Introduction to Helminths

Question 1

what are the three phylums of helminths?

Answer 1

nematoda
platyhelminthes
acanthocephala

Question 2

what types of worms belong to the platyhelminth phylum?

Answer 2

tapeworms
flukes

Question 3

what are paratenic hosts?

Answer 3

transport host: no changes within

Question 4

true/false: in helminths with indirect life cycles, they require an intermediate host

Answer 4

true

Question 5

what is the prepatent period?

Answer 5

from when the patient becomes infected to when that infection can be detected diagnostically

Question 6

what is the body shape of nematoda?

Answer 6

long, cylindrical, unsegemented

Question 7

what phylum(s) are pseudocoelomate?

Answer 7

nematoda
acanthocephala

Question 8

are trematoda segmented?

Answer 8

no

Question 9

what is the body shape of trematoda and what phylum are they a part of?

Answer 9

dorsoventrally flat, unsegmented
platyhelminthes

Question 10

what is the digestive tract like in acanthocephala?

Answer 10

absent

Question 11

what are two species that are oviparous?

Answer 11

roundworms like toxocara (ascarid)
hookworms like ancylostoma spp

Question 12

what is usually the infective stage in nematodes with the direct life cycle?

Answer 12

L3

Question 13

how can hosts become infected with nematodes that have the direct life cycle?

Answer 13

ingestion
skin penetration
transmammary
transplacental
(ingestion of parasitic host)

Question 14

how can hosts become infected with nematodes that have the indirect life cycle?

Answer 14

ingestion of intermediate host
transmission via bloodmeal from intermediate host
(ingestion of paratenic host)

Question 15

what are some nematode strategies for survival?

Answer 15

hypobiosis
periparturient rise
autoinfection

Question 16

true/false: adult cestodes are usually not pathogenic

Answer 16

true

Question 17

what metacestodes develop into one adult in the definitive host?

Answer 17

cysticercus
strobilocercus
cysticercoid

Question 18

what metacestodes develop into multiple adults in the definitive host?

Answer 18

coenurus
unilocular hydatid cyst
alveolar hydatid

Question 19

what are diphyllobothriideans?

Answer 19

have 2 metacestode stages
aquatic system required

Question 20

what are the two stages of diphyllobothriideans?

Answer 20

procercoid develops in first intermediate host- usually copepod IH
plerocercoid develops in second intermediate host

Question 21

what type of life cycle do cestodes have?

Answer 21

indirect

Question 22

where are the genital pores located in cyclophyllidea and diphyllobothriidea?

Answer 22

cyclophyllidea: lateral
diphyllobothriidea: medial

Question 23

what is special about trematode eggs?

Answer 23

operculated

Question 24

what type of life cycle do trematodes have?

Answer 24

indirect

Question 25

what type of life cycle do acanthocephalans have?

Answer 25

indirect