Strongyloides infection should be considered in all migrants or residents from endemic areas regardless of time since immigration.
Clinical clues include wheezing, abdominal distress, and eosinophilia.
Stool ova and parasite tests are relatively insensitive for detection of strongyloides larvae but are currently the tests of choice.
Treatment with ivermectin is recommended, regardless of resource setting.
Rapid spread of infection can lead to hyperinfection syndrome and disseminated disease, both of which are associated with a high mortality rate in immunosuppressed patients.
Empirical treatment should be considered when initiating corticosteroids in any high-risk patient due to risk of life-threatening hyperinfection.
Strongyloidiasis is an infection caused by the intestinal nematode Strongyloides stercoralis. Transmission occurs widely in tropical and subtropical areas, but also in countries with temperate climates. The primary mode of infection is through larvae penetrating the skin. Strongyloides larvae migrate from subcutaneous tissues into the venous circulation, then to the lungs. Larvae migrate up the airways, are swallowed, and establish chronic infection in the intestinal tract as adults. New larvae continue this cycle within the human host creating indefinite auto-infection; meaning that, without treatment, infection is lifelong.
History and exam
Key diagnostic factors
- presence of risk factors
- infection with other parasites
Other diagnostic factors
- abdominal pain
- altered bowel habit
- weight loss
- fever (hyperinfection)
- signs of sepsis (hyperinfection)
- chronic cough
- pruritus or dermatitis
- larva currens
- cutaneous larva migrans
- apparent drug reaction rash (hyperinfection)
- other skin complaints
- symptoms and signs of inflammatory bowel disease
- soil exposure in or migrants from an endemic area of the world
- international travellers
- corticosteroids (risk of hyperinfection)
- human T-cell lymphotropic virus type-1 (HTLV-1) infection (risk of hyperinfection)
- impaired immunity
- solid-organ transplant recipient
1st investigations to order
- stool ova and parasites (O&P) examination
- FBC with differential
- therapeutic trial with ivermectin (in specific situations)
Investigations to consider
- sputum O&P examination
- clinical sample (non-stool or sputum) O&P examination
- strongyloides IgG serology
- tissue biopsy
- polymerase chain reaction (PCR)
immigrant from endemic area
able to tolerate oral therapy: not critically ill (nonpregnant)
unable to tolerate oral therapy or critically ill (nonpregnant)
poor clinical response or initial treatment not completed
David R. Boulware, MD, MPH, CTropMed
Professor of Medicine
Department of Medicine
University of Minnesota
DRB is an author of a number of references cited in this topic.
Elizabeth Barnett, MD
Department of Pediatrics
Boston Medical Center
EB declares that she is on a speaker's bureau for Merck. She is an author of a reference cited in this topic.
Linda Nield, MD, FAAP
Professor of Pediatrics
West Virginia University School of Medicine
LN is an author of a reference cited in this topic.
Geoff Gill, MA, MSc, MD, FRCP, DTMH
Professor of International Medicine and Honorary Consultant Physician
Liverpool School of Tropical Medicine
GG declares that he has no competing interests.
- CDC health information for international travel (the Yellow Book). Chapter 4: travel-related infectious diseases (strongyloidiasis)
- CDC parasites - strongyloides: resources for health professionals
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