Health Encyclopedia

Visceral larva migrans

Definition

Visceral larva migrans is an infection caused by certain parasites found in the intestines of dogs and cats. Persons who swallow dirt contaminated with dog or cat feces can catch the infection.

Alternative Names

Toxocariasis; Ocular larva migrans; Larva migrans visceralis

Causes, incidence, and risk factors

Visceral larva migrans is caused by worms (parasites) that infect the intestines of dogs and cats. The dog parasite is called Toxocara canis and the cat parasite is called Toxocara cati. Eggs produced by the worms are left in the feces of the animals. The feces mix with soil and dirt, allowing the infection to spread to humans. Humans may get sick if they eat unwashed raw vegetables that grew in the infected soil.

Young children with pica (eating inedible things such as dirt) are at highest risk, but this infection can also occur in adults. People can also become infected by eating raw liver.

After a person swallows the contaminated soil, the worm eggs break open in the gastrointestinal tract and are carried throughout the body to various places, such as the lungs, liver, and eyes. The brain, heart, and other organs can also be affected.

Symptoms

Mild infections may not cause symptoms.

More serious infections may cause the following symptoms:

Fever
Irritability
Abdominal pain
Itchy skin (hives)
Cough
Shortness of breath
Wheezing

If the eyes are infected, loss of vision and crossed eyes (strabismus) may occur.

Signs and tests

If you have visceral larva migrans, you may have a higher-than-normal level of white blood cells.

People with this condition may also have signs of a swollen liver, rash, and lung or eye problems.

A blood test can be done to detect and diagnose the infection.

Treatment

This infection usually goes away on its own and may not require treatment. However, some people may need anti-parasitic drugs, such as diethylcarbamazine, albendazole, or mebendazole.

Expectations (prognosis)

Mild infections may go away on their own. Severe infections involving the brain or heart can result in death, but this is rare.

Complications

Decreased visual acuity
Blindness
Respiratory distress
Heart arrhythmias
Encephalitis (infection of the brain)

Calling your health care provider

Contact your health care provider if any of the following symptoms develop:

Fever
Rash
Difficulty breathing
Cough
Eye problems

A full medical exam is needed to rule out visceral larva migrans. There are many conditions that may cause similar symptoms.

Prevention

Prevention includes de-worming of dogs and cats and keeping children away from areas where dogs and cats may use the bathroom. Carefully washing the hands after touching dirt and soil is very important.

Review Date:10/9/2006
Reviewed By:D. Scott Smith, M.D., MSc, DTM&H, Chief of Infectious Disease & Geographic Medicine, Kaiser Redwood City, CA & Adjunct Assistant Professor, Stanford University. Review provided by VeriMed Healthcare Network.

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