Exam II - Fasciolidae

Question 1

Fasciola hepatica belongs to which taxonomic group?

Answer 1

Trematodes

Question 2

For trematodes, what do we always know about the intermediate host?

Answer 2

The intermediate host is always a snail

Question 3

For trematodes, what do we always know about the diagnostic stage?

Answer 3

The diagnostic stage is always an operculated egg

Question 4

What is the common name for Fasciola hepatica?

Answer 4

liver fluke

Question 5

What is/are the final host(s) for Fasciola hepatica? Intermediate hosts?

Answer 5

Final hosts - cattle, sheep, goats, and other ruminants and humans

Intermediate hosts - snails

Question 6

Describe the appearance of the Fasciola hepatica adult

Answer 6

Adults are 3 cm, leaf shaped, brownish, broader anterior than posterior, oral and ventral suckers, suticle within spines

Question 7

Describe the Fasciola hepatica egg

Answer 7

This is one of the largest eggs you’ll encounter in feces.

Eggs are 130 um, yellow brown, with a distinct operculum

Question 8

What is the infective stage for Fasciola hepatica?

Answer 8

metacercariae

Question 9

What is significant about Fasciola hepatica eggs passed in feces?

Answer 9

They are unembryonated

Question 10

What is the PPP for Fasciola hepatica?

Answer 10

2-3 months

Question 11

What is/are the site(s) of infection for Fasciola hepatica?

Answer 11

bile ducts of the liver

Question 12

Describe any pathogenesis associated with Fasciola hepatica

Answer 12

Immature flukes migrate and feed; fibrosis replaces necrotic tracts

Adults consume blood, irritate host, cause “pipestem liver” (shown in photo below)

Chronic fasciolosis associated with mature flukes in bile ducts

Question 13

How would you diagnose Fasciola hepatica?

Answer 13

Quantitative sedimentation, ELISA bulk milk, elevated globulin

Question 14

Treatment & prevention options for Fasciola hepatica?

Answer 14

flukicides are available; snail control & management (not really feasible)

Question 15

What is the common name for Fascioloides magna?

Answer 15

deer fluke, large American liver fluke

Question 16

What is/are the host(s) for Fascioloides magna?

Answer 16

Definitive hosts are deer.

Dead-end hosts include cattle, moose, sika deer, and bison

Aberrant hosts include sheet, goats, and roe deer.

Intermediate hosts are aquatic snails

Question 17

Decribe the appearance of the Fascioloides magna adults

Answer 17

Adults are 10 cm, large oval fluke, thick & flesh covered, no anterior core.

Question 18

Describe the appearance of Fascioloides magna eggs

Answer 18

Eggsa re 130 um, yellow brown, with a distinct opeculum

Question 19

Describe the general life cycle of Fascioloides magna, compared to Fasciola hepatica

Answer 19

Similar to F. hepatica, but juvenile flukes wander aimlessly, fucking things up in the liver tissue

Question 20

Describe the life cycle of Fascioloides magna in the definitive host

Answer 20

cyst forms around fluke, develops to adult, which lay eggs

Question 21

Describe the life cycle of Fascioloides magna in the dead-end host

Answer 21

cyst encapsulates fluke in liver, never patent

Question 22

Describe the life cycle of Fascioloides magna in the aberrant host

Answer 22

fluke migrates, no cyst forms, animal dies before patency

Question 23

What is/are the site(s) of infection for Fascioloides magna?

Answer 23

liver

Question 24

Describe any pathogenesis associated with Fascioloides magna

Answer 24

In deer & cattle: parasite encapsulated by host minimizes clinical effects

In sheep and goats: continuous migration of immature flukes results in death before patent infection

Question 25

How would you diagnose Fascioloides magna?

Answer 25

Fluke eggs are not seen in dead-end and aberrant hosts, but f_ecal sedimentation will show eggs in definitive hosts_