Trematodes Flashcards
Describe the characteristics of trematodes.
-dorso-centrally flattened
-oral & ventral suckers
-incomplete alimentary tract (no anus)
-hermaphroditic
-indirect = aquatic snails (IH)
-site of infection in FH (depends on species)
>bile duct, alimentary tract, vascular system
-pathogenesis
>depends on organs & adult/immature fluke
-diagnosis
>fecal sediment (eggs are lg & heavy)
Definitions!
-miracidia = free living ciliated larva
-cercariae = tadpole like larvae, final & free swimming
-metacerceriae = encysted resting stage infective stage
Life cycle of trematodes (1 IH VS 2 IH).
SUMMARY
1. Eggs passes in FHs feces, urine, sputum
2. Miracidium develops in egg & released in water
3. Snail development
>miracidium enters snail
>develops into sporocyst
>develops redia (daughter sporocysts)
>cercaria leave snail
4. Cercaria encyst on plant/animal 2nd IH = metacerceriae
5. Metacercariae ingested by FH = adult flukes
Describe Fasciola hepatica general characteristics.
‘Liver fluke’
-FH: cattle, sheep, goat, other ruminants
-IH: snails
-accidental hosts: horse & humans zoonotic
>raw veggies/plants contaminated w encysted metacercariae
Describe Fasciola hepatica clinical signs.
-site of infection = bile ducts (liver)
>mature flukes in gall bladder
-immature fluke migrate in liver & feed = fibrosis replace necrotic tracts
>lg amount of immature fluke in liver -> acute form of disease
-adults consume blood, irritate host liver tissue, chronic bile duct inflammation ‘pipe-stem liver’
-anemia, diarrhea, inappetence, bottle jaw, decreased production of milk, weight loss, affects repro
-increased susceptibility to other diseases (ex. Clostridia black disease, salmonellosis)
Describe Fasciola hepatica diagnosis & treatment/prevention.
DIAGNOSIS
-fecal sediment
-bulk milk ELISA
-flukes in liver at necropsy = economic loss
-high globulin, high alb, high GGT
TREATMENT/PREVENTION
-flukicides
>triclabendazole against adults & immature flukes
-snail control & management (drain/fence wet pasture) = challenging!
-determine local parasite transmission patterns
-reduce pasture infectivity by killing adult flukes
Describe Fascioloides magna general characteristics.
‘Deer fluke, lg American liver fluke’
-FH: white tailed deer, elk, caribou, wild cervids
-IH: fresh water snails
-aberrant hosts: sheep, goats
-DEH: cattle, horse, pig
-adults 30cm (huge)
-PPP: 8 mo
Describe Fascioloides magna life cycle in DH, DEH, & aberrant host.
-similar to F. Hepatica
-DH:
>immature flukes travel through liver parenchyma
>forms fibrous cyst around adults in pairs in liver
>eggs made & made thru hole in cyst to enter bile & pass out w feces
-DEH:
>cyst encapsulates fluke in liver, non patent so no cyst hole = no eggs
-aberrant host:
-immature flukes travel thru liver, no cyst, animal dies before PPP = no cyst, adults, eggs
Describe Fascioloides magna clinical signs, diagnosis, & treatment/prevention.
CLINICAL SIGNS
-deer & cattle = parasite encapsulated by host minimizes CS
-economic loss from condemned cattle liver
-sheep & goats = continued migration of immature flukes in liver -> death before PPP
DIAGNOSIS
-DH: fecal sediment
-necropsy of DEH & aberrant host (eggs not present)
TREATMENT/PREVENTION
-flukicides against migrating immature flukes
-snail control (challenging)
-drain/fence off wet pasture (challenging)
-dont farm deer & livestock together
Describe Paramphistomum spp. general characteristics.
‘Rumen fluke’
-DH: cattle, sheep, goat, deer, buffalo, antelope
>alimentary tract
-IH: fresh water snail
-adults = pear shape, red
>in rumen
-immature stage in duodenum for 6 wks
-egg = clear vs yellow
-PPP: 7-10wk
-life cycle similar to F. Hepatica
Describe Paramphistomum spp clinical signs, diagnosis, treatment/prevention.
CLINICAL SIGNS
-non path
-lg # migrating immature in young animals = enteritis, diarrhea, anorexia, depression, dehydration, anemia, hemorrhage, bottle jaw
DIAGNOSIS
-acute disease during PPP
-CS in young animals
TREATMENT/PREVENTION
-oxyclozanide (mature/immature)
-niclosamide (immature)
-drain/fence off wet pasture (challenging)
Describe Dicrocoelium spp general characteristics.
‘Lanceolate fluke’
-FH: sheep, goat, deer, carnivore
zoonotic
-IH: 1) land snail 2) brown ant
-adults = pear shape, red
>in bile duct
CLINICAL SIGNS
-adults non path
-heavy infection = fibrosis of bile ducts, cholecystitis, liver abscess, cirrhosis
DIAGNOSIS & TREATMENT
-fecal sediment
-praziquantel, niclosamide
-rule out infection in human from ingesting infected animal liver
Trematodes in lg animals summary!
Describe Paragonimus kellicotti.
‘Lung fluke’
-FH: dog, cat carnivores
-IH: 1) snails 2) crayfish
ID
-adults: ovoid, red/brown w spiny tegument
-egg: oval, yellow/brown, distinct operculum
SITE
-lung parenchyma
CLINICAL SIGNS
-developing flukes cause cyst formation
-intermittent cough
-heavy infections = severe cough, dyspnea, pneumothorax, bronchiectasis, hemoptysis, pneumonia & death
DIAGNOSIS
-fecal sediment
-transtracheal wash = eggs
-X-rays = show cysts
TREATMENT
-praziquantel
Describe Nanophyetus salmincola.
‘Salmon poisoning fluke’
-NW pacific USA & CA
-FH: dogs, cats, humans zoonotic
-IH: 1) snails 2) salmonid fish
ID
-adult: ovoid, white
-egg: oval, yellow/brown, thick shell
SITE
-adult in sm intestine
CLINICAL SIGNS
-pathogenic in dogs
-vector of neorickettsia helminthoeca = salmon poisoning -> severe hemorrhagic enteritis in dogs
*salmon poisoning = fever, hemorrhagic enteritis, enlarged LN, vomiting, diarrhea, weight loss, high mortality
DIAGNOSIS
-fecal sediment
TREATMENT
-praziquantel or fenbendazole
-tetracycline for rickettsial infection
Describe Alaria spp.
‘Intestinal fluke’
-FH: dog, cat
-IH: 1) snails 2) tadpoles
-PH: frog, snake, mice, bird, boar, humans zoonotic
ID
-adult: pink or brown
-egg: oval, honey, distinct operculum, 130um
SITE
-adults in sm intestine
-immature stage in lungs
CLINICAL SIGNS
-adults = no CS
-migrating mesocercariae cause pulmonary hemorrhage
DIAGNOSIS
-fecal sediment
TREATMENT
-praziquantel
Describe Platynosomum fastosum.
‘Liver fluke of cats’
-FH: cats
-IH: 1) snails 2) crustacean
-PH: lizards, toads
ID
-egg: oval, brownish, thick shell, in distinct operculum
SITE
-bile ducts
CLINICAL SIGNS
-hyperplastic bile ducts
-lizard poisoning
-palpable liver (hepatomegaly), icterus (jaundice), death
DIAGNOSIS
-eggs via double centrifuge w sugar
-liver biopsy
-ultrasound
TREATMENT
-praziquantel
*PPP: 3 mo
