W5- Phylum Platyhelminthes (Class Trematoda) Flashcards
Phylum Platyhelminthes (Flat worm) characteristics
- 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
Phylum Platyhelminthes nervous system?
ganglion type, 2 longitudinal nerve cords interconnected by transverse nerve.
Phylum Platyhelminthes excretory system?
Protonephridia -flame cells remove waste material
Phylum Platyhelminthes Reproductive system ?
most are hermaphrodites (both female and male repro organs)
What is Class Trematoda?
characteristics?
- 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
what is Fasciola hepatica? what does it cause
common liver fluke,
causes fasciolosis
Fasciola hepatica habitat
adults In liver+ binary passage of def host
Fasciola hepatica morphology?
egg morphology?
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
Fasciola hepatica transmission
ingestion of raw meat/ vegetation contaminated w/ i metacercariae
Fasciola hepatica host
def host: cows, sheep inter host: fresh water snails.
Fasciola hepatica infective form
metacercaria
Fasciola hepatica
1) excretory system?
2) nervous system?
3) reproductive system?
4) digestive system?
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.
Fasciola hepatica life cycle
- unembry, eggs passes in feces, become embryonated in water
- miracidia hatches. seek snail+penetrates it to reach liver
- in snail liver: sporocyst—>rediae—>cercardiae
- free free swimming cercardiae looses tail+ensts in aq.veg as metacercardiae
- herbivore host ingests aq.veg w/ metacercardia= infected
- they excyst in duodeum,SI+penetrate intestinal wall+go to liver of host and reside there
how are Fasciola hepatica eggs released?
released w/ feces of infected host
Phylum Platyhelminthes classes?
Trematoda= Flukes Cestoda= Tapeworms
what is Dicrocoelium dendriticum?
what does it cause
lancet liver fluke
causes dicrocoeliasis
Dicrocoelium dendriticum host
Def host: lrg herbivores(mainly sheep)
2 inter host:
1) terrestrial snail
2) ants
Dicrocoelium dendriticum transmission
ingestion of infected ants or ingesting food contaminated by infected ants
Dicrocoelium dendriticum morphology
8-14 mm long. lancet shape.
2 suckers, transparent, internal organs visible.
ovary + testes irregular shape. uterus fills=posterior part
testes= anterior
Dicrocoelium dendriticum infective form
metacercariae in infected ant
Dicrocoelium dendriticum life cycle
- embry. eggs containing metacercardia shed in faeces
- eggs ingested by snail
- miracidium hatch from egg in intestine+penetrates gut wall. Forms mother sporocyst. They produce 1st + 2nd gen daughter sporocyst with cercariae (asexual reproduction)
- Cercariae released through snail slime ball
- Ant eat cercariae in slime
- Metacercaria encysts in ant. Cow ingest ant w/ metacercaria
- Adult fluke resides in bile duct of liver
Dicrocoelium dendriticum life cycle
- embry. eggs containing metacercardia shed in faeces
- eggs ingested by snail
- miracidium hatch from egg in intestine+penetrates gut wall. Forms mother sporocyst. They produce 1st + 2nd gen daughter sporocyst with cercariae (asexual reproduction)
- Cercariae released through snail slime ball
- Ant eat cercariae in slime
- Metacercaria encysts in ant. Cow ingest ant w/ metacercaria
- Adult fluke resides in bile duct of liver
what is Opisthorchis felineus?
what does it cause
its cat liver fluke
causes opisthorchiases
what is Opisthorchis felineus?
what does it cause
its cat liver fluke
causes opisthorchiases
Opisthorchis felineus habitat
in liver, pancreas, gall bladder
Opisthorchis felineus transmission
ingesting undercooked fish containing metacercariae
Opisthorchis felineus host
Def host: humans, dogs, cats (fish eating mammals)
2 inter hosts:
1) snail (brithynia)
2) freshwater fish
Opisthorchis felineus morphology
size= 8-18mm
lancet shaped, 2 suckers, has excretory bladder (between 2 testes)
testes = posterior, uterus = fills anterior part.
Opisthorchis felineus life cycle
- embry. eggs passed in faeces
- eggs ingested by snail. Eggs hatch into Miracidia—>sporocyst—>rediae—>cercariae
- Free swimming cercariae released, penetrate and encyst in fish scale or muscles as metacercaria
- cats/humans eat fish with metacercaria (infected)
- they excyst in duodenum(SI). adult flukes reside in bilary duct
Opisthorchis felineus infective form
metacercariae
What is difference between Dicrocoelium dendriticum and Opisthorchis felineus?
In Dicrocoelium dendriticum testes= anterior
In Opisthorchis felineus testes= posterior
what is Genus Schistoma?
what does it cause?
they are blood flukes
causes schistosomiasis
Genus Schistoma morphology
- 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
Are Genus Schistoma flat worms?
Males= flat worms, female = cylindrical as they go into small vessels
Genus Schistoma habitat
in abdominal veins of host
Genus Schistoma types?
what do they cause?
- 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)
Genus Schistoma egg morphology
SH- egg pointed at posterior end (U)
SM- egg pointed lateral (F)
Genus Schistoma Host
Def host: mammals, humans
inter host: snails
Genus Schistoma infective form
Cercariae swim in water and penetrates through skin- has a bifurcated tail
NO METACERCARIAE
Genus Schistoma transmission
contact of water contaminated w/ schistosoma eggs.
Genus Schistoma life cycle
- Eggs shed w/ feces (mansoni+japonium) or urine (heamatobium)
- Eggs hatch + release miracidia which penetrate snail tissue
- Snail produces 2 gen of sporocyst +cercariae. released into water
- cercariae penetrate skin using forked tail, then lose tail—>schistosomulae which bloodstream to get to heart and lungs then mature in liver
- Adult worms reside in blood vessels in intestine where they release eggs.(mansoni+ japonium=intestines, heamatobium=bladder)
