Strongyloides stercoralis (PCR)

Stool

Strongyloides stercoralis is a nematode that can live freely in the soil as well as a parasite in humans where it causes the disease strongyloidasis.

The tiny larvae can penetrate the skin of humans, enter the bloodstream and reach the alveoli through the lung capillaries. They get then coughed up or migrate on their own towards the throat, get swallowed and reach the small intestines where they lay eggs, which in turn give rise to larvae. These are either excreted in the faeces or enter the bloodstream via the wall of the small intestine. This results in a self-infection or auto-infection.

Due to the parasites' journey through multiple organ systems, multiple symptoms occur.
Infestation of the skin leads to larva migrans cutanea syndrome (also called larva currens syndrome).
In the lungs, the infestation is characterised by chronic bronchitis, pneumonia or dyspnoea. Symptoms of the intestinal area are mainly nausea, bloating, bloody diarrhoea and vomiting, but the extent of infection in the intestines depends on the strength of the immune system. In immunocompromised patients numerous larvae can be found in the mesenteric vessels, the intestinal wall and the bile ducts, but also in unexpected places such as the lymph nodes or even in the spinal fluid and urine, causing further symptoms.

Finding Strongyloides in stool can be a tedious matter as even in infected patients up to 70% of stool samples can be negative. So it is important to do frequent stool sampling and analysis if an infection with Strongyloides is suspected.