Strongyloidiasis

Key Facts

Terminology

Synonyms
- Cochin China diarrhea, thread worm infection
Definition
- Parasitic infection caused by nematode

Clinical Issues

Epidemiology
- Worldwide distribution
- More common in tropical countries
- High in conditions that promote fecal contamination
Symptoms
- Urticaria
- Cough
- Dyspnea
- Hemoptysis
- Bronchopneumonia
- Intermittent diarrhea
Laboratory tests
- Eosinophilia
- Leukocytosis
- Feces study is important in diagnosis
- Enzyme-linked immunosorbent assays (ELISA) for IgG antibodies to antigens of larvae of Strongyloides

Microscopic Pathology

Inflammatory reaction with prominent eosinophils
Suppurative exudate
Presence of larvae
Presence of adult worm

Low-power view of a pulmonary airway shows respiratory epithelium with inflammatory changes and focal necrosis. Even at this power, it is possible to identify some filariform larvae

High-power view shows rhabditiform larvae of Strongyloides

admixed with necrosis. The rhabditiform larva is most commonly encountered on histological examinations.

TERMINOLOGY

Synonyms

Cochin China diarrhea, thread worm infection

Definitions

Parasitic infection caused by a nematode

ETIOLOGY/PATHOGENESIS

Infectious Agents

Strongyloides stercoralis

3 Cycles of Infection

Direct
- Filariform larvae penetrate the skin
  - Cutaneous phase may last a few days
Indirect
- Rhabditiform larvae mature into free-living males and females in the soil
Autoinfection
- Rhabditiform larvae become infective filariform larvae in intestine or skin of the host

CLINICAL ISSUES

Epidemiology

Incidence
- Worldwide distribution
- More common in tropical countries
- High in conditions that promote fecal contamination
Age
- Affects any age group
Gender
- Infection may be more common in males
Ethnicity
- No ethnic predisposition

Presentation

Skin itching
Skin edema
Urticaria
Low-grade fever
Cough
Dyspnea
Hemoptysis
Bronchopneumonia
Intermittent diarrhea
Cramping
Constipation
Anemia
Asymptomatic

Laboratory Tests

Eosinophilia
Leukocytosis
Feces study is important in diagnosis
Enzyme-linked immunosorbent assays (ELISA) for IgG antibodies to antigens of larvae of Strongyloides

Treatment