Parasitology - Lecture 8 Flashcards
What is a common name for Phylum Acanthocephala?
thorny headed worms
What are the general features of parasites of the phylum Acanthocephala?
body:
- thick cuticle
- made up of proboscis (retractable with hooks), neck and trunk (whitish, flattened with wrinkles)
- separate sexes (smaller males)
- no GIT
- indirect lifecycle
- parasite of the GIT in fish, birds and mammals
What 2 families are under the Phylum Acanthocephala?
Family Oligacanthorhynchidae
Family Polymorphydae
What 2 genuses belong to the family Oligacanthorhynchidae?
genus Macracanthorynchus
genus Oncicola
What genus belongs to the family Polymorphydae?
genus Polymorphus
What species and where does Macracanthorhynchus hirudinaceus infect?
small intestine of pigs
describe the morphology of Macracanthorhynchus hirudinaceus
- up to 35cm
- body is whitish or pale red,flattened, transversally wrinkled
- proboscis with 6 transverse rows of hooks
- eggs: 3 layers, embryonated
describe the lifecycle of Macracanthorynchus hirudinaceus
IH= may beetles, dung beetles, water beetles, etc.
- embryonated eggs pooped out
- beetles ingest eggs
- eggs develop infective stage (cystacanth)
- pigs ingest IH
PPT = 2-3 months
what are some features of Oncicola pomatostomi?
hosts: cats and dogs
location: small intestine
IH = unknown
DH infected by ingesting paratenic host (birds)
What species and where do Oncicola canis infect?
small intestine of cats and dogs
What species ad where do Polymorphus boschadis infect? what is the IH?
ducks, swans, fowl
small intestine
IH= fresh water shrimp
What is a common name for the phylum Platyhelminthes?
flatworms
describe the general features of parasites of the phylum platyhelminthes
- body dorsoventrally flattened, bilaterally symmetrical with no body cavity
- organs embedded in parenchyma
- body covered in syncytial tegument
- GIT: incomplete or absent
- circulatory and resp systems absent
- muscle layers developed
- organs of attachment to host: suckers and hooks
- usually hermaphrodites
What are 4 important classes within the phylum Platyhelminthes?
- Turbellaria
- Monogenea
- Trematoda
- Cestoda
describe the features of Turbellaria
- freshwater, marine or terrestrial
- almost entirely freeliving
describe the features of Monogenea
- ecto or endo parasites
- adhesive organs
- simple lifecycle, no alternation of hosts
describe the features of Trematoda
- flukes
- has suckers (oral and ventral)
- short and generally flat
- operculated eggs
- lifecycle involves at least 1 IH
- most are endoparasites, but some are ecto
describe the features of Cestoda
- tapeworms
- can be meters long
- body made of segments clled proglottids
- normally locate in small intestine
- lifecycle involves IH
describe the general features of the subclass Digenea (Trematodes)
- endoparasites
- attachment organ normally simple (unarmed ventral sucker)
- GIT well developed but incomplete (no anus). has mouth, oral sucker, pharynx, oesophagus, and caeca
- hermaphroditic usually
- M have testes
- F have ovaries, uterus, vitilline glands
- complex lifecycle normally with molluscan IH
What are the lifecycle stages of the subclass Digenea (Trematodes)
- adult
- operculated egg
- miracidium
- often ciliated, invade IH and multiply asexually - sporocyst
- a germinal sac - redia
- usually elongated with rudimentary GIT - cercaria
- forms inside IH and shed in environment. motile with tail - metacercaria
- encyst of cercaria
- mature to adult after ingestion - adult
describe the morphology of Fasciola hepatica
- leaf shaped
- anterior end ccone shaped, broad shoulders
- oral sucker at mouth and ventral sucker at shouders
- tegument has sharp spines
- caec branched and extend posteriorly
- testes are branched
- ovary located on to right of middle, anterior to testes
- uterus anterior to testes
- vitilline glands are on lateral sides
- eggs: thin shelled, yellow, operculated
What species and where does Fasciola hepatic infect? what is the IH?
adult worms in bile ducts of ruminants, pigs, hares, horses, dogs, humans, etc.
juvenile stages migrate through liver
IH = snails (Austropeplea tomentosa)
What conditions do Fasciola hepatica eggs need to develop?
- humidity
- good temp
- oxygen
describe the lifecycle of Fasciola hepatica
- eggs pooped out, miracidium begin to develop\
- must find IH within 24hrs. penetrate snail and become sporocysts and migrate to liver of snail where rediae developes
- rediae are motile and can cause damage to snail
- cercaria develop inside rediae
- 1 miracidium yields 4000 cercaria
- cercaria leave snail after 4-7 weeks and settle on objects like grass and encyst and turn into metacercaria
- DH ingests metacercaria which encyst in small intestine
- penetrate intestine and move to peritoneum and migrate to liver
- burrow through liver for 2 months causing extreme damage
- migrate to bile ducts and grow toadults
- PPT = 2 months
- feed on blood
