Toxocariasis: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Toxocariasis?
A primary care doctor usually handles the first steps, ordering tests and starting treatment. Eye involvement requires referral to an ophthalmologist, and sometimes an infectious disease doctor helps guide treatment. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Toxocariasis is an infection caused by roundworms that live in the intestines of dogs and cats. Their eggs pass into soil through animal droppings, and people, especially children, can swallow them from dirty hands, toys, or contaminated food. The eggs hatch, and young worms travel through the blood to organs like the liver, lungs, eyes, or brain, causing swelling and damage.
Symptoms
There are two main forms. Visceral toxocariasis affects the internal organs, causing fever, tiredness, belly pain, coughing, wheezing, and an enlarged liver, though some people have no symptoms. Ocular toxocariasis affects the eyes, causing blurry vision, eye pain, light sensitivity, or vision loss in one eye, and the damage can be permanent if untreated.
Causes and who gets it
People get toxocariasis by swallowing roundworm eggs from infected dogs or cats. Puppies and kittens pass large numbers of eggs that can survive in soil and sandboxes for years. Children who play in dirt, pet owners, and people who eat raw or undercooked meat face higher risk. Washing hands after handling pets lowers the chance of infection.
How doctors diagnose it
Doctors often start with a blood test for antibodies, proteins the immune system makes to fight the worms. A positive test shows exposure but does not always mean active sickness. Doctors also consider symptoms, pet history, and soil contact. Eye involvement may require an eye exam or scans such as ultrasound or MRI.
Treatment
Treatment depends on the affected body part and how sick the person is. When needed, doctors use worm-killing medicines, sometimes with steroids to reduce swelling. Eye infections are treated by a specialist with oral medicines or injections near the eye. Existing damage, especially in the eye, may not fully heal.
When to see a doctor
Anyone with persistent fever, belly pain, cough, or wheezing should talk to a doctor, especially with pets or soil exposure. Vision changes, eye pain, or a dark spot in vision need prompt attention. Early care can prevent some damage.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can order tests, prescribe medicines, and provide frequent follow-up, referring to specialists when needed.
Common questions
Can toxocariasis spread from person to person?
No. The worms cannot pass directly between people. Infection only happens when someone swallows the eggs from soil, sand, or contaminated food.
Can my pet give me toxocariasis?
Yes, but only through the worm eggs in the pet's droppings that end up in soil or on fur and hands. Regular deworming of pets greatly lowers the risk. Deworming means giving pets medicine that kills worms.
Does toxocariasis go away on its own?
Mild cases often get better without medicine because the worms eventually die in the human body. More serious cases, especially those affecting the eyes, need treatment to prevent lasting damage.
How can I prevent toxocariasis?
Wash your hands after touching pets, soil, or sand, and teach children to do the same. Keep sandboxes covered, deworm pets regularly, and wash fruits and vegetables grown in gardens.
Sources
- NIH Genetic and Rare Diseases Information Center - Toxocariasis
- Centers for Disease Control and Prevention - About Toxocariasis | Toxocariasis
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
