this review, with emphasis on the ecology of transmission and control of spread to both humans and animals through public health initiatives employing treatment of pets and environmental intervention strategies that limit the areas that dogs and cats are allowed within the confines of urban centers.

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Figures

FIG. 1.
FIG. 1.
Life cycle of T. canis and T. cati.
FIG. 2.
FIG. 2.
Portion of dog small intestine with adult T. canis. Male worms have a curled tail; females have a straight tail.
FIG. 3.
FIG. 3.
Unembryonated egg of T. canis (90 by 75 μm).
FIG. 4.
FIG. 4.
Embryonated egg of T. canis (90 by 75 μm).
FIG. 5.
FIG. 5.
Juvenile T. canis from impression smear of brain tissue from an experimentally infected mouse (390 by 30 μm).
FIG. 6.
FIG. 6.
Juvenile T. canis in liver of an experimentally infected mouse.
FIG. 7.
FIG. 7.
Portion of retina from a child suffering from OLM.
FIG. 8.
FIG. 8.
Portion of a retina from a child suffering from OLM. Note eosinophilic granulomatous lesion due to reaction against a dead juvenile worm.
See this image and copyright information in PMC

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