flukes Flashcards
all trematodes are hermaphrodties except for what species of fluke?
blood flukes
basic life cycle of trematodes (flukes) of domestic animals
eggs release in feces –> miracidia get released from eggs and miracidia enter intermediate host –> asexual repro happens in intermediate host and produce cercariae –> can either develop into infective stage metacercaeriae or encyst as meracercaeiae 2nd intermediate host –>metacercariae inside definitive and develop into adult fluke
how are fluke eggs released in the host?
feces
what stage in the flukes lifecycle infect enters a snail as a intermediate host?
miracidia
fluke eggs develop and hatch in? to release what?
water
-to release miracidia
what occurs in the intermediate host of the fluke?
asexual reproduction producing large amounts of cercariae
what stage of the fluke lifecycle exists the snail and enters the definitive host?
cercariae
what is the infective fluke stage?
metacercariae
after cercaeriae exits the snail what are the three possible ways it can infect the definitive host?
-develops into metacercariae encysts on vegetation and gets eaten by definitive host
-encysts as metacercariae in tissues of a 2nd intermediate host and then eaten by definitive host
-actively penetrates the skin of definitive host
name of common liver fluke
fasciola hepatica
what is the intermediate host of fasciola hepatica?
lymnaeid snails
what species of adult fluke colonize bile ducts of mammals?
fasciola hepatica
what is transmitted by ingestion of metacercariae on vegetation, adults colonize bile duct of animals
fasciola hepatica
what is caused by invasion of liver by young flukes from recent ingested metacercariae
acute fascioliasis
what animal is most prone to die from acute fascioliasis?
sheep
what is the disease associated with the presence of adult flukes in the bile ducts?
chronic fascioliasis caused by prolong period of ingestion of fasciola hepatica at moderate amounts
Dx of fasciola hepatica
fecal ova and parasite prep
ELISA
what causes bottle jaw in sheep?
fasciola hepatica
what is the north american lung fluke
paragonimus kellicotti
what species causes infection by eating crayfish containing encysted metacercariae or by eating animals that have recently fed on crayfish?
paragonimus kellicotti
what species of adult fluke infects lungs of cats, dogs, and many wild animals?
paragonimus kellicotti
what is the preferred 1st intermediate host of paragonimus kellicotti?
slender walker snail
what is the preferred 2nd intermediate host of paragonimus kellicotti?
crayfish
**infection only happens by this
what species often occur in pairs in pulmonary cysts
paragonimus kellicotti
operculate egg which is released into the respiratory tract and is passed into the environment
paragonimus kellicotti
lifecycle of paragonimus kellicotti
operculate egg release into resp tract and passed into environment –> miracidium released from egg into fresh water –> miracidium infects snail –> after asexual repro in snail cercariae are released –> cercaeriae infect crustacean host and encyst as metacercariae –> ingestion of crustacean infects definitive host
ciliated miracidium is released from each egg in freshwater
paragonimus kellicotti
what young flukes excyst from ingested metacercaria, migrate through gut wall and diaphragm, pair up and mature within lung parenchyma, become encapsulated by granulation tissue and collagen
paragonimiasis caused by paragonimus kellicotti
causes pleuritis, pleural effusion, pneumothorax, bronchiectasis, pneumonia, pulmonary hemorrhage
paragonimus kellicotti
Dx paragonimiasis
ID unembryonated operculate eggs
Lung Xrays
what species of fluke causes the disease known as dicrocoeliosis
dicrocoelium dendriticum
adults that live in the gallbaldder, bile and pancreatic ducts of mammals (primarily domestic ruminants)
dicrocoelium dendriticum
causes infection occurs by eating ants containing encysted metacercariae
dicrocoelium dendriticum
what is the ideal habitat for both intermediate hosts of dicrocoelium dendriticum?
dry lowland or mountain pastures
what is the 1st intermediate host of dicrocoelium dendriticum
terrestrial snails
what is the 2nd intermediate host of dicrocoelium dendriticum
ants
infection occurs by eating ants containing encysted metacercariae
dicrocoelium dendriticum
what is the main economic impact of dicrocoeliosis
due to rejection of infected livers from slaughtered animals
what causes no clinical illness in cattle, lambs, or yearling sheep?
dicrocoelium dendriticium
in older sheep, infection causes progressive hepatic cirrhosis, lowered wool production, decreased lactation
dicrocoelium dendriticium
Dx of dicrocoeliosis
ID of eggs in feces
ELISA
no metacercarial stage, the cercariae penetrate skin of host
schistosomatidae
sexes are separate in what species?
schistosomatidae
adults primarily infect veins of mesenteries of the digestive & urinary tract of mammals and birds
schistosomatidae
North American schistosome
heterobilharzia americana
most clinical cases in dogs (canine schistosomiasis)
heterobilharzia americana
intermediate host of heterobilharzia Americana
lymnaeid snails
infection occurs when dogs come in contact with freshwater lakes or streams contaminated with infective cercariae
heterobilharzia americana
cercariae penetrate skin, young flukes migrate to liver, mature, then move to mesenteric veins
heterobilharzia americana
many eggs become lodged in intestinal wall, liver, and other visceral organs
heterobilharziasis
heterobilharizia americana
Dx heterobilharziasis
ID of eggs in feces or biopsy samples
ELISA & PCR
