Toxocariasis

Also called Toxocara infection or Roundworm infection

Toxocariasis is a rare infection caused by roundworm parasites found in the poo of infected dogs, cats and foxes. People can be infected by swallowing eggs from soil or sand, for example in parks or sandpits, or on unwashed hands. Young children are most at risk. It does not spread from person to person.

Last updated Nov 9, 2026

What it is

Many people have no symptoms. If symptoms do occur, medicines to kill the worms may be given.

Rarely, the larvae reach the eye and cause vision problems, which needs specialist treatment. Washing hands, worming pets and picking up dog poo help prevent it.

Common signs

  • Often no symptoms
  • A high temperature
  • A cough or wheezing
  • Tummy pain
  • An itchy rash
  • Eye pain, redness or blurred vision in eye infection

How it is usually diagnosed

  • Questions about contact with animals and soil
  • Blood tests
  • Eye examination

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Blood test results
  • Eye clinic letters
  • Prescriptions

Questions to ask your doctor

  • Could my eyes be affected?
  • Do I need treatment?
  • How can we stop it happening again?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • Sudden changes in vision, eye pain or a white pupil: get urgent help the same day

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

Sources