a human parasitic disease caused by the nematode (roundworm) Strongyloides stercoralis, or sometimes S. fülleborni.
thought to affect 30–100 million people worldwide, mainly in tropical and subtropical countries.
it is a helminth that is endemic to tropical and subtropical regions of the world, across Central and South America, sub-Saharan Africa, northern Australia and Asia
does not require an intermediate host but does require maturation in soil
infection is via either:
filariform larva from soil penetrating intact skin, or,
auto-infection by rhabditiform larvae in the colon penetrating bowel wall or peri-anal skin
risk for infection is particularly in those who walk barefoot in endemic faecally contaminated soil such as rural areas with poor sanitation
systemic corticosteroids have precipitated death in more than 60% of disseminated strongyloidiasis cases
Aboriginal and Torres Strait Islander patients from rural and remote areas in Australia should not be given immunosuppressive treatment without being tested or treated prophylactically for strongyloidiasis 1)
Loffler's syndrome (acute onset eosinophilic pneumonitis) can also be caused by Ascaris lumbricoides, and the hookworms Ancylostoma duodenale and Necator americanus.
chronic with mainly digestive symptoms
may become asymptomatic
abdominal pain, diarrhoea, eosinophilia, urticarial rashes (esp. waist and buttocks)
reinfection with larva migration
there may be respiratory, skin and digestive symptoms
hyperinfection in the immunocompromised
may involve many organ systems including CNS
may occur many decades after initial infection and develops when immunity falls eg. high dose corticosteroids, organ transplant drugs, malnutrition, advanced tuberculosis (TB), etc.
high mortality rate and may lead to disseminated infection
Rx
uncomplicated disease
The drug of choice for the treatment of uncomplicated strongyloidiasis is ivermectin.
ivermectin does not kill the strongyloides larvae only the adult worms therefore repeat dosaging may be necessary to properly eradicate the infection.
There is an auto-infective cycle of roughly two weeks in which ivermectin should be re-administered however additional dosaging may still be necessary as it will not kill strongyloides in the blood or larvae deep within the bowels or diverticuli.