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135 Cards in this Set
- Front
- Back
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Latin name for tapeworm?
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Cestode
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What are in the Phylum platyhelminthes?
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Flatworms
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What are commonalities of platyhelmenthes?
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bilateral symmetry
acoelomate mostly hermaphroditic |
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What classes of worms are in the platyhelminthes?
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Turbellaria (free living worms like planarians)
Trematodes (flukes) cestodes (tapeworms) |
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What are the 2 orders of the cestodes?
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cyclophyllidea (taenia, hymenolepis, diphylidium, echinococcus)
psuedophyllidea (dipyllobrothrium, spirometra) |
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Was is unique about the order cyclophyllidea?
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Parasitize humans
Have scolex with suckers Have genital pore on the side |
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What is unique about the order pseudophyllidea?
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Have a scolex called a borthrea
Have a genital pore in the middle |
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Generalizations about cestode lifecycle?
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Foodborne parasites
Adults live in intestine of definitive host Disease is normally benign Larval stages live in tissue of intermediate host LARVA cause most severe disease manifestations |
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What are the body parts of the cestodes?
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Scolex (head)
Strobila (body) Proglottid (segments of the body -- hermaphroditic) |
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How long can tapeworms get?
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Up to 25 METERS
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What are the parts of the proglottid?
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Have male and female organs (hermaphroditic)
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What does acoelomate mean?
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Feature of flatworms
Organs don't float freely (like in a coelum)...but are embedded in organs |
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Does scolex damage the intestine when attaching?
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No
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How do tapeworms fertilize eggs?
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Hermaphroditic -- can self fertilize
Can also cross fertilize if >1 around |
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Do tapeworms have a cuticle?
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No, a tegement
Can absorb nutrients Resists digestion |
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What is the vitellaria of a tapeworm
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An organ that produces the egg shell (part of the proglottid)
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What happens to tapeworm uterus as it grows?
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Creates branches as it becomes gravid
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What are the layers of proglottid on cross section?
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Tegement (skin)
Thick muscle layer Thin muscle layer Medulary parenchyma (B) excretory canals, with nerve canal running alongside |
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What are calcareous corpusles?
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Diagnostic featrures of cestodes
Little spots found on cross section |
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List the 6 adult cestodes that commonly parasitize humans
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Taenia solium (pig tapeworm)
Taenia saginata (beef tapeworm) Hymenolepsis diminuta (rat tapeworm) Hymenolepsis nana (dwarf tapeworm) Diphylidium caninum (dog tapeworm) Diphylloborthrum (fish/broad tapeworm) |
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What is a bothrea head?
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A loop shaped scolex
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How do humans get pig and cow tapeworm?
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Eat their encysted flesh
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Endemic foci of taenia saginata?
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Grasslands of subsaharan africa/ethiopia
Northern mexico, argentina China, se asia |
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Describe taenia saginata
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Beef tapeworm
Adult 4-6m long 1000-2000 proglottids 4 prominent suckers, no rostellum/hooks Eggs 30-40um, thick stirated shell, contains hexacanth embryo with prominent hooks Proglottid 12mmx12mm with alternating lateral genital pores Gravid proglottid - 15-30 unterine branches, up to 100,000 eggs |
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Does scolex of Taenia saginata have hooks?
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No
But the exacanth embryo does |
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What is diagnostic of taenia sagniata?
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Many branched uterus in proglottid (15-30 branches)
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What is unique about taenia saginata egg?
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Has hooks, but the adult scolex does not
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Describe taenia solium morphology
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Pig tapeworm
Adult 2-6m long, up to 1000 proglottids Scloex: 4 suckers, 2 rows of hooks on rostellum Egg with hexacanth embryo with hooks Prolottid: 12x12m, few uterine branches, up to 40,000 eggs |
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How to tell egg of pig from beef tapeworm?
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Can't
Both with hexicanth embryo with prominent hooks |
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How to tell scolex of pig from beef tapeworm?
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Beef tapeworm no hooks
Both with 4 suckers |
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How to tell proglottid of pig from beef tapeworm?
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Pig with fewer lateral uterine branches (7-13 vs. 30)
Pig with fewer eggs (40,000 vs 100,000) |
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Where find taeia solium?
