Lecture 1: Trematodes Flashcards
trematodes are
flukes
lizard poisoning fluke
platynosomum concinnum
where is the fluke found in the DH
Bile ducts of cats
Intermediate hosts of platynosomum concinnum (lizard fluke)
terrestrial snail (subulina, eulata) anolis lizards
paratenic host of platynosomum concinnum (lizard fluke)
pill bug
eggs of platynosomum concinnum (lizard fluke)
operculated eggs containing miracidium
what infects the snail (IH) in platynosomum life cycle
miracidium ingested by 1st IH the terrestrial snail
what leaves the terrestrial snail IH in platynosomum LC
miricidium hatches and sporocysts, cercariae burst out of snail
after the 1st IH (terrestrial snail) in platynosomum LC what happens next
cercariae can be ingested by pill bug or anole
anole can also eat infected pill bug
cercariae then encyst to metacercariae in bile ducts of anole lizard
platynosomum LC
Operculated eggs
miracidium in terrestrial snail
cercariae leave snail into 2IH
2IH has encysted metacercariae which is consumed by cat
dz seen with platynosomum in cats
typically asymptomatic
liver dz
cholangiocarcinoma
diagnosing platynosomum
fecal sedimentation - can be hard to pick up still
eosinophilia, increased ALT
visible on necropsy
treatment choice for platynosomum
praziquantel
no labeled treatments though!
the lung fluke
paragonimus kellicotti
lung fluke DH (paragonimus)
dogs, cats, mink, muskrat
lung fluke IH (paragonimus)
1st IH: aquatic snail (melania, ampullaria)
2nd IH: crayfish or crab
regional distribution of paragonimus (lung fluke)
eastern US
adult morphology differences of paragonimus vs. platynosomum
paragonimus is 2x larger and integument is covered in spines
adult paragonimus found in the __ of DH and passed in __
lungs (inside cysts), feces
paragonimus eggs require __ to hatch/complete LC
Water
miracidium will penetrate aquatic snail
what emerges from the aquatic snail in paragonimus LC
Cercariae
this penetrates the 2IH (crustation)
what happens to the cercariae of paragonimus in the crustation
encysts as metacercariae in heart, liver, muscles
what happens to the adult paragonimus in the lungs
they make a cyst, may be a pair in one
how do paragonimus flukes survive in the lung
cleave IgG to reduce eos and down regulate host inflamm response
clinical signs with paragonimus kellicottii (lung fluke)
juvi migration - peritonitis, hemorrhage
adults - chronic bronchitis, coughing, eos, pneumonia
is paragonimus kellicotti zoonotic?
yes! humans can get the lung fluke by ingesting undercooked crustations (crabs, cray fish)
what CS can be seen with paragonimus kellicotti infection in dogs, cats, and humans
normally asymptomatic
can have abdominal pain, diarrhea from fluke migration
can have pleural effusion, coughing, bronchopneumonia, chest pain from encysted flukes
what is a severe CS that can happen when paragonimus kellicotti infects humans
aberrant migration to the brain! (headache, vomiting, seizures, coma, death) usually seen in young adults 15-30yo
paragonimus kellicotti diagnosis
sedimentation
tracheal wash
rads
treatment for paragonimus kellicotti
none approved
same as with platynosomum; praziquantel, fenbendazole, albendazole (crosses BBB)
the salmon poisoning fluke
nanophyetus salmincola
region for nanophyetus salmincola infections
salmon poisoning fluke is mostly seen in pacific NW (travel hx is important)
DH for nanophyetus salmincola
dogs, cats, coyote, fox, fish-eating mammals (bears, humans)
IH for nanophyetus salmincola
1IH - aquatic snail (oxytrema) 2IH FISH (trout or salmon)
describe the eggs of flukes
operculated, usually darker colored and dense
describe eggs and adult nanophyetus salmincola
adults are very small, shaped kind of like a yeast/peanut
eggs are large, yellow-brown and operculated
LC of nanophyetus salmincola
miracidium penetrates aquatic snail
cercariae emerges from snail and penetrates fish
encysts as metacercariae in fish tissues
fish ingested by DH and fluke matures in SI
NO MIGRATION
CS of salmon poisoning
usually asymptomatic if only a nanophyetus salmincola infection
if co-infected with neorickettsia helminthoeca will see fever, anorexia, V/D, hemorrhagic enteritis, lymphadenopathy and death
treatment for salmon poisoning
praziquantel, fenbendazole for flukes
doxycycline for neorickettsia
diagnosis of nanophyetus salmincola
sedimentation
the canine blood fluke
heterobilharzia americana
describe the adult heterobilharzia mericana
look like nematodes, but they are flukes. NOT hermaphroditic like the other flukes discussed.
Where does the male carry the female heterobilharzia americana
in the gynecophoric canal
where is heterobilharzia located in DH
mesenteric and hepatic veins of dogs, bobcats, raccoons
where is heterobilharzia americana seen most often
gulf coast, louisiana bayous, mississippi delta
IH for heterobilharzia americana
aquatic snail (lymnaea)
how many IH are involved in LC for heterobilharzia
one, the aquatic snail
cercariae can cause skin irritation from penetration in which species of flukes
heterobilharzia americana zoonotic, causes “swimmer’s itch” aka cercarial dermatitis
treatment for most flukes
praziquantel, fenbendazole, albendazole
diagnosis for most flukes
fecal sedimentation
fluke which inhabits the SI of dogs and cats that has a unique route of trasmammary transmission
alaria spp.
IH for alaria spp.
1IH: aquatic snail (helisoma)
2IH: tadpole (rana pipiens)
paratenic hosts
describe the adult alaria flukes
spoon-shaped, have weird appendages at the anterior end that look like antenna
LC of alaria spp.
eggs pass in feces from DH
1IH miracidium penetrates aq snail and cercariae emerge
cercariae penetrate tadpole (2IH) and develop into mesocercaria and metacercariae - this can be ingested by paratenic host
infective stage of alaria to cat and dog
metacercariae
if a lactating cat ingests mesocercariae (juvi fluke) what happens
can migrate to mammary gland and infect kittens
alaria spp has __ migration
lung - can cause pulmonary hemorrhage
are there any approved drugs for treating flukes in SA?
No, usually use praziquantel, fenbendazole, and albendazole off label for treatment
flukes with zoonotic potential
paragonimus kellicotti (lung fluke); aberrant migration to brain heterobilharzia americana (canine blood fluke); swimmer's itch or cercarial dermatitis
phylum for flukes
Phylum; platyhelminthes “flatworms”
includes the trematodes “flukes” and cestodes “tapeworms”
flukes are in the class Trematoda
fluke morphological recap
dorsoventrally flattened
have a tegument (can be smooth or spined)
attachment organs; anterior feeding oral sucker and ventral attachment acetabulum
digestive ssytem has two blind ceca
excretory and nervous systems
hermaphroditic (with exception of schistosomes like heterobiharzia americana)
schistosomes “split bodied flukes” inhabit blood vessels of DH, they are NOT hermaphroditic and they look more like “roundworms”. Males have a gynecophoric canal to hold female in. We only discussed the canine blood fluke, heterobilharzia americana
typical lifecycle of fluke
operculated egg miracidium cercaria metacercaria - infective stage adult fluke
infective stage of fluke
metacercaria
