14 - helminths

Question 1

3 main groups of helminths infecting humans

Answer 1

cestodes - tapeworms
nematodes - roundworms
trematodes - flukes/flatworms

Question 2

definitive host

Answer 2

host in which sexual cycle takes place

Question 3

intermediate host

Answer 3

host win which larvae develop

Question 4

cestodes

Answer 4

taenia sodium - pork tapeworm
taenia siginata - beef tapeworm
echinococcus granulises - dog tapeworm

Question 5

taenia solium

Answer 5

cestode
pork tapeworm
cause of cysticercosis

Question 6

taenia saginata

Answer 6

cestode

beef tapeworm

Question 7

Echinococcus granulosus

Answer 7

cestode
dog tapeworm
cause of hydatid disease

Question 8

cause of cysticercosis

Answer 8

taenia solium

Question 9

dog tapeworm

Answer 9

Echinococcus granulosus

Question 10

cause of hydatid disease

Answer 10

echinococcus granulosus

Question 11

beef tapeworm

Answer 11

taenia saginata

Question 12

cestodes reservoirs of infection

Answer 12

mammals eg. pigs, cattle, dogs

Question 13

humans infected with cestodes by

Answer 13

cosumption of cysts in raw/undercooked meat (t. saginata or T solium) or ingestion of ova/proglottid segments (E. granulosus, T solium)

Question 14

adult cestodes live in

Answer 14

the intestine

they shed ova/proglottids into faeces

Question 15

cysts

Answer 15

contain larvae and m ay form in tissues (T. solum, E. granulosus)

Question 16

nematodes

Answer 16

ascaris lumbricoides 
enterobius vermicularis 
trichuris trichiura 
stronglyoides stercoralis 
necator, ancyclostoma
onchocerca, Loa-Loa
wuchereria, Brugia

Question 17

ascaris, enterobius and trichuris transmission

Answer 17

faecal-oral transmission - ingestion of ova

adult worms develop in the intestine and shed ova

Question 18

stronglyoides transmission

Answer 18

larvae penetrate intact skin

adults develop in intestine, ova shed in faeces

Question 19

hookworm transmission

Answer 19

larvae penetrate intact skin
adults develop in intestine of humans, dogs, cats.
ova shed in faeces

Question 20

filarial nematodes

Answer 20

microfilariae (larval forms) transmitted via blood-sucking fly and mosquito vectors
adults develop in tissues and lymphatics

Question 21

trematodes

Answer 21

schistosome
facciola hepatica
colonorchis sinensis
paragonimus westermani

Question 22

fascoila hepatica

Answer 22

common liver fluke

Question 23

clonorchis sinensis

Answer 23

Chinese liver fluke

Question 24

paragonimus westermani

Answer 24

lung fluke

Question 25

schistosoma transmission

Answer 25

trematode
larvae penetrate intact skin
adult worms develop in venous plexuses of bladder or bowel
ova shed in urine or faeces into water
eggs hatch in water, larvae penetrate freshwater snails (intermediate host)

Question 26

intermediate host of schistosoma

Answer 26

freshwater snails

Question 27

liver/lung flukes tranmission

Answer 27

ingestion of cysts in water plants (fasciola), freshwater fish (clonorchis) or crabs/crayfish (paragonimus)
fish or crustaceans and water-snails act as intermediate hosts.
adults worms live in bile ducts (liver flukes) or lungs (paragonimus). ova shed faeces into water

Question 28

3 main groups of helminths are distinguished by

Answer 28

distinctive lifecycles and morphology