14.2 - strongyloides and hookworm Flashcards
roundworms found in
impoverished areas with faecal contamination eg. indigienous communities in central and northern australia
strongyloides stercoralis
filariform larvae in soil penetrate the skin
larvae pass to lungs in circulation
migrate to trachea and larynx and are swallowed
develop into adults and produce ova in the intestine
strongyloides stercoralis ova
hatch to release rhabditiform larvae
rhabditiform larvae excreted in stools
development to filarifirm larvae occurs in soil
stronglyloides stercoralis auto infection
rhabditiform larvae can develop into filariform larvae, penetrate mucosa or perianal skin to continue cycle of infection
often asymptomatic
symptoms of strongyloides stercoralis auto infection
diarrhoea and abdominal pain
pulmonary symptoms can occur with lung migration
strongyloides hyper infection
particularly immunocompromised patients/steroid therapy
disseminated disease can occur which may be fatal
strongyloides stercoralis chronic infection
may persist for many years
strongyloides stercoralis diagnosis
light microscopy is the main method
visualisation of rhabditiform larvae in concentrated stools
culture for larvae can be performed
serology also available
hookworm 2 species
nectar americanus
ancylostoma duodenale
main species of hookworm found in australia
ancylostoma duodenale
hookworm infective larvae found in
contaminated soil
larvae penetrate skin and carried in blood to heart and then lungs
hookworm larvae attach to
small intestine, where they mature to adults
hookworm adults
shed ova into lumen
ova passed in faeces
major signs of hookworm infection
iron deficiency anaemia due to GI blood loss
symptoms of hookworm infection
may impair growth and mental development in children
most infections are asymptomatic
pruritis and rash may occur at site of larval penetration
abdominal pain, weight loss , diarrhoea
cough and wheeze may occur during larval migration through the lungs
