What is strongyloidiasis?

Updated: Jun 20, 2019
  • Author: Pranatharthi Haran Chandrasekar, MBBS, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Strongyloidiasis is an intestinal infection caused by 2 species of the parasitic nematode Strongyloides. The most common and clinically important pathogenic species in humans is S stercoralis (see the following image). S fuelleborni is found sporadically in Africa and Papua New Guinea. Distinctive characteristics of this parasite are its ability to persist and replicate within a host for decades while producing minimal or no symptoms (individuals with an intact immune system) and its potential to cause life-threatening infection (hyperinfection syndrome, disseminated strongyloidiasis) in an immunocompromised host (60-85% mortality rate). [1, 2, 3]

Rhabditiform larva of Strongyloides stercoralis in Rhabditiform larva of Strongyloides stercoralis in stool specimen (wet mount stained with iodine).

The symptoms related to strongyloidiasis may reflect the nematode's systemic passage, its local cutaneous involvement, or both. During chronic uncomplicated infections, the larvae may migrate to the skin, where they can cause cutaneous strongyloidiasis, known as larva currens because of the quick migratory rate of the larva. Infection is clinically characterized by watery diarrhea, abdominal cramping, and urticarial rash. In malnourished children, strongyloidiasis remains an important cause of chronic diarrhea, cachexia, and failure to thrive.

This condition can also be a health consequence of captivity. During the World War II, allied military personnel held by the Japanese experienced deprivation, malnutrition, and exposure to tropical diseases. [4] Certain tropical diseases have persisted in these survivors, notably infections with S stercoralis, with studies 30 years or more after release documenting overall infection rates of 15%. Chronic strongyloidiasis may produce a linear urticarial larva currens rash, with such individuals at risk of fatal hyperinfection if immunity is suppressed.

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