What is Strongyloides?
Strongyloides is a parasitic roundworm that can infect humans and live in the small intestine. It is unusual compared with many other parasitic infections because it can continue to reproduce inside the body after the initial infection. This means a person can remain infected for many years, sometimes without realising it, unless it is diagnosed and treated.
Infection usually happens when tiny larvae in contaminated soil come into contact with the skin and penetrate it. This most often occurs through bare feet or direct skin exposure to soil or ground that has been contaminated with human waste. After entering the body, the parasite travels through the bloodstream and lungs before settling in the intestine, where it continues its lifecycle.
The World Health Organization (WHO) estimates that strongyloidiasis affects approximately 30–100 million people globally, mainly in tropical and subtropical regions where warm climates and limited sanitation increase the chance of soil contamination.
FAQs
Where am I most likely to be exposed while travelling?
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Exposure is most commonly linked to walking barefoot or having direct skin contact with soil that contains infectious larvae. This can occur in tropical and subtropical regions, particularly in parts of Southeast Asia, the Pacific, Africa, and Central and South America. Risk settings include rural villages, agricultural areas, walking barefoot on beaches or unsealed ground, and environments where sanitation infrastructure is limited. Even brief soil contact can be enough for infection to occur if larvae are present.
Can strongyloides infection stay in the body for a long time?
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Yes. One of the unique features of strongyloides is its ability to maintain a cycle of self-infection inside the human body. This means the parasite can persist for decades without obvious symptoms. In some cases, people may only become aware of infection many years later, sometimes when their immune system becomes weakened due to illness or medication.
What should I do if I think I’ve been exposed to strongyloides?
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There is usually no immediate symptom at the time of exposure, so infection can be difficult to recognise early. If you have travelled to a higher-risk region and had barefoot soil contact or possible exposure, it is reasonable to discuss this with a GP or travel health clinic. They may recommend stool testing or preventive treatment depending on your risk history, even if you feel completely well.
Is strongyloides dangerous?
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Most people with chronic infection may have mild or no symptoms for years. However, in certain situations, particularly if the immune system becomes suppressed through factors such as steroid medication or serious illness, the infection can become severe and spread beyond the gut to the bloodstream and other organs. This is why identifying and treating infection early is important, even when symptoms are minimal or absent.
Can I catch strongyloides from another person?
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Direct person-to-person spread is uncommon. Infection usually comes from contact with contaminated soil rather than human contact.
What to Know
Strongyloidiasis symptoms
Many infections are subtle and may go unnoticed for long periods. When symptoms do occur, they can vary depending on how long the infection has been present and the individual’s immune response. Some people experience intermittent abdominal discomfort, bloating, nausea, or changes in bowel habits. Others may develop skin-related symptoms such as itchy, raised, or moving rashes, often described as a “creeping” sensation under the skin, particularly around the feet, buttocks, or abdomen.
Respiratory symptoms can also occur, including coughing, wheezing, or shortness of breath, especially during early stages when larvae migrate through the lungs. In long-standing infection, symptoms may be vague and non-specific, such as fatigue or generalised gastrointestinal discomfort. In severe cases, particularly in immunocompromised individuals, the infection can spread throughout the body and affect multiple organ systems, leading to serious systemic illness.
Strongyloidiasis diagnosis and treatment
Diagnosis can be challenging because infection may not always be detected on standard stool testing alone. Blood tests looking for specific antibodies can be used in travel and screening contexts, particularly for people who have lived in or travelled to higher-risk regions.
Treatment initiated by a doctor is generally straightforward once infection is identified. The most commonly used medication is ivermectin, which is highly effective in clearing the parasite in most cases. Treatment is often given as a short course, and in some situations further medication or follow-up testing may be recommended to confirm clearance. Early treatment is particularly important because it significantly reduces the risk of long-term complications.
Strongyloidiasis prevention
Prevention focuses on avoiding skin contact with contaminated soil. The most effective protective measure is wearing footwear outdoors, particularly in rural or tropical environments where sanitation infrastructure may be limited. Avoiding walking barefoot on soil, sand, or wet ground in high-risk areas significantly reduces the chance of infection.
Additional protective behaviours include using barriers such as sandals or shoes in beach and rural settings, avoiding sitting directly on bare soil, and maintaining good personal hygiene when returning from outdoor environments. For individuals who have lived in or had prolonged exposure in endemic regions, discussing screening with a healthcare provider can be appropriate, even if no symptoms are present.