non-diarrheal non-invasive parasitic infestations: flatworms/cestodes Flashcards Preview

Micro > non-diarrheal non-invasive parasitic infestations: flatworms/cestodes > Flashcards

Flashcards in non-diarrheal non-invasive parasitic infestations: flatworms/cestodes Deck (59):
1

tapeworm spp.

Taenia saginata, T. solium
Diphyllobothrium datum
Hymenolepis nana

2

tapeworms are ??

long, segmented worms:
head- scolex
neck
segmented body: proglottids
entire "tape: strobila
*monoecious, of Cestoda class*

3

Cestoda class

Tenia, Diphyllobothrium, Hymenolepis, Dipylidium, Echinococcus, Spirometra

4

tapeworm larvae attach via the ?? in the ?? and dev. into adult worms

require 1 or more ??

scolex (head)
small intestine

intermediate hosts

5

tapeworm infection typ. transmitted how??

how so??

fecal-oral or ingestion of contaminated, undercooked meat

eggs pooped from host-->into environ.-->eaten by interned. host-->hatch and larvae enter host tissue and encyst-->then primary host eats the intermediate host meat and gets the cyst

6

humans are the primary host for ??
thus ??? necessary to sustain life cycle

Taenia, Diphyllobothrium, Hymenolepis, Spirometra
human fecal contamination of the environment

7

?? only cestodes for which humans can function as both primary and intermediate host,
therefore ??? is possible

Hymenolepis spp. and Taenia solium

autoinoculation

8

in ??? cestode spp, humans function as intermediate hosts
?? exist within tissue and migrate thru diff organ systems

Echinococcus spp., Spirometra spp., Taenia multiceps
larvae

9

Taenia solium hosts

primary: humans (stays in gut)
intermediate: pigs, humans*, dogs, cats, sheep (can go anywhere)

10

Taenia saginata hosts

primary: humans
intermediate: cattle

11

Diphyllobothrium hosts

primary: humans
intermediate: fish

12

Hymenolepis hosts

primary: humans
intermediate: H. nana has none (autoinoculation: fecal-oral)
H. diminuta- rodents

13

D. caninum hosts

primary: humans, dogs, cats
intermediate: fleas on dogs/cats

14

Echinococcus hosts

primary: dogs
intermediate: humans, sheep, cattle, goats, horses, camel

15

Spirometra hosts

primary: humans
-I believe humans function as intermediate host as well

16

Taenia multiceps hosts

primary: humans?
intermediate: hares, rabbits, squirrels, humans (rarely)

17

many cestode infestations are ?? and depend on ??

asymptomatic, worm burden

18

beef tapeworm ??
pork tapeworm ??

acquired how?

T. saginata
T. solium

ingestion of cysticerci larvae in improperly cooked meat

19

T. sag and T. sol larvae are released when ?? and attaches to ?? via ??

adult worm may be how long ??

during digestion, attaches sm. intestine via the scolex


may be 5-8 meters! T. sag>T. sol

20

as Taenia proglottids filled with eggs grows, they break off and migrate thru the ??

large intestine, rectum, anus-->exterior

T. saginata may be pooped out or exit by themselves

21

the cycle continues if...
?? are released during digestion and hatch into ?? in the sm. intestine then ??

proglottid is eaten by animals
eggs, larvae
then actively penetrate sm. intestine of pig/cow and migrate via blood to all organs, may be eaten by humans

22

cysticercosis happens when humans eat ??? of what cestode??
therefore transmission via ??


the ?? then penetrate the intestinal wall (like in intermed. host) and encyst in host tissue such as ??

ova of *T. solum* rather than larval form

fecal contam. of food, water and poor personal hygiene (auto infection) -NOT eating meat

larvae
CNS, muscle, eye
*much more serious than tapeworm infestation!

23

D. latum (fish tapeworm) cycle

eggs must ??


fish ingests ?? and the ?? penetrates the sm. intestine and lives in muscle and develops into ??



enter fresh water for cycle to continue-->intermediate stages

infected water flea, perocercoid larva
pleurocercoid larva (infective stage for humans)

24

Diphyllobothrium latum infects humans when ??


D. latum absorbs ??? in human host and big one can cause ??

eating raw/undercooked fish with larva
cycle starts over

Vitamin B12-->megaloblastic anemia

25

Hymenolepis nana (Dwarf tape worm) are ?? when pooped out

immediately infective
can't survive more than 10 days in external environment

26

H. nana eggs are eaten by ?? and develop into ?? which can ?? and develop into ?? in the small intestine

an arthropod(beetle, flea) intermediate host?
cysticercoids, can infect humans/rodents when eaten and dev. into adults in sm. intestine

27

H. nana var. fraterna

infects rodents, arthropods as intermediate hosts

28

H. nana eggs ingested via ??
and release their ?? which ?? and dev. into ??

contaminated food or water or feces-contam. hands
oncospears (hexacanth larvae) --> penetrate the intestinal villus and develop into cysticercoid larvae

29

when the ?? rupture , the H. nana cystercercoids go back to the ?? and do what ??

villus
intestinal lumen, evaginate their scoleces, attach to intestinal mucosa and dev. into adults that live in the ileal portion of the sm. intestine producing gravid proglottis

