Intestinal worms: causes, symptoms and treatment

What are intestinal worms?

These worm-like intestinal parasites live inside the digestive system and feed off nutrients from their host, causing the infected person to become malnourished and susceptible to disease and chronic illness.

Intestinal worms are one of the most common infections in humans worldwide.

What causes intestinal worms?

Adult worms live in an infected person’s intestine, where they produce thousands of eggs each day. The parasitic infection is spread when these eggs are passed in human faeces and contaminate the soil.

In low-income communities with poor access to clean water and sanitation, the eggs can be ingested through contaminated soil on unwashed vegetables and hands, and contaminated water sources.

What are the symptoms of intestinal worms?

At first, the signs and symptoms of intestinal worms may be mild or non-existent, but symptoms can include:

• Diarrhoea and abdominal pain
• Weakness
• Malnutrition, which can lead to anaemia
• Inflammation in the large intestine
• Intestinal obstruction (blockage in the bowel)

The disease can impair cognitive and physical development, and in severe cases can be life threatening. It can also decrease people’s quality of life in the long term, affecting their employment, fertility and happiness. Children with the infection may be forced to miss school, damaging their education and progression.

How we’re tackling intestinal worms

Our aim is to control the disease in the countries where we run deworming programmes, including in Cameroon, Democratic Republic of Congo, Nigeria and Guinea.

Through our community and school programmes, we educate local communities about the importance of good hygiene to stop the spread of intestinal worms.

Our School Health Integrated Programming project aims to reduce school absences and boost children’s educational prospects. Since 2016, the project has worked alongside governments in Africa and Asia to improve students’ health and provide deworming treatments. The disease is often treated at the same time as schistosomiasis.

In 2023, we treated more than five million people for intestinal worms, and trained more than 100,000 local volunteers to distribute medication for a range of neglected tropical diseases such as trachoma. With your support, we can reach even more people and protect them from intestinal worms, so they can earn, learn and thrive.

Page last reviewed: January 2025
Next review due: January 2028
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