Helminths - Trematodes and Cestodes Flashcards Preview

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Flashcards in Helminths - Trematodes and Cestodes Deck (15)
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1
Q

differentiate trematodes and cestodes

A

flatworms

  • trematodes are non-segmented flatworms/flukes; have 2 sexes
  • cestodes are flatworms w/segments; each individual section has both sexual organs; hermaphrodites
2
Q

life cycle of schistosomes

A

cercariae are found in water humans swim in

penetrate skin, lose tail, migrate to portal circulation

adults form in liver, then move to either intestinal, GU veins to lay eggs

eggs leave in feces or urine and hatch inf reshwater as miracidia

miracidia infect snails where they develop back into cercariae

3
Q

where do schistosome infections occur?

A

contaminated fresh water; eggs released into fresh water will hatch into the infectious cercariae

4
Q

where do schistosoma mansoni, japonicum, haematobium migrate to lay eggs respectively?

A

s. mansoni and s. japonicum migrate to mesenteric venules

s. haematobium go to bladder veins

5
Q

desribe the shape of eggs from the schistosoma spp.

s. mansoni

s. haematobium

s. japonicum

A
6
Q

what actually casues the damage in schistosomiasis?

what are the clinical manifestations of each spp.?

A

eggs are what cause the immune response/damage

acute: fever, HA, coug, ab pain, eosinophilia, prostration

chronic: eggs trapped in tissue; eosinophilic reaction; granulomas develop; fibrosis

  • s. mansoni, japonicum: bloody diarrhea, intestinal polyps, anemia
    • physical/mental growth retardation in childhood
  • s. haematobium: hematuria, bladder calcifications
  • neural schistosomiasis: abberent eggs can go to brain and cause inflammation
7
Q

treatment of schistosomiasis

A

praziquantel

freezes worms exposing antigens; increases Ca2+ permeability across worm

8
Q

how do liver flukes cause disease?

where are infections acquired?

A

reside in biliary tree; burrow through liver; RUQ pain

can also cause cholioangiocarcinoma

you get these from undercooked fish; predominate in SE asia

9
Q

diphyllobothrium latum life cycle/vector

A

fish tapeworm!

humans eat contaminated fish w/larvae in their muscles

larvae(plerocercoids) migrate/attach to intestinal wall where adults develop

adults make eggs which pass in stool; if eggs make it to freshwater, cycle starts over

10
Q

symptoms w/fish tapeworm(diphyllobothrium latum)

diagnosis?

treatment?

A

non-specific abdominal pain; usually asymptomatic

can have a vit b12 deficiency

eggs found in stool to diagnose

treat with niclosamide or praziquantel

11
Q

life cycle/vectors of *taenia solium/saginata *

A

t. solium/saginata are pork/beef tapeworms

  • Embryonated eggs and/or gravid proglottids are eaten by pigs/cattle
  • Embro hatch in gut and head to muscle via circulation/lymph
  • Develops into a cysticercus in the muscle
  • Humans eat undercooked meat and ingest **cysticerci **which pop their inverted head out and attach to intestinal mucosa; mature in 2 months
    • Humans can also directly inoculate themselves with eggs and get cysticercosis just like the pigs/cattle! –> muscle brain problems
12
Q

differentiate taeniasis vs cysticercosis infections

A

Pork/beef tapeworms - t. solium and saginata

taeniasis is where humans ingest contaminated meat containing larvae

  • adult worms develop in intestines causing little damage

cysticercosis is where humans directly ingest eggs and their muscles/brain get infected

  • seizures, hydrocephalus, brain dmg(neurocysticercosis), death
  • leading cause of adult epilepsy(8-10% of ER seizures in LA and houston)
  • seen in immigrant population(pig farmers, poverty, poor sanitation)
13
Q

treatment for pork/beef tapeworms(taenia)

A

niclosamide or praziquantel

for neurocysticercosis: use albendazole/praziquantel for 1-4wks

14
Q

echinoccus granulosum causes what type of disease?

manifestation?

A

hyatid cysts

large fluid filled bladders develop over years which contain millions of scolices

cysts develop most commonly in liver, lung; more rarely bones/cns

rupture causes a severe anaphylactic reaction

transmitted via dog/sheep rearing areas;

15
Q

how to treat hyatid cysts?

A

inactivate cyst w/hypertonic saline then remove surgically

albendazole/mebendazole in high doses; long term therapy