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everywhere people eat pigs
in USA, common in S. cal |
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How many pig tapeworms found per host?
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1 -- thus the name Taenia solium (solo)
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What is the thing found on meat that indicates larval infestation with taenia?
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cysticercus
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Where are cysticerci commonly found?
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Tongue of live pigs
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What is the treatment of taenia infection?
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Praziquantel
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If you poop out a proglottid, how to tell beef vs. pig?
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Beef is normally single proglottid (motile)
Pork normally strops of proglottids |
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What is the pathology of adult tapeworms in humans (taenia)
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Normally nothing
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What is the most common human cestode infection?
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Hymenolepis nana
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What is unique about hymenolepsis nana infection in humans?
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Eggs can internally autoinfect host (or ingest and autoinfect)
Don't need to leave host to reproduce May get heavy infestations, esp in kids |
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What is the symptom of Hymenolepsis nana infection in humans?
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Large infestation
Can cause abd pain |
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What are the hosts of hymenolepsis nana?
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Humans
Rats |
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What is unique about the Hymenolepsis nana lifecycle?
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Human sheds eggs in feces, eaten by arthropod, which is then eaten by human (or rat)
Humans can also directly ingest eggs and reinfect Humans can autoreinfect inside intestine |
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Describe Hymenolepis nana proglottids?
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Wide and short ("craspedote form)
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Describe hymenolepsis nana eggs
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Not striated
Embryo with hooks |
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Describe hypenolepsis diminuta?
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Bigger than H. nana (despite name)
SImilar lifecycle to H. nana, but no autoinfectino...requires arthropod to eat egg, form cystercerci...which is then ingested by rat or human |
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What tapeworms are spread to humans and rats by eating arthropods with cystercerci?
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Hymenolepis nana and diminuta
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What is the difference between H. nana and H. diminuta scolex?
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H. nana: hooks and 4 suckers
H. diminuta: no hooks, 4 suckers |
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Describe hymenolepsis nana and diminuta proglottids?
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Wider than long
Single one-sided genital pore 3 rounded testes, bilobed ovary |
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How to tell H. nana egg from H. diminuta?
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H. diminuta rounder, larger
H. nana smaller, ovoid, thicker shell |
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Another name for H. nana?
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Dwarf tapeworm
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Anothe name for H. diminuta?
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Rat tapeworm
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Which has a higher parasite burden....H nana or diminuta?
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H. nana -- as can autoinfect
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What is the natural host of Dipylidium caninum?
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Dog
Human's occasional |
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How big D. caninum tapeworm?
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15-75cm
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Describe D. caninum scolex:
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4 suckers
armed rostellum |
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Describe D. caninum proglottid?
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Mobile, 2.3x0.8cm (longer than wide)
5-30 eggs each Can crawl out of anus Passed in 1-3 units |
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Unique about D. caninum eggs?
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Found in egg packets in poop
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What is Diphyllobothrium latum?
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Fish tapeworm
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Describe lifecycle of fish tapeworm?
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Adult in human...proglottid releases eggs in poop...poop in water...eggs embryonate...develop into coracida....eaten by crustacean...procercoid larva in crustacean....eaten by fish...into fish muscle...up food chain....human eats undercooked fish...ta da
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How long is a fish tapeworm?
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4-10 meters
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What kind of scolex does fish tapeworm have?
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Bothria (loop shaped)
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Describe fish tapeworm proglottids?
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Wider than long
Numerous testes and vitellaria Bilobed ovary Rosette shaped gravid uterus |
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Describe fish tapeworm egg
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Has an operculum -- a cap that pops open to let out the larva
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What is an operculum?
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Cap on an egg that pops open to let larva out (e.g. fish tapeworm)
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Sx of tapeworm infestations?
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Usually little to no dz
Eosinophilia (moderate) Fish tapeworm rarely causes B12 deficiency |
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Treatment of tapeworms?
