Mi - Worms Flashcards
what is the medical word for worms
helminths
how do worms cause rapid vs slow damage
rapid = humans aren’t their natural host
slow = worms / eggs try to escape
3 types of worms
cestodes
trematodes
nematodes
what are cestodes aka
tape worms
2 types of cestodes
pork / beef / fish
hydatid
what do cestodes look like
flat, segmented (oldest at the end)
what are trematodes aka
flukes
4 places trematodes can invade
lung / liver / intestinal / blood
what is the trematode that infects blood called
schistosomiasis
what are nematodes aka
roundworms
3 types of nematodes
hookworms
ascaris
tichuris enchuria
what do nematodes look like
round with body cavity
what is the definitive and intermediate host in the pork / beef tapeworm
human is definitive host
cow / pig is intermediate host
what is pork / beef tapeworm called
taenia
what is the taenia disease called
cystercicosis
what happens inside the human when it gets cystercicosis from taenia
taenia keeps growing as the human is effectively acting like the pig (intermediate host)
what is the definitive / intermediate / accidental host in hydatid disease
intermediate = sheep / goats
definitive = foxes / dogs
accidental = humans
what disease does hydatid look like
cystercicosis
how is hydatid disease passed
via dog poo
tx of hydatid disease worms
praziquantel
tx of hydatid disease cysts
PAIR surgery - suck out contents
albendazole long term
tx of cystersicosis (3)
albendazole
prazinquantel
steroids
worms only cause issues for humans when they are the ____ host not the ____ host
issues = accidental intermediate host
no issues = definitive host
how are cysts in cystercisosis / hydatid diagnosed
imaging and serology
how many species of schistosomiasis are there
4
where is schistosomiasis mainly found
africa !!!! no1
SE asia
south /cent america
3 organs that schistosomiasis damages
bladder / bowel
liver
how does schistosomiasis damage the bladder / bowel
migration of eggs through bladder / bowel –> can get TCC of bladder
how does schistosomiasis damage the liver
retrograde passage of eggs through liver –> cirrhosis
schistosomiasis is the only fluke that has both ____ ?
sexes (ie there are males and females)
lifecycle of schistosomiasis
pair up M&F –> eggs –> migrate through bladder –> pass into water –> hatch into snails –> burrow into human foot –> find venous plexus –> find mate –> eggs
how is schistosomiasis diagnosed
microscopy of terminal urine
stool culture
serology (ABs)
biopsy
what species is isolated from urine microscopy in schistosomiasis
s. haematomiab
what species is isolated from stool in schistosomiasis
s.triansoni
sx of schistosomiasis
haematuria
tx of schistosomiasis
prazinquantel
how is schistosomiasis prevented
hard
- kill snails
- mass tx with prazinquantel
- avoid snails / fresh water
what causes damage in schistosomiasis
egg deposition
how are nematodes transmitted
soil –> food / transdermal
general prognosis for nematodes
not really, don’t cause too much trouble
how do nematodes cause disease (4)
migration
worm burden
malabsorption and blood loss
psychological distress
lifecycle of ascaris
eggs swallowed in food –> hatch in stomach –> travel to gut –> eggs
name another nematode
strongyloides
what special skill does strongyloides have that no other helminth does
autoinfection (all cell cycle is in humans)
how does strongyloides autoinfect humans
eggs hatch in stool to form larvae –> if stool is still in rectum, then they can reinfect the same human if worm is mature enough
sx of soil transmitted helminths
usually none - most people will never know they have them
what carries filiariasis
blackflies / mosquitos
types of filiariasis (3)
lymphatic
subcut
seroud cavity
what is included in a parasite screen (including 3 bugs to look for)
serology - stronglyoides / schistosomiasis / filaria
stool micro
filaria lifecycle
adult worms pass eggs –> sucked up by vector –> injected into next host
2 complications of filariasis
elephantitis
river blindness
dx of filariasis
find them in blood / skin
ABs via ELISA
USS - see adult worms
what is the name of the sign on USS of adult filaria worms moving
dance sign
what is myiasis
parasitisation of human flesh by fly larvae
what 2 flies cause myiasis and where is each endemic to
bot fly - south america
tumbu fly - africa
why does myiasis cause local damage
maggots burrow into flesh
who in UK gets myiasis and why
homeless people - they are opportunistic here so only invade ulcers not cared for etc
other than parasites, what can cause a raised eosinophils
atopy
allergy
HL / NHL
SLE
what type of helminth comes out of the leg
guinea worm
which helminth lives in the bowel and is passed from food
ascaris
febrile child with worms coming out of nose / mouth / bum / every oriffice. what is the helminth and why is it doing that?
ascaris
- doesn’t like heat
what % of hydatid serology is negative in infected people
25%
what bug causes subcutaneous swelling as they spread
Loa Loa
