6, 34 Helminth 1

Exam 2,

what is the kingdom for helminths

Animalia

What are the 3 phylum of helminths

Platyhelminthes, nematoda, and acathocephala

What are the 2 classes under platyhelminthes

Trematoda and Cestoda

what is the main feature of nematodes

mouth and anus

what is the distinguishing feature of trematodes

have a mouth in which food is ingested and waste is expelled

what is the distinguishing feature of cestodes

no gut and absorb nutrients through cuticle

What is the host parasite relationship

co-evolved

rarely cause death

infections may be debilitating

what can helminths do to the host immune system

modulate it to thier advantage, very hard to create vaccines

what are the 3 ways helminths invade the host

ingestion of an infected stage

direct penetration through skin

penetration through skin wound by an insect vector

How many larval stages do nematodes have before adult

5

what larval stage of nematodes is infectious

L3

What is the infective stage of trematodes

metacercaria

what is the infectious stage of a primatiove cestode

plerocercoid

what is the infectious stage of true cestodes

metacestode

what is the definitive host

where the parasite matures and reproduces

what is the intermediate host

where immature stages develop in indirect life stages, essential for life cycle

what is a transport host

Takes up immature form but does not retain it. Not essential

What is an accidental host

Immature stage is retained in host tissue but no development. Not essential

How do nematodes reproduce

Sexual reproduction

ployandrous

how do trematodes reporduce

hermaphroditic

how do cestodes reproduce

each proglottid has complete set of both male and female

outcrossing and self fertilization

what is the structure of nematodes

covered in tough chitinous cuticle

what is the term for the internal structure of nematodes

pseudocoelomates

WHat is the internal structure of nematodes

Body cavity of fluid under pressure, internal organs suspended in fluid

How do nematodes move

Body wall muscles, thrash from side to side

What coordinates nematodes movement

nervous system

What do nematodes lack

distinct circulatory and respiratory system

How does circulation happen in nematodes

when fluids slosh back and forth

How does respiration happen in nematodes

diffusion of gases across cuticle

What behavior do some nematodes have

migratory through the host before reaching final location

What is the pre-patent period

while in definitive host- time from infection to reproductive adults

what does the pre patent period determine

the treatment intervals that suppress fecal egg output

what is psyiological hypobiosis in nematodes

Larvae enter hyperbiotic state in tissues, reactivated 3 weeks before birth to go infect fetus

what is seasonal hypobiosis

larvae invested in fall, chill in the gastric glands, larvae resume in spring

How many hosts do trematodes require

at least 2

What is the general structure of trematodes

Flat, bilaterla symmetry

2 suckers

incomplete digestive system

what trematode doesnt use hermaphroditism

schistosomes

What is the first intermeidate host of a trematode

Mollusk, usually a snail

What host do trematodes penetrate

Their intermediate host only, not the definitive

How do trematodes infect their definitive host

Through unembroyonated eggs being passed in feces

where can trematodes live

On land or in the water

how does cercariae become metacercaria

Shed its tail which becomes protective outer layer

What is the trematode life cycle

Miracidium to sporocyst to redid to cercariae

where are the trematode snails found

Ponds and slightly acidic marshy areas

Where are cestodes found in the definitive host

Intestine

what life cycle do cestodes have

indirect life cycle

what parts make up the body of a cestode

scolex, neck, strobila

what is the scolex of a cestode

the anchor

what is the strobila of a cestode

body

where are eggs found in cestodes

at end of tail

where are the hooks found on a cestode

on the scolex

what is the main physical feature on a true cestode

suckers and hooks

what is the main physical feature on a primitive cestode

bothria (slits/groves)

what do true cestodes contain

oncosphere diverse larval types

how many hosts do true cestodes have

2, 1 intermediate and 1 definitive

how many hosts do primitive cestodes have

at least 2 intermediate hosts

what are the eggs of primitive cestodes decribed as

operculate eggs

what do the eggs of true cestodes look like

sunny side up egg

what do the eggs of primitive cestodes look like

granulated egg

what is the survival strategy of cestode reproduction

produce large quantities of eggs with low survival rates

how are true cestode eggs shed

in feces

what happenes when true cestode eggs are shed

they develope an onchophere

what happens to the true cestode when the intermediate host ingests the onchophere

it develops hexacanth (hooks)

what happens after a true cestode onchophere is ingested

it migrates to its predilection site and develops into the metacestode

what are the larval stages of a metacestode

cysticercus

strobilocercus

coenurus

unilocular hydatid cyst

cysticercoid

what is a cyclophyllidea

larval stage of true metacestode

bladder worm

simplest type

1 protoscolex, invaginated scolex

becomes singular adult

what is a strobilocercis

larval stage of true metacestode

more developed that cysti

some strobilization

1 protoscolex

what is a coenurus

larval stage of true metacestode

multiple protoscolices

single, fluid filled bladder

what is a unilocular hydatid cyst

larval stage of true metacestode

thick walled, fluid filled bladder

progressively slow growing

multiple protoscolices

endogenous budding

what is a multilocular hydatid cyst

larval stage of true metacestode

exogenous budding

alveolar appearance

aggressively fast growing

multiple protocolices

grows like cancer

what is a cysticercoid

larval stage of true metacestode

fully developed, invaginated protoscolex

single protoscolex

dense, solid, not fluid billed

found in arthropod intermediate hosts

what is a plerocercoid

primitive cestode larval stage

found in 2nd intermediate host

no hooks

some strobilization