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Strongyloidiasis

Chronic intestinal nematode infection with risk of life-threatening hyperinfection

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Internal Medicine department. Book Appointment →

What is Strongyloidiasis?

Strongyloides stercoralis is a soil-transmitted nematode endemic in tropical, subtropical, and temperate regions including Southeast Asia, sub-Saharan Africa, Latin America, parts of southern Europe (former Mediterranean basin), and southeastern United States. Filariform larvae penetrate intact skin (typically barefoot exposure to contaminated soil), migrate via lymphatics to lungs, ascend the trachea, are swallowed, and mature in the small intestine.

Unique among soil-transmitted helminths, Strongyloides exhibits autoinfection: rhabditiform larvae transform into infectious filariform larvae within the host, penetrating intestinal mucosa or perianal skin to perpetuate infection lifelong. Most chronic infections are asymptomatic or mildly symptomatic with intermittent gastrointestinal, dermatologic (larva currens), and pulmonary symptoms.

Hyperinfection syndrome and disseminated strongyloidiasis occur when host immunity is compromised, especially with corticosteroid therapy (the most important risk factor), HTLV-1 coinfection, transplantation, hematologic malignancy, or HIV. These severe forms feature massive larval proliferation with gastrointestinal hemorrhage, polymicrobial bacteremia/meningitis from gut flora translocation, pulmonary hemorrhage, and high mortality (50-85%). Universal screening before immunosuppression in at-risk populations is essential.

Symptoms

Often asymptomatic in chronic infection
Intermittent abdominal pain, nausea, diarrhea
Larva currens (rapidly migrating serpiginous urticaria, perianal/buttock distribution)
Pruritic urticarial rash
Cough, wheezing (Loeffler-like pulmonary syndrome)
Dyspnea
Eosinophilia (often mild but persistent)
Weight loss, malabsorption (chronic heavy infection)
Recurrent gram-negative bacteremia (hyperinfection)
Sepsis, polymicrobial bacteremia
Meningitis (gut flora)
Pulmonary hemorrhage, ARDS-like presentation
Gastrointestinal hemorrhage
Paralytic ileus
Nausea, vomiting, severe abdominal pain (hyperinfection)
Hyperinfection symptoms after corticosteroid initiation
Diarrhea with blood
Petechial purpuric rash (disseminated disease)
Confusion, altered mental status (CNS dissemination)

Risk Factors

Travel or residence in endemic regions
Barefoot exposure to contaminated soil
Agricultural occupation
Migration from endemic countries
HTLV-1 coinfection (most important hyperinfection risk after corticosteroids)
Corticosteroid therapy (any dose, any duration)
Solid organ or hematopoietic stem cell transplantation
Hematologic malignancy (especially with chemotherapy)
HIV (less risk than expected)
Hypogammaglobulinemia
Diabetes mellitus
Alcoholism, chronic liver disease
Malnutrition
Veterans (especially Vietnam-era)
Refugees, immigrants from endemic areas
Immunosuppressive medications (calcineurin inhibitors, biologics)
Anti-TNF therapy
Asplenia
Older age

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Persistent unexplained gastrointestinal symptoms in patient with travel/residence in endemic area
  • Eosinophilia (any value above normal)
  • Larva currens skin rash
  • Recurrent gram-negative or polymicrobial bacteremia
  • Sepsis of unclear source in immunosuppressed patient
  • Pulmonary symptoms with eosinophilia in returning traveler
  • Before initiating corticosteroids in patient from endemic area
  • Before solid organ or stem cell transplantation in at-risk recipient
  • Before chemotherapy or immunosuppression in at-risk patient
  • HTLV-1 positive patient
  • Refugees and immigrants from endemic areas (universal screening)
  • Veterans with possible exposure history

Treatment Methods

01
Universal screening of at-risk populations before immunosuppression with serology (ELISA or immunoblot, sensitivity 80-90%)
02
Stool ova and parasite examination (low sensitivity, requires multiple specimens, agar plate culture more sensitive)
03
Stool PCR (where available)
04
Duodenal aspirate or biopsy for larvae in select cases
05
Sputum or BAL examination for larvae in pulmonary disease
06
Eosinophil count (often elevated in chronic infection but may be absent in hyperinfection)
07
HTLV-1 testing in seropositive or epidemiologically at-risk patients
08
First-line therapy: ivermectin 200 mcg/kg orally once daily for 1-2 days for chronic uncomplicated infection
09
Hyperinfection or disseminated disease: ivermectin 200 mcg/kg daily until symptom resolution and 2 weeks of negative stool/sputum, often combined with subcutaneous or rectal ivermectin (compassionate use)
10
Albendazole 400 mg twice daily for 7 days as alternative or combination
11
Test of cure: stool ova and parasite at 2 and 6 weeks, and serology decline (slow, may take 6-12 months)
12
Empiric therapy before corticosteroids in at-risk patient if testing not available
13
Strict barrier precautions for hyperinfection cases
14
Treat HTLV-1 with antiviral therapy when indicated
15
Manage bacterial superinfections with broad-spectrum antibiotics
16
Supportive care including ICU management for severe disease
17
Ivermectin treatment of household members and close contacts in symptomatic cases
18
Public health measures including sanitation, footwear, hygiene education in endemic areas
19
Annual or biannual screening in HTLV-1 positive or chronically immunosuppressed patients
20
Avoid corticosteroids if possible in untreated patient

Which Department to Visit?

You can visit our Enfeksiyon Hastalıkları department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

Learn About Enfeksiyon Hastalıkları Department

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.