Strongyloidiasis

Strongyloides stercoralis is a human parasitic nematode worm. The filariform (infectious) larvae are present in soil and gain access to the body by penetrating the skin. Infection with Strongyloides stercoralis causes strongyloidiasis.

On contact, the larvae penetrate the skin and migrate hematogenously to the lungs --> enter the alveoli --> bronchial tree --> pharynx --> swallow back

When the larvae reach the intestine, they develop into adults that lay eggs within the intestinal mucosa --> hatch into rhabditiform (noninfectious) larvae --> migrate into the intestinal lumen --> excreted in the stool

Features

• diarrhoea
• abdominal pain/bloating
• papulovesicular lesions where the skin has been penetrated by infective larvae e.g. soles of feet and buttocks
• larva currens: pruritic, linear, urticarial rash
• if the larvae migrate to the lungs a pneumonitis similar to Loeffler's syndrome may be triggered

Investigation

• eosinophilia (may be absent in hyperinfection)
• stool microscopy: rhabditiform larvae (eggs are not seen in stool)
• serology (ELISA for Strongyloides IgG) is sensitive for diagnosis

Treatment

• ivermectin and albendazole are used

Although albendazole can be used as an alternative to ivermectin in the treatment of Strongyloides stercoralis, head-to-head trials have shown ivermectin to be more effective in curing people of the condition with a comparable side effect profile. As such ivermectin is the suggested first-line treatment