Strongyloidiasis

Key facts

• Strongyloidiasis is an intestinal infection caused by the roundworm Strongyloides stercoralis, which can reproduce inside the human body, so an untreated infection can persist for decades.
• The worm lives in warm, moist soil and enters through bare skin, most often the feet; it is common across tropical and subtropical regions.
• Many infections cause no symptoms for years; when they appear, expect an itchy, migrating rash at the entry site, abdominal discomfort, bloating, and intermittent diarrhoea.
• Treatment is a short course of ivermectin; people with weakened immunity should seek prompt care if respiratory symptoms appear alongside gut symptoms.

Who is at risk and how it spreads

The worm lives in warm, moist soil and enters the body through bare skin, usually the feet. Rural communities, agricultural workers, and anyone walking barefoot on contaminated soil in warm climates face heightened exposure. People with weakened immune systems, including those on long-term corticosteroids, are at risk of hyperinfection, a severe form where larvae spread beyond the gut and can affect other organs.

Recognising the symptoms

Many infections cause no obvious symptoms for years, which is part of what makes this parasite unusual: it can keep reproducing inside the body indefinitely without treatment. When symptoms do appear, they typically include a moving, itchy rash at the entry site, abdominal discomfort, bloating, and intermittent diarrhoea. Hyperinfection can produce fever, cough, and severe gastrointestinal distress, and needs urgent medical attention.

How strongyloidiasis is treated

Treatment relies on ivermectin, which clears the infection effectively in a short course. It belongs to the antiparasitic medicines used against worm and parasite infections generally. Because the worm can persist silently, anyone with a history of exposure to contaminated soil, even years earlier, should mention it to a doctor before starting long-term steroids or other immune-suppressing treatment.

When to see a doctor

Anyone who suspects hyperinfection, or who develops respiratory symptoms alongside gut symptoms, should seek medical attention promptly, as this form can become life-threatening without treatment.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.