Mode of transmission: percutaneous penetration of larvae (primarily via the feet)
Life cycle
The Strongyloides eggs hatch in the human intestine and release larvae→ larvae are excreted in feces and contaminate the soil→ larvae penetrate the intact skin of the definitive host upon contact with contaminated soil → larvae migrate to the lungs via the bloodstream → larvae migrate to the pharynx via the alveoli and bronchial system → larvae are swallowed, causing autoinfection → larvae mature into adult, egg-producing worms in the intestine → eggs develop into infectious larvae and are excreted in feces
Hyperinfection: Some larvae may penetrate the intestinal wall and enter the bloodstream (rare).
Pathophysiology
Clinical features
Cutaneous phase
Swelling, erythema, maculopapular rash at the site of larval penetration
Larva currens: raised serpiginous lesions or urticarial tracts due to migration of larvae under the skin in autoinfection; pathognomonic of S. stercoralis infection
