Toxocariasis (Visceral Larvae Migrans) (Hookworm)

Toxocariasis is a chronic infection caused primarily by the parasite Toxocara canis which is carried by dogs, but also by T. cati which is carried by cats. Humans contract the infection after ingestion of soil or food contaminated by toxocara eggs. The eggs hatch in the intestine and the larvae spread to other organs via the blood stream or lymphatic system.

Symptoms are due to the migration of the larvae to organs and include fever, cough, abdominal pain, swollen lymph glands and hives.

Where does it occur?

It occurs worldwide but is seen more commonly in rural areas of developing countries.

How is it transmitted?

It is transmitted by ingestion of toxocara eggs in soil contaminated by dog or cat feces either directly or indirectly by eating contaminated raw vegetables. They are found in high concentrations in the soil of animal parks and sand boxes.

Is it contagious from person to person?

It is not contagious from person to person.

What is the risk for travelers?

Risk for travelers is generally low.

How soon after exposure will one develop symptoms?

Symptoms usually develop weeks or months after ingestion.

What are the signs and symptoms?

Many present with fever, cough, and shortness of breath with wheezing due to the larvae migrating to the lungs. As the larvae migrate through the skin one develops red itchy lesions like hives. Involvement of the liver is common with enlargement causing abdominal pain.

Rarely involvement of the eye called ocular larvae migrans can be seen with decrease in vision and a mass in the eye. One can also experience seizures but this is uncommon.

Are there any lab tests to diagnose the illness?

One sees markedly elevated white blood cells and eosinophil counts. Specific antibody tests are available to establish the diagnosis.

Is there any treatment?

Antibiotics called albendazole or mebendazole are effective.

What preventive measures can be taken?

Wash hands after playing in soil contaminated by dog or cat feces. Pay attention that children do not eat soil and wash vegetables well prior to eating.

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