Strongyloidiasis is a human parasitic disease caused by the nematode called Strongyloides stercoralis, or sometimes the closely related S. fülleborni. These helminths belong to a group of nematodes called roundworms. These intestinal worms can cause a number of symptoms in people, principally skin symptoms, abdominal pain, diarrhea and weight loss, but also many other specific and vague symptoms in disseminated disease, and severe life-threatening conditions through hyperinfection. In some people, particularly those who require corticosteroids or other immunosuppressive medication, Strongyloides can cause a hyperinfection syndrome that can lead to death if untreated. The diagnosis is made by blood and stool tests. The medication ivermectin is widely used to treat strongyloidiasis. Strongyloidiasis is a type of soil-transmitted helminthiasis. Low estimates postulate it to affect 30–100 million people worldwide, mainly in tropical and subtropical countries, while higher estimates conservatively extrapolate that infection is upwards to or above 370 million people. It belongs to the group of neglected tropical diseases, and worldwide efforts are aimed at eradicating the infection. Signs and symptoms Strongyloides infection occurs in five forms. As the infection continues and the larvae matures, there may be respiratory symptoms (Löffler's syndrome). The infection may then become chronic with mainly digestive symptoms. On reinfection (when larvae migrate through the body) from the skin to the lungs and finally to the small intestine, there may be respiratory, skin and digestive symptoms. Finally, the hyperinfection syndrome causes symptoms in many organ systems, including the central nervous system. Uncomplicated disease Frequently asymptomatic. Gastrointestinal system symptoms include abdominal pain and diarrhea and/or conversely constipation. Pulmonary symptoms (including Löffler's syndrome) can occur during pulmonary migration of the filariform larvae. Pulmonary infiltrate may be present through radiological investigation. Dermatologic manifestations include urticarial rashes in the buttocks and waist areas as well as larva currens. Eosinophilia is generally present. Strongyloidiasis can become chronic and then become completely asymptomatic. Disseminated disease Disseminated strongyloidiasis occurs when patients with chronic strongyloidiasis become immunosuppressed. There is a distinction to be made between dissemination and hyperinfection. It is mainly a semantic distinction. There can be mild dissemination where the worm burden is relatively lower yet causes insidious symptoms, or extreme dissemination that the term hyperinfection is used to describe. Thus hyperinfection of varying levels of severe dissemination may present with abdominal pain, distension, shock, pulmonary and neurologic complications, sepsis, haemorrhage, malabsorption, and depending on the combination, degree, number, and severity of symptoms, is potentially