Visceral larva migrans (VLM) is caused by worms (parasites) that are found in the intestines of dogs and cats. The dog parasite is called Toxocara canis and the cat parasite is called Toxocara cati.
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. This can be through eating fruit or vegetables that were in contact with infected soil and not washed thoroughly before eating. People can also become infected by eating raw liver of 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 with 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 can cause the following symptoms:
Contact your health care provider if you develop any of the following symptoms:
A full medical exam is needed to rule out visceral larva migrans. There are many conditions that cause similar symptoms.
Prevention includes deworming dogs and cats and preventing dogs and cats 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 as well after being outdoors or after touching cats or dogs.
Do not eat raw liver of chicken, lamb, or cow.
Despommier DD, Hotez PJ. Tissue nematodes. In: Long SL, ed. Principles and Practice of Pediatric Infectious Diseases. 4th ed. Philadelphia, PA: Elsevier Saunders; 2012: chap 277.
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. 7th ed. Philadelphia, PA: Elsevier Churchill-Livingstone; 2009:chap 291.
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.