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For further information, see CMDT Part 37-29: Toxocariasis
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Essentials of Diagnosis
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Principally seen in young children
Most infections are asymptomatic
Liver and lungs most commonly involved organs
Central nervous system (CNS) infection is rare
Ocular larva migrans is distinct syndrome that occurs in children older than is typical for visceral larva migrans
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General Considerations
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Caused by the dog roundworm Toxocara canis or by the cat roundworm Toxocara cati
Rarely, Baylisascaris procyonis, a roundworm of raccoons, causes visceral larva migrans in humans
Humans are infected after ingestion of eggs in material contaminated by dog or other feces
With T canis, infection is spread principally by puppies and lactating females, and the eggs must be on the ground for several weeks before they are infectious
After ingestion by humans, larvae migrate to various tissues but cannot complete their life cycle
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Most infections are asymptomatic
Cough, fever, wheezing
Hepatomegaly, splenomegaly
Lymphadenopathy
Pulmonary infiltrates
Eosinophilia
Involvement of the CNS can occur rarely, leading to eosinophilic meningitis and other abnormalities
Ocular larva migrans presents with
Manifestations of B procyonis infection, although rare, are typically similar but more severe than those with T canis
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Differential Diagnosis
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Acute HIV infection
Infectious mononucleosis
Lymphoma
Malaria
Ascariasis
Chagas disease
Retinoblastoma
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Blood tests may show eosinophilia in patient with hepatomegaly or other signs of disease
Serologic tests may be helpful
Enzyme-linked immunosorbent assay against a group of excreted antigens has shown good sensitivity and specificity
Molecular assays can identify specific pathogens
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Diagnostic Procedures
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Most patients recover without specific therapy
Antihelminthics or corticosteroids may be considered in severe cases
Although no drugs have been proved to be effective, the following have been used
Albendazole
Mebendazole
Diethylcarbamazine
Ivermectin
Albendazole (400 mg orally twice daily for 5 days) has been recommended as treatment of choice
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Disease in humans is best prevented by periodic treatment of puppies, kittens, and nursing dog and cat mothers, starting at 2 weeks postpartum, repeating at weekly intervals for 3 weeks and then every 6 months
Prevent defecation by dogs and cats in areas where children play
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