W5- Phylum Platyhelminthes (Class Trematoda)

Question 1

Phylum Platyhelminthes (Flat worm) characteristics

Answer 1

• dorso ventrally flattened-o2 diffuse
• triploblastic=ecto,meso,endoderm
• tissues into organs, head formed
• bilateral symmetry, no body cavity(acoelomate)
• mesosome (mesenchyme) =loose tissue surrounding int organs.
• 1 opening-digestive cavity for ingestion, another opening for egestion
• no specialised circulatory or respiratory organs

Question 2

Phylum Platyhelminthes nervous system?

Answer 2

ganglion type, 2 longitudinal nerve cords interconnected by transverse nerve.

Question 3

Phylum Platyhelminthes excretory system?

Answer 3

Protonephridia -flame cells remove waste material

Question 4

Phylum Platyhelminthes Reproductive system ?

Answer 4

most are hermaphrodites (both female and male repro organs)

Question 5

What is Class Trematoda?

characteristics?

Answer 5

• they are Flukes- parasitic worms.
• body=leaf shaped, flattened. - attach to def host using suckers (oral+ventral)
• hermaphrodites: 2 testes w/ sperm ducts that join, 1 ovarium

Question 6

what is Fasciola hepatica? what does it cause

Answer 6

common liver fluke,

causes fasciolosis

Question 7

Fasciola hepatica habitat

Answer 7

adults In liver+ binary passage of def host

Question 8

Fasciola hepatica morphology?

egg morphology?

Answer 8

size=30mm ‘big fluke’
body= leaf shape, brown/grey, covered by cuticle, ant cone-shaped part has 2 suckers (oral+ventral)
pair of vitelline glands to produce yolk

egg= oval, bile-stained, 140x80μm

Question 9

Fasciola hepatica transmission

Answer 9

ingestion of raw meat/ vegetation contaminated w/ i metacercariae

Question 10

Fasciola hepatica host

Answer 10

def host: cows, sheep
inter host: fresh water snails.

Question 11

Fasciola hepatica infective form

Answer 11

metacercaria

Question 12

Fasciola hepatica

1) excretory system?
2) nervous system?
3) reproductive system?
4) digestive system?

Answer 12

1) flame cells, protonephridial
2) ganglion type
3) hermaphrodies (M+F): 2 Testes, 1 ovary, branched uterus behind ventral sucker.
4) branched w/ 1opening, has mouth on oral sucker, pharnyx then oesphagus.

Question 13

Fasciola hepatica life cycle

Answer 13

1. unembry, eggs passes in feces, become embryonated in water
2. miracidia hatches. seek snail+penetrates it to reach liver
3. in snail liver: sporocyst—>rediae—>cercardiae
4. free free swimming cercardiae looses tail+ensts in aq.veg as metacercardiae
5. herbivore host ingests aq.veg w/ metacercardia= infected
6. they excyst in duodeum,SI+penetrate intestinal wall+go to liver of host and reside there

Question 14

how are Fasciola hepatica eggs released?

Answer 14

released w/ feces of infected host

Question 15

Phylum Platyhelminthes classes?

Answer 15

Trematoda= Flukes
Cestoda= Tapeworms

Question 16

what is Dicrocoelium dendriticum?

what does it cause

Answer 16

lancet liver fluke

causes dicrocoeliasis

Question 17

Dicrocoelium dendriticum host

Answer 17

Def host: lrg herbivores(mainly sheep)
2 inter host:
1) terrestrial snail
2) ants

Question 18

Dicrocoelium dendriticum transmission

Answer 18

ingestion of infected ants or ingesting food contaminated by infected ants

Question 19

Dicrocoelium dendriticum morphology

Answer 19

8-14 mm long. lancet shape.
2 suckers, transparent, internal organs visible.
ovary + testes irregular shape. uterus fills=posterior part
testes= anterior

Question 20

Dicrocoelium dendriticum infective form

Answer 20

metacercariae in infected ant

Question 21

Dicrocoelium dendriticum life cycle

Answer 21

1. embry. eggs containing metacercardia shed in faeces
2. eggs ingested by snail
3. miracidium hatch from egg in intestine+penetrates gut wall. Forms mother sporocyst. They produce 1st + 2nd gen daughter sporocyst with cercariae (asexual reproduction)
4. Cercariae released through snail slime ball
5. Ant eat cercariae in slime
6. Metacercaria encysts in ant. Cow ingest ant w/ metacercaria
7. Adult fluke resides in bile duct of liver

