Bovine Trematodes

Question 1

Fasciola hepatica-Common Name

Answer 1

Liver fluke

Question 2

Fasciola hepatica-Hosts

Answer 2

DH: cattle, sheep, goats, humans
IH: snails

Question 3

Fasciola hepatica-Identification

Answer 3

Adult: leaf shaped, 3cm, brownish, broader anterior than posterior, oral and ventral suckers
Eggs: 130um, yellow brown, operculum

Question 4

Fasciola hepatica-Life Cycle

Answer 4

Indirect. PPP = 2-3 mths
Eggs passed in feces→ embroyate in water→ release miracidia that invade snail→ cercariae released from snail→ encyst as metacercariae on aquatic vegetation→ DH infected by ingesting the metacercariae on water plants→ excyst in duodenum and migrate through intestinal wall→ through peritoneal cavity to biliary ducts in liver

Question 5

Fasciola hepatica-Site of Infection

Answer 5

Bile ducts in liver

Question 6

Fasciola hepatica-Pathogenesis and Lesions/Clinical Signs

Answer 6

Immature flukes migrate and feed; fibrosis replaces necrotic tracts
Adults consume blood, irritate host, cause “pipestem liver”
Chronic fasciolosis associated with mature flukes in bile ducts

Question 7

Fasciola hepatica-Diagnosis

Answer 7

Quantitative sedimentation
Necropsy
ELISA bulk milk
Elevated globulin, elevated albumin, elevated GGT

Question 8

Fasciola hepatica-Treatment and Prevention

Answer 8

Flukicides, snail control and management

Question 9

Fascioloides magna-Common Name

Answer 9

Large American liver fluke, Deer fluke

Question 10

Fascioloides magna-Hosts

Answer 10

DH: white-tailed deer etc.
Dead end hosts: cattle, moose, sika deer and bison
Aberrant hosts: sheep, goats and roe deer
IH: snails

Question 11

Fascioloides magna-Identification

Answer 11

Adults: 10cm, large, oval fluke, thick and flesh colored
Eggs: 130um, yellow brown with operculum

Question 12

Fascioloides magna-Life Cycle

Answer 12

Indirect. PPP = 8mths
similar to F. hepatica but juvenile flukes wander aimlessly, destroying liver tissue
DH: cyst forms around fluke, devel. to adults which lay eggs
Dead-end host: cyst encapsulates fluke in liver, never patent
Aberrant host: fluke migrates, no cyst forms, animal dies before patency

Question 13

Fascioloides magna-Site of Infection

Answer 13

Liver

Question 14

Fascioloides magna-Pathogenesis and Lesions/Clinical Signs

Answer 14

Deer and cattle: hepatic damage when fluke reaches liver, encapsulated by host minimizing clinical effects
Sheep and goats: continuous migration of immature flukes results in death before patent infection

Question 15

Fascioloides magna-Diagnosis

Answer 15

DH: detect eggs on fecal sedimentation

Dead end and aberrant hosts: no eggs detected

Question 16

Fascioloides magna-Treatment and Prevention

Answer 16

Anthelmintics but not approved in USA
Snail control
Land unusable for grazing of deer and livestock where deer are a natural reservoir