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Pig, beef and fish: Praziquantel 10mg/kg
H. nana, H. diminuta, D. aninum: 25mg/kg Niclosamide 2g adult, 1g small children |
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4 larval cestodes that parasitize humans
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Taenia solium
Taenia multiceps Echinococcus spp Spirometra spp * Hymenolepsis nana cysticercoid |
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Do beef tapeworm larvae infest humans
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No
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How do humans get larval tapeworm forms?
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If humans ingest tapeworm eggs (from human feces)
FECAL ORAL |
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Do you have to eat pigs to get larval cysticercosis?
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NO
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What is cystercercosis?
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Larval form of pig tapeworm
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Where can cystercerci be in humans?
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Any tissue/organ
Commonly brain, skeletal muscle, peritoneum, sq tissues |
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What is neurocystercercosis?
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Pig tapeworm larvae in CNS
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Common presentation of neurocystercercosis?
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Seizure
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Pathogenesis of cysticerci (pig tapeworm larvae)
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Larva live up to 5 years
Little inflammation DEATH of larva causes inflamation and sx Body reacts with lymphocytes, plasma cells, eosinophils Cellular rxn destroys parasite/leaves calcified nodule |
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Can you see cystocerci on xray?
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Yes, when calcified (unlike trichonella)
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What causes muscular pseudohypertrophia?
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Musclular cystocerci
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What does the taenia solis cystocercus look like?
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Cyst with 1 protoscolex
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Can taenia solis cystocercus invade the eye?
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Yes
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Neuro sx of neurocysticercosis
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Seizure/mass effect
Hydrocephalis Giant subarachnoid cysts Racemic (looks like tumor) of parasitic tissue - solid |
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How to dx cysticercosis?
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Find a cystercercum
Serology (good if >1 lesion) |
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Rx for cystercercosis
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Anticonvulsants
Steroids ?Antiparasitic -- maybe if viable cysts or evidence increased ICP Shunt if obstruction Surgical resection |
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What is coenurosis?
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Infection with larval cestodes of Taenia multiceps and Taneia serialis tapeworms
Dogs/canine defitintivie hosts Intermediate hosts sheep/herbivores/humans Found worldwide |
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What is a gid?
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The finding of coenurosis in larval infected sheep
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How do humans get coenurosis?
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Dogs eat infected sheep, etc.
Get tapeworm Pass eggs in stool Humans eat eggs, get larval stage |
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WHere are human forms of coenurosis found?
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Worldwide, but mostly africa
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What do cysts of coenurosis look like?
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Cyst with mutlipe proscolices
Taenia multiceps have scttered proscolices Taenia serialis have clustered proscolices |
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What is coenurus
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Cyst with multiple proscolices
Uncommon in humans == in humans, normally no proscolices |
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What is hydatid disease?
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Infection of larvae of carnivore tapeworms
Echinococcus granulosis Echinococcus multilocularis Echinococcus volgeli E. aligarthurs |
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What are the forms of hydatid disease?
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Cystic, unilocular
Alveolar Polycystic |
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What causes unilocular hydatidosis?
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Worldwide where farm dogs used (sluvatic hosts -- wild dogs, kangaroos)
Humans incidental intermediate host |
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Describe the worm of Echinococcus granulosis
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5mm tapeworm, found in dog small intestine, with 2 proglottids
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Where in world is Hydatid dz?
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worldwide, but temperate common
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Where does hydatidosis fro echinococcus granulosis live in humans?
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Cysts in liver and lungs
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Describe a hydatid cyst
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Large cyst
Has initial brood capsule with protoscolices Also hydatid sand (free floating protoscolices) Also daughter cysts Has an external laminated membrane -- hefty wall with inner parasite/outer firbrous host materials |
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Describe the hydatid cyst laminated membrane
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Inside: Germinal layer (makes protoscolices)
Middle lamellar layer Outer host tissue fibrous layer |
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Name the 3 types of taenid cysts
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Cysticercus
Coenurus Hydatid |
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If a dog eats a hydatid cyst, what happens?
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Gets TONS of tapeworms
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What is hydatid sand?
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The free floating protoscolices of echinococcus granulosis in a hydatid cyst
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Where are hydatid cysts found?
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Follow bloodstream
Commonly liver (60%), lungs (20%), kidney (3%) Bone 2%, CNS 1% 60% asx 2% fatal |
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If you see a calcified hollow mass in liver, what might this be?
