Toxocariasis is an infection caused by the Toxocara parasite, a type of parasitic roundworm. While the infection can affect people of all ages, children are more likely to contract the disease. According to the Centers for Disease Control and Prevention, approximately 14 percent of Americans have antibodies to the Toxocara roundworm, meaning they have been exposed to the parasite.

Here are some of the most commonly asked questions about the diagnosis, treatment, and prevention of toxocariasis.

  1. How is toxocariasis spread? Toxocariasis is a zoonotic disease, meaning that it can spread from animals to humans. Dogs and cats both carry strains of the Toxocara parasite and shed the parasite’s eggs in their feces. These eggs then become infectious after 10-21 days and can survive for many months in sand and soil. Humans can contract the infection when they come into contact with and accidentally ingest these eggs. Children are particularly susceptible to toxocariasis as they are more likely to play in contaminated dirt or sand and not properly wash their hands. In rare cases, the infection can also spread through undercooked meat containing Toxocara larvae.
    Toxocariasis cannot be spread from person to person like the common cold.
  2. What are the symptoms of toxocariasis? Many people who contract toxocariasis infections show no symptoms and do not ever actually get sick. For people who do develop symptoms, these symptoms can take two forms: ocular toxocariasis and visceral toxocariasis. Symptoms of ocular toxocariasis include vision loss, eye inflammation, and damage to the retina; these symptoms often occur in only one eye. With visceral toxocariasis, the infection spreads to major organs, such as the liver or intestines. Symptoms of visceral toxocariasis include fever, fatigue, coughing and wheezing, and abdominal pain.
  3. How is toxocariasis diagnosed? The symptoms of toxocariasis are similar to the symptoms of many other infections; thus, the condition can be hard to definitively diagnose. If you suspect that you or your child have become infected with toxocariasis, your doctor will most likely take a blood sample to detect the presence of Toxocaraanti bodies. You may also undergo an eye examination if you are experiencing ocular symptoms. Your doctor will also take a history of your symptoms and of any exposure you have had to dogs or cats.
  4. How is toxocariasis typically treated? Treatment for toxocariasis depends on which type you have contracted – ocular or visceral. Visceral toxocariasis is typically treated with antiparasitic drugs to kill the larvae in your system. Treatment of ocular toxocariasis is more difficult and will typically center on measures to try to prevent the progression of eye damage. Steroids will also sometimes be used to treat both types of toxocariasis in cases of more severe infection.
  5. How can I prevent toxocariasis infection? Proper personal hygiene and handwashing techniques are the best way to prevent toxocariasis in yourself and your children. Wash your hands thoroughly with warm soap and water after playing with or cleaning up after your pets, after outdoor activities (such as gardening or playing in sandboxes), and before and after handling raw food. In addition, clean up your pet’s living area (litter boxes, yards, etc.) regularly to dispose of feces. Do not let children play in areas where pets go to the bathroom, and keep sandboxes and other children’s play areas covered or fenced off to prevent animals from soiling these areas.
  6. What kinds of tests are used to test for toxocariasis? Blood samples are used to detect Toxocara antigens. The most common toxocariasis antigen test is an enzyme-linked immunosorbent assay (ELISA), like the IVD Toxocara Serum Antibody Detection Microwell ELISA.


Centers for Disease Control (CDC). “Parasites – Toxocariasis (also known as Roundworm Infection).” Available at

National Health Service (NHS). “Toxocariasis.” Available at