Strongyloidiasis

Question 1

Strongyloidiasis - parasite

Answer 1

Strongyloides stercoralis
rhabditid nematode [roundworm]

Question 2

Strongyloides - adult size

Answer 2

0.1cm

Question 3

Strongyloides - free-living life cycle

Answer 3

Rhabditiform larvae passed in stool and develop into either: infective filariform larvae [direct development] or into freeliving adult males and females that mate and produce eggs
Eggs eventually develop into infective filariform larvae

Question 4

Strongyloides - parasitic lifecycle

Answer 4

Filariform larvae in contaminated soil penetrate human skin
Migrate to the small intestine via multiple routes:
-Blood and lymphatics to lungs - pharynx -GI
-Through abdominal viscera and connective tissue
In the small intestine - larvae molt twice and become adult female worms
Females live embedded in submucosa of small intestine and asexually reproduce eggs via parthenogenesis
Rhabditiform larvae can either be passed into stool or cause autoinfection

Question 5

Strongyloides - clinical presentation

Answer 5

Usually asymptomatic
Cutaenous larve currens - pruritic, moves linearly. Faster moving and shorter duration than hookworm [larva migrans]
Larval migration in lungs - cough, wheeze, Loeffler’s
GI - abdominal pain, intermittent diarrhoea

Question 6

Strongyloides - hyperinfection

Answer 6

Can occur in immunosuppressed individuals with T lymphocyte depletion - leads to faster reporduction cycle and mgiration to ectopic sites
Spread of bacteria from faeces to normally sterile sites can lead to recurrent gram negative bacteraemia, CNS involvement
-Eosinophilia rare [compared to increased in normal strongyloides]
-Gram negative rod sepsis

Question 7

Strongyloides - diagnosis

Answer 7

Eosinophilia - up to 80%
Faecal OCP
Serology - ELISA IgG
14 day charcoal culture

Question 8

Strongyloides - management

Answer 8

Ivermectin - preferred over albendazole