Phylum Platyhelminthes: Flukes (Cram)

What are the two classes of flatworms

1. Class Trematoda

2. Class Cestoda

What is the common name for class Trematoda? Remember: It was a fluke I survived the tremor

Flukes

What is the common name for class Cestoda?

Tapeworms

Term that describes how most Platyhelminths have both male and female reproductive organs

Hermaphroditic

Do Platyhelminths move around to feed?

No

What two structures can Platyhelminths have to attach themselves to the host?

1. Ventral sucker

2. Oral sucker

What type of lifestyle do Platyhelminths have?

Indirect

How are flukes flattened, what do they resemble?

Dorso–ventrally, leaf

Why are the cecal contents of flukes known as "fluke puke"

Becaused they lack an anus, cecal contents are regurgitated

How do you test for the presence of fluke eggs in feces?

Sedimentation, too heavy to float

Where do fluke eggs usually need to land in order to hatch?

Water

Fluke larva in egg hatches

Miracidium

What does a miracidium have to do in its first 24 hours in order to survive?

Find an intermediate host (IH)

Miracidium penetrates the IH, becomes sac–like, containing many germinal cells

Sporocyst

Each germinal cell in a sporocyst turns in 5–8 of these

Redia (rediae plural)

Tadpole–like form after redia

Cercaria

What are the three things a cercaria can do?

1. Go into another IH, become metacercaria

2. Encyst on vegetation as a metacercaria

3. Go directly into DH, metacercaria stage skipped

What is the genus species known as the common liver fluke?

Fasciola hepatica

What are the two most important definitive hosts of Fasciola hepatica?

Sheep and cattle

What is the intermediate host for Fasciola hepatica?

Water snails

What is the site of adult Fasciola hepatica in the DH?

Bile ducts

What is the site of immature Fasciola hepatica in the DH?

Liver parenchyma

What is a major anatomical feature of Fasciola hepatica?

Anterior projecting cone

Cap on the end of fluke eggs

Operculum

How long is the prepatent period for Fasciola hepatica?

10–12 weeks

Disease developed due to the migration of Fasciola hepatica

Black disease (Clostridum novyi B)

True or false: Fasciola hepatica cause anemia

True. They are avid bloodsuckers

What should you NOT treat flukes with?

Ivermectin

What should you use to treat flukes?

Anthelmintics

What genus species is commonly known as the giant liver fluke?

Fascioloides magna

What are the four domesticated definitive host species of Fascioloides magna?

Cattle, sheep, llama, pig

What is the intermediate host of Fascioloides magna?

Water snail

Which is the largest fluke of any domesticated species?

Fascioloides magna

What is the prepatent period for Fascioloides magna in cattle?

30–32 weeks

How are Fascioloides magna encapsulated in deer?

Thin, fibrous capsules connected to bile ducts, this allows the passage of eggs into the feces

How are Fascioloides magna encapsulated in cattle?

Thick walled, fibrous capsule that occludes bile ducts. Eggs can't pass into the environment

How are Fascioloides magna encapsulated in sheep?

They aren't. Flukes can migrate freely, causing extensive liver damage

What can farmers do to their feilds in spring to decrease the larval stages of Fascioloides magna?

Controlled burning

What genus species is commonly known as the lancet fluke?

Dicrocoelium dendriticum

What are the three domestic definitive host species of Dicrocoelium dendriticum?

Sheep, goats, cattle

What are the two intermediate hosts of Dicrocoelium dendriticum?

1. Land snails\n2. Brown ants

What are the two sites for adult Dicrocoelium dendriticum in the definitive host?

1. Bile ducts\n2. Gallbladder

What is the prepatent period for Dicrocoelium dendriticum?

10–12 weeks

True or false: Dicrocoelium dendriticum are highly pathogenic, it usually takes very few flukes to cause symptoms

False. It is not uncommon for 14,000 adult flukes to infect a host at one time

What species is common in sled dogs or dogs that eat raw fish?

Metorchis conjunctis

What are the two domestic definitive host species for Metorchis conjunctis?

Dogs, cats

What are the two intermediate hosts of Metorchis conjunctis?

1. Water snails\n2. Wide variety of fish species

What is the site of adult Metorchis conjunctis flukes in the definitive host?

Bile ducts

What is the prepatent period for Metorchis conjunctis?

16 days

What genus species is known as the salmon poisoning fluke?

Nanophyetus salmincola

What are the two domestic definitive host species for Nanophyetus salmincola?

Dogs, cats

What are the two intermediate hosts for Nanophyetus salmincola?

1. Water snails\n2. Salmon or trout

What is the site of adult Nanophyetus salmincola flukes in the definitive host?

Small intestine

Which is the smallest fluke of domesticated species?

Nanophyetus salmincola

What is the prepatent period for Nanophyetus salmincola in dogs?

5–8 days

True or false: Nanophyetus salmincola are highly pathogenic, they cause fever, lack of appetite, vomiting, and diarrhea which can be fatal

False. The fluke itself is relatively harmless, the pathogenic effects are due to them being vectors of a Rickettsia bacteria

What is the genus species commonly known as the lung fluke?

Paragonimus kellicotti

What are the two domestic definitive host species for Paragonimus kellicotti?

Dogs, cats

What are the two intermediate hosts for Paragonimus kellicotti?

1. Water snails \n2. Crustaceans (crabs, crayfish, etc.)

What do Paragonimus kellicotti flukes cause in the lung parenchyma?

Cysts

What is the genus of fluke known as the intestinal fluke?

Alaria species

What are the two domestic definitive host species for Alaria spp?

Dogs, cats

What are the two intermediate hosts for Alaria spp?

1. Water snails \n2. Tadpoles (these may be eaten by frogs, snakes, etc. But no futher development takes place)

What is the site of adult Alaria spp flukes in the definitive host?

Small intestine

Are Alaria spp. generally very pathogenic?

No

What are two anthelmintics commonly used for the treatment of flukes?

1. Albendazole2. Fenbendazole