Visceral larva migrans
Visceral larva migrans is a human infection with certain parasites found in the intestines of dogs and cats.
Toxocariasis; Ocular larva migrans; Larva migrans visceralis
Visceral larva migrans (VLM) is caused by roundworms (parasites) that are found in the intestines of dogs and cats.
Eggs produced by these worms are in the feces of the infected animals. The feces mix with soil. Humans can get sick if they accidentally eat soil that has the eggs in it. This can happen by eating fruit or vegetables that were in contact with infected soil and were not washed thoroughly before eating. People can also become infected by eating raw liver from a chicken, lamb, or cow.
Young children with pica are at high risk of getting VLM. Pica is a disorder involving eating inedible things such as dirt and paint. Most infections in the United States occur in children who play in areas, such as sandboxes, which contain soil contaminated by dog or cat feces.
After the worm eggs are swallowed, they break open in the intestine. The worms travel throughout the body to various organs, such as the lungs, liver, and eyes. They may also travel to the brain and heart.
Mild infections may not cause symptoms.
Serious infections may cause these symptoms:
If the eyes are infected, loss of vision and crossed eyes can occur.
Exams and Tests
If you have visceral larva migrans, you may have a high level of white blood cells.
People with this condition may also have signs of a:
- Swollen liver
- Lung or eye problem
Tests may include:
- Complete blood count with differential
- Blood tests to detect antibodies to Toxocara
This infection usually goes away on its own and may not require treatment. Some people need to take anti-parasitic drugs.
Severe infections involving the brain or heart can result in death, but this is rare.
These complications may occur from the infection:
- Worsened eyesight
- Encephalitis (infection of the brain)
- Heart rhythm problems
- Difficulty breathing
When to Contact a Medical Professional
Contact your health care provider if you develop any of these symptoms:
- Difficulty breathing
- Eye problems
A full medical exam is needed to rule out visceral larva migrans. Many conditions cause similar symptoms.
Prevention includes deworming dogs and cats and preventing them from defecating in public areas. Children should be kept away from areas where dogs and cats may defecate.
It is very important to wash your hands thoroughly after touching soil or after touching cats or dogs. Teach your children to wash their hands thoroughly after being outdoors or after touching cats or dogs.
DO NOT eat raw liver from a chicken, lamb, or cow.
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Diemert DJ. Tissue nematode infections. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 366.
Nash TE. Visceral larvae migrans and other unusual helminth infections. In: Mandell GL, Bennett JE, Dolan R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Churchill-Livingstone; 2014:chap 292.
Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.