30

H. nana ?? are pooped out when release from proglottids through its ?? or when proglottids ?? in the sm. intestine

eggs
genital atrium
disintegrate

31

alternatively, H. nana eggs release their ?? which penetrates the villus, continuing the ?? without passage through external environment
name of this cycle? which allows the infection to ??

hexacanth embryo
infective cycle

internal autoinfection, persists for years (vs 4-6 wks)

32

Canid Echinococcus spp
E. granulosus causes a ?? produces eggs that are passed with ??

typical tapeworm inf.

dog poop

33

in the intermediate host, E. granulosus eggs hatch into ?? that travel through blood and form ?? in host tissue
what organs?

how big??

oncosphere larvae
hydatid cysts
liver, brain, lungs, NOT subcutaneous tissue

size of a softball or basketball! and may contain sev. smaller "balloons" w. in main cyst
make inf. animals easier prey (i.e. moose)

34

T. saginata risks/regions

beef
Central Asia, near East, Central and East Africa
alternative intermediate hosts (i.e. exotic animals besides cattle: llamas, giraffes, buffalo, etc.)

35

T. solium risks/regions

pork
Mexico, Central and South America
also Southern Europe, Africa, SE Asia, India, Phillipines
-like everywhere

36

D. latum risks/regions

fish
N. America, Siberia, Europe, Scandinavia, Baltics, Japan, Chile
alternative definitive hosts (besides humans): seals, cats, bears, minks, foxes, wolves, etc.)

37

?? is the most commonly dx tapeworm inf. in the US

affects who most commonly??


transmitted how??

H. nana

school-aged, institutionalized kiddos in SE US (day care)
children in dry, warm regions of developing countries

fecal-oral, person-person may occur: think mt. range; it propagates

38

Hymenlepis diminuta, mostly a cestode of ??
humans are (rarely) infected by ingesting mealworms/grain beetles that contain ??
in what foods??

rodents

cysticercoid larvae
dried grains, cereals, flour and dried fruit

39

Eichinococcus spp. are cestodes that inhabit ??
?? are intermediate host
?? are at high risk

the small bowel of canids (dogs, wolves, foxes)
humans
sheepherders

40

tapeworm inf. are typically ??
otherwise presentation:

asymptomatic
vague: GI discomfort, weakness, dizziness, salt craving, diarrhea
uncontrollable screaming (i.e. find proglottids of T. saginata in poop or on own)

41

T. solium
symps assoc. with ?? depend on ??
most sev. if in ??


cysticercosis, worm burden and location
eye (blindness) or brain (neurocysticercosis: seizures-70%)

42

where is neurocysticercosis prevalent??

Mexico, Central and South America
*immigrant pop*

43

D. latum presentation

if large worm/several worms-->
pernicious-like anemia (vit B12 def)

44

if Echinococcus (canine tape worm) cysts rupture, may cause ??

most serious complication that has a 90% fatality rate @ 10 yrs??

?? can happen in response to worm Ag suddenly release into circulation with cyst rupture

fever, pruritus, urticaria, eosinophilia, anaphylaxis


untx symptomatic liver involvement

erosion of surrounding tissue, systemic anaphylaxis (type 1 hypersensitive)-->mediated by elevated eosinophils and IgE

45

dx cestodes (tapeworm) infection via finding

adult orgs in intestine, ova/proglottid in fecal sample

46

dx cysticercosis imaging

CT and MRI may show calcified lesions in subarachnoid or intraventricular spaces
-but almost any brain/SC region could be affected

skeletal muscle encystment

47

dx cysticercosis labs

blood: detect Abs to worm Ags- ELISA (definitive)
or dx if larvae are surgically removed

48

intestinal tapeworm tx

Niclosamide: uncouples oxidative phos. in tapeworm
or
Praziquantel: interferes with adenosine uptake

49

cysticercosis tx

Albendazole
(no anticonv. or dexameth interactions- given for CNS complaints)

use corticosteroids (dexamethasone) to reduce inflammation during tx

sx may be required

50

Echinococcus dx

imaging (US, MRI, CT)
serology to comfirm (ELISA, Western blot)

51

issues with cyst removal in Echinococcus tx

accidental rupture-->anaphylaxis
accidental spread of larvae-->daughter cysts
secondary bac infection

52

Echinococcus tx

sx: aspiration and instillation of cysticidal agents and removal of cyst

albendazole, mebendazole
response depends on cyst size and location

53

T. saginata ppx

cook beef, prev. human fecal contam of pastures
prolong deep freezing to kill cysticerci

54

T. solium ppx

rare in US, typ. from Latin America, Asia
personal hygiene important for cysticercosis (self-inf or person-person)
mass tx w. praziquantel/niclosamide in endemic areas

55

D. latum ppx

cook fish throughly

56

Echinococcus ppx

de-worm/tx dogs
wash hands throughly
avoid unwashed/raw veggies where canines poop

57

FLUKES (non-cestode): intestinal trematodes


infected how ??
what region ??

flat, hermaphroditic worms, few mm-cm
>40-50 mil ppl ww

food-borne
SE Asia

58

most common Flukes/trematodes spp

*Fasciolopsis buski*
Heterophyes heterophys
Metagonimus yokogawai
Echinostoma spp.

59

Fluke infection presents like ??

a malabsorptive illness
eat environmentally incubated cysts (water chestnuts)
can't put on muscle mass

Decks in Micro Class (61):