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Hydatid cyst
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Sx of hydatid cyst?
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Mass effects, esp in liver/lung
Leaking fluid: secondary infections/abscess Leak from lung: salty taste Recurrent allergic sx Pathologic fx in bone |
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What larval dz can lead to anaphylaxis?
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Hydatid dz...if cyst ruptures
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Complication of hydatid cyst rupture?
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Anaphylaxis
Fluid migrates and forms new cysts Seconday infection |
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CXR sign of hydatid cyst rupture?
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S-shaped lesion in lung
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Is there serology for hydatid dz?
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Yes
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How to rx hydatid dz?
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Surgical removal (risk spread)
PAIR technique (percutaneous aspiration, injection and reaspiration) Albendazole |
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What is PAIR techniques used for?
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Treatment of hydatid dz
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Where is alveolar hydatid dz found?
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Northern hemisphere (europe/asia/america)
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What causes alveolar hydatid dz?
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E.chinococcus multilocularis
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What is the definitive host of echinococcus multilocularis?
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Dogs/wild
Intermediate hosts -- small rodents, humans (incidental) |
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How long is the incubation period of E. multilocularis in humans?
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Long 5-15 years
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How does E multilocularis injure human tissue?
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InBuds from inside out (exogenous budding)
Germina membrane extends into tissue in neoplastic fasion In humans, no proscolices seen -- just the evergrowing germinal layer Normally, germinal layer stops once protoscolex produced |
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Describe human alveolar hydatid infection
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Highly invasive due to exogenous budding of germinal layer
Usually in liver Can spread to lungs |
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How treat alveolar hydatid dz
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Surgery, but difficult
Long term albendazole/nitazoxanide helps PREVENTION |
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What dz might you get from wild dog furs?
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Alveolar hydatid infection (from animal poop, therefore egg, contamination from Echinococcus multilocularis)
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How to prevent hydatid dz?
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Deworm dogs
Vaccinate sheep Don't feed dogs raw innards Don't kiss your dog |
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What is sparganosis?
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An infection of larvale plerocercoids of the spirometra spp
Humans incidental /dead end hosts ormally food borne via infected copepod or ingesting raw paratenic host (frog, fish, snakes) Also via mucous membranes -- like frog poltices Larval form migrates |
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What can you get from eating frogs/snakes/fish or icing your eye with a cold frog?
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Sparganosis
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What is the lesion of sparganosis?
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Sparganum - a larva curled up in host tissue in the form of a plerocercoid
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What do echinococcus spp cause?
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Hydatid dz
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What causes coenurosis?
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Taenia multiceps and serialis
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What causes cysticercosis?
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Taenia solium
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Where do tapeworms attach?
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Small intestine
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How to get larval tapeworms?
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Ingest eggs
Onchosphere penetrate directly through intestinal wall in autoinfection |
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What is gid?
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CNS condition of sheep infested with T. muticeps larvae, coenuri in CNS
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Are there serological tests for coenurosis?
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No
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Treatment of coenurosis?
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Surgical -- preop dx unlikely
Mebendazole - ineffective, No studies on other agents |
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What larval dz may be found in NZ (and other sheepherding countries?)
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Hydatid disease from echinococcus granulosis
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What larval dz might you catch from a fox?
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Echinococcus multilocularis (fox the most definitive host, then dogs, cats, coyotes, wolves; intermediate hosts are rodants)
Humans get by eating feces (e.g. plans contaminated by fox poops, digs, etc.) |
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You find a spongy, porous, irregular cavity filled jelly filled cyst in a liver...what might this be?
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Alveolar hydatid dz...from Echinococcus multilocularis
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What causes polycystic hydatid dz
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Central/south america
Echinococcus oligarthus Echinococcus vogeli Dog hosts Rodent intermediate hosts Lung/liver |
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How big can a spargana grow?
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From Spirometra tapeworms -- larval form
Up to 14 inchies! In eye -- blindness In subdermal -- painful lumps Normally found in explor. surgery |
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Treatment of sparganosis?
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Praziquantel maybe 120mg/kg over 2d
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