Worms in Children: Prevention and Deworming

Intestinal worms are one of the most common infections in children worldwide, and one of the most preventable. They rarely make a child dramatically ill on any single day. Instead they quietly take away nutrition, energy and growth.

Which worms are we talking about?

The main ones are roundworm, whipworm and hookworm. Together they are called soil-transmitted helminths, because they spread through soil contaminated with human faeces. WHO estimates about 1.5 billion people are infected worldwide, around 24% of the world's population, including roughly 260 million preschool children and 654 million school-age children.

How do children get them?

The worms lay eggs, which pass out in the faeces of an infected person. If human waste reaches soil or water, the eggs spread. Children then get infected by:

• Eating vegetables or fruit that were not washed, peeled or cooked, when they carry eggs from contaminated soil.
• Drinking contaminated water.
• Playing in soil and then putting unwashed hands in their mouths. This is the commonest route in young children.
• Walking barefoot on contaminated soil. Hookworm larvae can go straight through the skin of the feet.

Worms do not spread directly from one child to another, so the way to stop them is to break the soil, water and hand route.

What do worms do to a child?

Light infections often cause no symptoms at all. Heavier infections cause diarrhoea, stomach pain, feeling generally unwell and weakness. Over time they cause nutritional and physical harm:

• Iron-deficiency anaemia, especially from hookworm, which causes blood loss in the gut. Girls and women are particularly affected.
• Impaired growth and physical development. The CDC notes heavy infections can slow both physical and mental development in infants and children.
• Loss of protein and other nutrients the child needs.

For pregnant and breastfeeding women, worms add to the risk for both mother and baby. WHO counts nearly 139 million pregnant and lactating women among those at risk.

How do you prevent worms at home?

• Wash hands with soap before handling or eating food, and after using the toilet or playing outside.
• Wash, peel or cook raw fruit and vegetables before eating.
• Use safe drinking water, and avoid water that may be contaminated.
• Put shoes on children before they walk on soil that might be contaminated with human faeces.
• Use a proper toilet, and never let children pass stool in the open.
• Do not use untreated human waste as fertiliser on food crops.
• Trim children's nails short, so less soil is trapped under them.

WHO is clear that medicine alone is not the answer. Health education and better sanitation are what stop children being reinfected between treatments.

What is deworming and who needs it?

In places where worm infection is common, WHO recommends periodic deworming, also called preventive chemotherapy, given to whole at-risk groups without testing each child first. The aim is to keep the worm burden low enough that children grow and learn normally. In 2021 more than 500 million children were treated this way, which was about 62% of the children who needed it.

Deworming tablets should come from a health worker, a clinic, or an official school or community campaign, which is where the correct dose for a child's age is decided. Do not buy and give worm medicine on your own guess. A doctor can also confirm an infection by examining a stool sample under a microscope if your child has symptoms.

When to see a doctor

See a doctor rather than waiting for the next deworming round if your child has:

• Blood in the stool, or black stools
• Stomach pain that keeps coming back, or ongoing diarrhoea
• Looking pale, unusually tired, breathless or dizzy, which can be signs of anaemia
• Poor appetite, weight loss, or not growing as expected
• Worms visible in the stool or vomit

Take a child to hospital straight away if they have severe stomach pain with a swollen abdomen and repeated vomiting, or become very weak, drowsy or hard to wake. In an emergency, call Rescue 1122 where available, or go to the nearest hospital emergency department.