Question 22

Dicrocoelium dendriticum life cycle

Answer 22

1. embry. eggs containing metacercardia shed in faeces
2. eggs ingested by snail
3. miracidium hatch from egg in intestine+penetrates gut wall. Forms mother sporocyst. They produce 1st + 2nd gen daughter sporocyst with cercariae (asexual reproduction)
4. Cercariae released through snail slime ball
5. Ant eat cercariae in slime
6. Metacercaria encysts in ant. Cow ingest ant w/ metacercaria
7. Adult fluke resides in bile duct of liver

Question 23

what is Opisthorchis felineus?

what does it cause

Answer 23

its cat liver fluke

causes opisthorchiases

Question 24

what is Opisthorchis felineus?

what does it cause

Answer 24

its cat liver fluke

causes opisthorchiases

Question 25

Opisthorchis felineus habitat

Answer 25

in liver, pancreas, gall bladder

Question 26

Opisthorchis felineus transmission

Answer 26

ingesting undercooked fish containing metacercariae

Question 27

Opisthorchis felineus host

Answer 27

Def host: humans, dogs, cats (fish eating mammals)

2 inter hosts:

1) snail (brithynia)
2) freshwater fish

Question 28

Opisthorchis felineus morphology

Answer 28

size= 8-18mm
lancet shaped, 2 suckers, has excretory bladder (between 2 testes)

testes = posterior, uterus = fills anterior part.

Question 29

Opisthorchis felineus life cycle

Answer 29

1. embry. eggs passed in faeces
2. eggs ingested by snail. Eggs hatch into Miracidia—>sporocyst—>rediae—>cercariae
3. Free swimming cercariae released, penetrate and encyst in fish scale or muscles as metacercaria
4. cats/humans eat fish with metacercaria (infected)
5. they excyst in duodenum(SI). adult flukes reside in bilary duct

Question 30

Opisthorchis felineus infective form

Answer 30

metacercariae

Question 31

What is difference between Dicrocoelium dendriticum and Opisthorchis felineus?

Answer 31

In Dicrocoelium dendriticum testes= anterior

In Opisthorchis felineus testes= posterior

Question 32

what is Genus Schistoma?

what does it cause?

Answer 32

they are blood flukes

causes schistosomiasis

Question 33

Genus Schistoma morphology

Answer 33

• male= short (15mm) have a deep groove on ventral side where the female resides.
• female= longer and slender (25mm) they penetrate blood vessels
• 2 suckers

Question 34

Are Genus Schistoma flat worms?

Answer 34

Males= flat worms, 
female = cylindrical as they go into small vessels

Question 35

Genus Schistoma habitat

Answer 35

in abdominal veins of host

Question 36

Genus Schistoma types?

what do they cause?

Answer 36

• Schistosoma haematobium- causes Urinary schistosomiasis (Middle East, India, Africa)
• Schistosoma mansoni- causes Intestinal schistosomiasis (Middle East, S America, Africa)
• Schistosoma japonicum- causes acute Katayama
  fever (Japan, China)

Question 37

Genus Schistoma egg morphology

Answer 37

SH- egg pointed at posterior end (U)

SM- egg pointed lateral (F)

Question 38

Genus Schistoma Host

Answer 38

Def host: mammals, humans

inter host: snails

Question 39

Genus Schistoma infective form

Answer 39

Cercariae swim in water and penetrates through skin- has a bifurcated tail

NO METACERCARIAE

Question 40

Genus Schistoma transmission

Answer 40

contact of water contaminated w/ schistosoma eggs.

Question 41

Genus Schistoma life cycle

Answer 41

1. Eggs shed w/ feces (mansoni+japonium) or urine (heamatobium)
2. Eggs hatch + release miracidia which penetrate snail tissue
3. Snail produces 2 gen of sporocyst +cercariae. released into water
4. cercariae penetrate skin using forked tail, then lose tail—>schistosomulae which bloodstream to get to heart and lungs then mature in liver
5. Adult worms reside in blood vessels in intestine where they release eggs.(mansoni+ japonium=intestines, heamatobium=bladder)