Trematodes, Acanthocephalans, Annelids, and Helminths of Exotic species

Trematodes - Monogenean

• ectoparasite of fish & other aquatic animals

• have prominent attachments called haptor

• direct life cycle

• farmed and wild fish

Trematodes - Digenean

• endoparasites of humans, domestic, and wild animals

• have a complex indirect life cycle

• use mollusk intermediate hosts

• dorsoventrally flattened

• leaf shaped

• unsegmented

Digenean Trematode - General Life Cycle

• life cycle :

• definitive host :

• intermediate host:

• infective stage for definitive host:

• indirect

• grazing mammal or other vertebrate

• 1st intermediate host mollusk

  • 2nd intermediate host varies

• metacercaria

Digenean Trematode - General life cycle

• eggs

• larval stages

  • miracidium

  • sporocyst

  • redia

  • cercaria

  • metacercaria

• adult fluke

Fasciola hepatica

liver fluke

Fasciola hepatica

• definitive host :

• intermediate host:

• infective stage for definitive host:

• ruminants, rabbits, sometimes horses

• 1st intermediate host : mud snail

  • 2nd intermediate host : vegetation

• metacercaria on vegetation

Fasciola hepatica

• adults live in ________

• most economically important _____

• bile ducts

• fluke

Fasciola hepatica

• 1st intermediate host

• _______

• seasonal ______

• wet conditions → ______ → ______

• dry conditions → _______ → ______

• mud snail

• occurrence

• increased temporary habitats → increased risk disease

• permanent habitats only → decreased risk of disease

Fasciola hepatica

• ______ over short time → _____ disease

• ______ over long time → _____ disease

• large numbers ….. acute

• smaller numbers ….. chronic

Zoonotic

Paramphistomum & Cotylophoron

Ruman flukes (and reticulum flukes)

Paramphitomum and Cotylophoron

• definitive host :

• intermediate host:

• infective stage for definitive host:

• ruminants

• 1st intermediate host water snail

  • 2nd intermediate host vegetation

• metacercaria on vegetation

Paramphistomum & Cotylophoron

• juveniles are ______

  • disease when a lot of ________

  • diarrhea when immature flukes migrating to ____

• pathogenic

  • metacercaria eaten

  • rumen

Dicrocoelium dendriticum

lancent fluke

Lancent fluke

• definitive host :

• intermediate host:

• infective stage for definitive host:

• ruminants

• 1st intermediate host : land snail

  • ingestion fluke eggs from feces

  • excreted by snail in “slime balls”

• 2nd intermediate host : wood ant

  • behavior altered

  • climb on tops of grass

• metaceraria in ant

Nanophyetus salmincola

salmon poisoning fluke of dogs

Nanophyetus salmincola

• definitive host :

• intermediate host:

• infective stage for definitive host:

• dogs

• 1st intermediate host : snail

  • 2nd intermediate host : salmon (or trout)

• metacercaria in fish

• Nanophyetus salmincole -- Salmon poisoning fluke of dogs 

  • Fluke carries _________

    • Causes salmon poisoning disease 

  • Fluke itself produces _______

  • Pacific Northwest

• Neorickettsia helminthoeca 

• little to no disease 

Paragonimus spp.

lung fluke of dogs and cats

Paragonimus spp.

• definitive host :

• intermediate host:

• infective stage for definitive host:

• dogs, cats

• 1st intermediate host : water snail

  • 2nd intermediate host : crawfish or carb

• metacercaria in crustacean tissue

Paragonimus spp.

• migrate to _________

• eggs coughed up and ______

• can be _____

• lungs and from cysts

• swallowed

• fatal

Cercarial Dermatitis

• “ _____”

• slow onset of lethargy, ____, ____

• then severe liver and ___ _____

• _____ if not treated

• “swimmers itch

• diarrhea, +/- melena

• GI disease

• fatal

Hymenolepsis nana

dwarf tapeworm

Hymenolepsis nana

• mainly ______

• _____ life cycle

zoonotic

• rodents (sometimes humans)

• direct

Macracanthorhynchus hirudinaceus

thorny headed worm of swine

• can cause perforation, peritonitis, death

Macracanthorhynchus hirudinaceus

• life cycle:

• definitive host :

• intermediate host:

• transmission:

• indirect

• pigs

• beetle

• ingestion of IH

Onicola canis

thorny headed worm of dogs

Onicola canis

• life cycle :

• definitive host :

• intermediate host:

• transmission :

• indirect

• dogs, wild carnivores

• beetle

  • paratenic host : armadillo

• ingestion of IH or PH

Onicola canis

• attaches to _____ _____

• causes same symptoms as ________

• north and south america

• intestinal mucosa

• swine species

Hymenolepsis diminuta

rat tapeworm

• mice, rate, gerbils, hamsters, chinchillas

Hymenolepsis diminuta

• ingestion of infected _____, ____, _____, _____, etc

fleas, beetle, mealworms, cockroaches,