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

Question 1

tapeworm spp.

Answer 1

Taenia saginata, T. solium
Diphyllobothrium datum
Hymenolepis nana

Question 2

tapeworms are ??

Answer 2

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

Question 3

Cestoda class

Answer 3

Tenia, Diphyllobothrium, Hymenolepis, Dipylidium, Echinococcus, Spirometra

Question 4

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

require 1 or more ??

Answer 4

scolex (head)
small intestine

intermediate hosts

Question 5

tapeworm infection typ. transmitted how??

how so??

Answer 5

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

Question 6

humans are the primary host for ??

thus ??? necessary to sustain life cycle

Answer 6

Taenia, Diphyllobothrium, Hymenolepis, Spirometra

human fecal contamination of the environment

Question 7

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

Answer 7

Hymenolepis spp. and Taenia solium

autoinoculation

Question 8

in ??? cestode spp, humans function as intermediate hosts

?? exist within tissue and migrate thru diff organ systems

Answer 8

Echinococcus spp., Spirometra spp., Taenia multiceps

larvae

Question 9

Taenia solium hosts

Answer 9

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

Question 10

Taenia saginata hosts

Answer 10

primary: humans
intermediate: cattle

Question 11

Diphyllobothrium hosts

Answer 11

primary: humans
intermediate: fish

Question 12

Hymenolepis hosts

Answer 12

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

Question 13

D. caninum hosts

Answer 13

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

Question 14

Echinococcus hosts

Answer 14

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

Question 15

Spirometra hosts

Answer 15

primary: humans

- I believe humans function as intermediate host as well

Question 16

Taenia multiceps hosts

Answer 16

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

Question 17

many cestode infestations are ?? and depend on ??

Answer 17

asymptomatic, worm burden

Question 18

beef tapeworm ??
pork tapeworm ??

acquired how?

Answer 18

T. saginata
T. solium

ingestion of cysticerci larvae in improperly cooked meat

Question 19

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

adult worm may be how long ??

Answer 19

during digestion, attaches sm. intestine via the scolex

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

Question 20

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

Answer 20

large intestine, rectum, anus–>exterior

T. saginata may be pooped out or exit by themselves

Question 21

the cycle continues if…

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

Answer 21

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

Question 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 ??

Answer 22

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!

Question 23

D. latum (fish tapeworm) cycle

eggs must ??

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

Answer 23

enter fresh water for cycle to continue–>intermediate stages

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

Question 24

Diphyllobothrium latum infects humans when ??

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

Answer 24

eating raw/undercooked fish with larva
cycle starts over

Vitamin B12–>megaloblastic anemia

Question 25

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

Answer 25

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

Question 26

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

Answer 26

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

Question 27

H. nana var. fraterna

Answer 27

infects rodents, arthropods as intermediate hosts

Question 28

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

Answer 28

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

Question 29

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

Answer 29

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

Question 30

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

Answer 30

eggs genital atrium disintegrate

Question 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 ??

Answer 31

hexacanth embryo infective cycle internal autoinfection, persists for years (vs 4-6 wks)

Question 32

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

Answer 32

typical tapeworm inf. dog poop

Question 33

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

Answer 33

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)

Question 34

T. saginata risks/regions

Answer 34

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

Question 35

T. solium risks/regions

Answer 35

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

Question 36

D. latum risks/regions

Answer 36

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

Question 37

?? is the most commonly dx tapeworm inf. in the US affects who most commonly?? transmitted how??

Answer 37

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

Question 38

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

Answer 38

rodents cysticercoid larvae dried grains, cereals, flour and dried fruit

Question 39

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

Answer 39

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

Question 40

tapeworm inf. are typically ?? | otherwise presentation:

Answer 40

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

Question 41

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

Answer 41

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

Question 42

where is neurocysticercosis prevalent??

Answer 42

Mexico, Central and South America | *immigrant pop*

Question 43

D. latum presentation

Answer 43

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

Question 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

Answer 44

fever, pruritus, urticaria, eosinophilia, anaphylaxis untx symptomatic liver involvement erosion of surrounding tissue, systemic anaphylaxis (type 1 hypersensitive)-->mediated by elevated eosinophils and IgE

Question 45

dx cestodes (tapeworm) infection via finding

Answer 45

adult orgs in intestine, ova/proglottid in fecal sample

Question 46

dx cysticercosis imaging

Answer 46

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

Question 47

dx cysticercosis labs

Answer 47

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

Question 48

intestinal tapeworm tx

Answer 48

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

Question 49

cysticercosis tx

Answer 49

Albendazole (no anticonv. or dexameth interactions- given for CNS complaints) use corticosteroids (dexamethasone) to reduce inflammation during tx sx may be required

Question 50

Echinococcus dx

Answer 50

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

Question 51

issues with cyst removal in Echinococcus tx

Answer 51

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

Question 52

Echinococcus tx

Answer 52

sx: aspiration and instillation of cysticidal agents and removal of cyst albendazole, mebendazole response depends on cyst size and location

Question 53

T. saginata ppx

Answer 53

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

Question 54

T. solium ppx

Answer 54

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

Question 55

D. latum ppx

Answer 55

cook fish throughly

Question 56

Echinococcus ppx

Answer 56

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

Question 57

FLUKES (non-cestode): intestinal trematodes infected how ?? what region ??

Answer 57

flat, hermaphroditic worms, few mm-cm >40-50 mil ppl ww food-borne SE Asia

Question 58

most common Flukes/trematodes spp

Answer 58

*Fasciolopsis buski* Heterophyes heterophys Metagonimus yokogawai Echinostoma spp.

Question 59

Fluke infection presents like ??

Answer 59

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