Introduction to Helminths Flashcards
what are the three phylums of helminths?
nematoda
platyhelminthes
acanthocephala
what types of worms belong to the platyhelminth phylum?
tapeworms
flukes
what are paratenic hosts?
transport host: no changes within
true/false: in helminths with indirect life cycles, they require an intermediate host
true
what is the prepatent period?
from when the patient becomes infected to when that infection can be detected diagnostically
what is the body shape of nematoda?
long, cylindrical, unsegemented
what phylum(s) are pseudocoelomate?
nematoda
acanthocephala
are trematoda segmented?
no
what is the body shape of trematoda and what phylum are they a part of?
dorsoventrally flat, unsegmented
platyhelminthes
what is the digestive tract like in acanthocephala?
absent
what are two species that are oviparous?
roundworms like toxocara (ascarid)
hookworms like ancylostoma spp
what is usually the infective stage in nematodes with the direct life cycle?
L3
how can hosts become infected with nematodes that have the direct life cycle?
ingestion
skin penetration
transmammary
transplacental
(ingestion of parasitic host)
how can hosts become infected with nematodes that have the indirect life cycle?
ingestion of intermediate host
transmission via bloodmeal from intermediate host
(ingestion of paratenic host)
what are some nematode strategies for survival?
hypobiosis
periparturient rise
autoinfection
true/false: adult cestodes are usually not pathogenic
true
what metacestodes develop into one adult in the definitive host?
cysticercus
strobilocercus
cysticercoid
what metacestodes develop into multiple adults in the definitive host?
coenurus
unilocular hydatid cyst
alveolar hydatid
what are diphyllobothriideans?
have 2 metacestode stages
aquatic system required
what are the two stages of diphyllobothriideans?
procercoid develops in first intermediate host- usually copepod IH
plerocercoid develops in second intermediate host
what type of life cycle do cestodes have?
indirect
where are the genital pores located in cyclophyllidea and diphyllobothriidea?
cyclophyllidea: lateral
diphyllobothriidea: medial
what is special about trematode eggs?
operculated
what type of life cycle do trematodes have?
indirect