Micro444 Cestodes

Front 1

Describe symptoms and etiology of Taeniasis.

Back 1

T. saginata (beef) + T. solium (pork)

asymptomatic or mild abdominal discomfort

gravid proglottids/eggs in feces

Front 2

Morphological differences between T. saginata and T. solium?

Back 2

T. saginata larger (5-20m long), more uterine brances, unarmed rostellum

T. solium 3-8m long, armed rostellum

Front 3

Route of infection for taeniases?

Back 3

ingest larvae in undercooked meet

Front 4

Definition of intermediate host in context of cestodes?

Back 4

host where LARVAL FORM is found

Front 5

Definition of definitive host in context of cestodes?

Back 5

host where ADULT is found

Front 6

Intermediate and definitive hosts of T. saginata?

Back 6

intermediate = cattle

definitive = human

Front 7

Intermediate and definitive hosts of T. solium?

Back 7

intermediate = pigs

definitive = human

Front 8

Intermediate and definitive hosts of Echinococcus granulosus?

Back 8

intermediate = ruminant animals; humans (accidental)

definitive = dogs/wolves

Front 9

Intermediate and definitive hosts of Hymenolepis nana?

Back 9

intermediate = grain beetles, humans, rodents

definitive = humans, rodents

intermediate host not necessary for completion of life cycle

Front 10

Intermediate and definitive hosts of Hymenolepis nana?

Back 10

intermediate = grain beetles

definitive = humans, RATS

Front 11

Route of infection for Echinococcus granulosus?

Back 11

ingest ova from dog/wolf feces

Front 12

Route of infection for Hymenolepis nana?

Back 12

1. ingest ova (fecal-oral route)
2. internal autoinfection
3. ingest grain beetles w/cystecercoids

Front 13

Route of infection for Hymenolepis diminuta?

Back 13

ingest grain beetles w/cystecercoids

Front 14

Route of infection for Diphyllobothrium latum?

Back 14

ingest PLEROCERCOID larvae in undercooked freshwater fish

Front 15

Morphology of Taenia spp. ova?

Back 15

yellow-brown, round w/radial striations

35-65um

like a ravioli

hexacanth hooks

Front 16

Morphology of Echinococcus ova?

Back 16

same as Taenia

round ravioli thing with hexacanth hooks

Front 17

Morphological difference between Hymenolepis nana and diminuta ova?

Back 17

H. nana: 40-50um, POLAR FIBRILS in space between embryo/egg case, hexacanth hooks

H. diminuta: larger, no polar fibrils, hexacanth hooks

Front 18

Morphology of D. latum eggs?

Back 18

operculate: lidded (subtle--look closely)

knob on other end

brown, 40 x 60 um

Front 19

Morphology of Echinococcus granulosus adult?

Back 19

only three segments: scolex, immature proglottid, gravid proglottid

3-6mm long

armed rostellum, 4 suckers

Front 20

Morphology of D. latum adult?

Back 20

3-10m long (up to 25m!) largest human tapeworm

NO SUCKERS--2 grooves instead

"rosette" shaped gravid proglottids, short but wide, flat segments

Front 21

Intermediate and definitive host of Diphyllobothrium latum?

Back 21

Intermediate: copepods (procercoid larvae), fish food chain (plerocercoid)

Definitive: human (adults)

Front 22

Etiology of cysticercosis in humans?

Back 22

ingestion of T. solium OVA

ingest larvae (cystecerci) --> simply taeniasis.

Front 23

Symptoms of cysticercosis?

Back 23

formation of cystecerci (scolex + bladder larvae) like tumors

widespread tissue invasion: eyes, subcutaneous, liver

invade BRAIN --> dementia

one egg --> one cyst

Front 24

How to dx taeniasis?

Back 24

gravid proglottids/eggs in feces

Front 25

How to dx cysticercosis?

Back 25

Radiology: CT Scan/MRI shows calcifications, "swiss cheese" lesions in brain

Immunoblotting of blood only

Front 26

Etiology of Echinococcosis?

Back 26

ingest egg --> formation of hydatid cysts, slow but constant tumorlike growths

liver, lung, brain; METASTASIS

germinal layer --> daughter cyst filled w/hydatid sand (protoscolices)

Front 27

How to dx Echinococcosis?

Back 27

Radiology/Ultrasound: see sharply demarcated cluster of cysts, "snowglobe" effect of free-floating hydatid sand in cyst.

ELISA assay, Serology for liver infections

Front 28

Why is removal of hydatid cysts risky?

Back 28

Hydatid sand may be released into blood and seed a whole bunch of new cysts

--> inject cyst with ethanol first to kill, then remove

Front 29

Where is Echinococcosis most prevalent?

Back 29

Hopi indians, sheep raising cultures

dogs prone to infection b/c eat innards of slaughtered sheep (sheep = intermediate host)

Front 30

Which Echinococcosis cysts are easiest to detect? Hardest to detect?

Back 30

easiest: liver

hardest: lung, brain

sensitivity of diagnostic tests depends on location of cysts.

Front 31

How do cysticerci differ from hydatid cysts?

Back 31

Hydatid cysts have GERMINAL LAYER --> can bud off daughter cysts and metastasize

Cysticerci lack germinal layer and are not as malignant; severity depends on #ova ingested

Front 32

Symptoms of infection w/Diphyllobothrium latum?

Back 32

pretty harmless; abdominal pain at most

some N. American spp may cause B12 deficiencies --> anemia

Front 33

Infectious form of Diphyllobothrium latum?

Back 33

plerocercoid larva in undercooked fish

Front 34

What population is especially prone to infections by Hymenolepis nana?

Back 34

Children b/c they tend to mess around in the dirt with bugs

Front 35

Symptoms of infestation with H. nana?

Back 35

often asymptomatic if ingest LARVA (cysticercoid larva)

if ingest ovum, cysticercoids form in intestinal villi --> abdominal cramping, autoinfection possible (prolonged infection)

Front 36

Symptoms of infestation by Dipylidium caninum?

Back 36

n/a or light symptoms (abdominal discomfort)

"rice grain" appearance of motile gravid proglottids excreted in feces. resembles maggots.

Front 37

Which is the only worm in which single eggs are uncommon in feces of infected host?

Back 37

Dipylidium caninum

eggs extruded in packets of 8-15 ova w/hexacanth hooks.

Front 38

Which hymenolepis spp is more important for disease in humans?

Back 38

H. nana: ingestion of ova leads to cysticercoid infestation of intestinal villi.

ingest cysticercoids --> mostly asymptomatic, no cysticercoids in villi

Front 39

Morphology of Hymenolepis nana adult?

Back 39

nana = "dwarf"

~2cm long, armed rostellum and 4 suckers

Front 40

Morphology of Hymenolepis diminuta adult?

Back 40

~10 inches long

unarmed rostellum

4 suckers

Front 41

Copepods are vectors for which infestations?

Back 41

-Diphyllobothrium latum
-Guinea Worm

Front 42

Prophylactic suggestions for Echinococcosis?

Back 42

educate people: don't feed your dogs sheep offal

antihelmitic dog enemas

Front 43

Suggestions for prevention of cysticercosis?

Back 43

wash your hands! you get it by fecal-oral autoinfection after regular T. solium infection.

no rimming without dental dams ;D