2 Fasciolosis of mammals (family Fasciolidae: Fasciola, Fascioloides, Fasciolopsis)

Question 1

Fasciola hepatica
Morphology

Answer 1

Size = Large, 30mm x 13mm
Shape = Leaf like, anterior more broad with cone shaped projection, distinct shoulders
Organs =
-Testes: branched and tandem (one above the other)
-Ovary: branched and pretesticular
-Cirrus and cirrus pouch: well developed
-Genital pore: anterior to acetbulum
-Uterus: short and anterior to ovary
-Vitelline follicles: small, abundant and well distributed
-Organs of attachment: oral sucker and acetabulum,close together anteriorly

Question 2

Main Species of Fasciola

Answer 2

• Fasciola hepatica - Common liver fluke (world wide) zoonotic
• Fasciola gigantic - Tropical liver fluke (Asia and africa - tropical regions)

Question 3

Fasciola hepatica
IH

Answer 3

Fresh-water snails - Lymnea

Question 4

Fasciola hepatica
FH

Answer 4

Ruminants
Equids
Man
Rodents
+other

Question 5

Fasciola hepatica
Eggs

Answer 5

• Large
• Oval, symmetrical
• 2x thin shells w/operculum
• Unembryonated
• Yellow/Brown in colour

Question 6

Fasciola hepatica
Location

Answer 6

Adults = Bile ducst, gall bladder
Juvenile = Abdominal cavity, liver parenchyma

Question 7

Fasciola hepatica
Life cycle

Answer 7

1. Adult fluke in bile duct shed eggs with bile, unembryonated eggs go into enviroment with feces
2. In environment, Miracidium develops inside the egg
3. Miracidium hatches in the water (operculum) finds IH (snail) and penetrates it
4. In IH, as Miracidium penetrates it becomes a Sporocyst, germinal cells become Redia and embryos in Redia become Cercaria-exit the IH
5. In environment, Cercaria finds a suitble place to encyst on waterplants
6. Cercaria adheres to the plant and encyst as Metacercaria = Infective stage
7. FH eats the water plant with Metacercaria
8. Metacercaria excyst in the small intestine, burrows through the intestinal wall into peritoneal cavity, going through tissue and reaches the liver capsule
9. Young flukes tunnel through the liver parenchyma (6-8 weeks)
10. Finally entering the bile duct and reach sexual maturity - Adults

Question 8

Fasciola hepatica
LC stages - length

Answer 8

1. Embryogony = 8 weeks/avg.56 days
2. Parthenogony = 6-7 weeks, optimal conditions
3. Cystogony = 2-3 days
4. Maritogony = 6-8 weeks

Entire life cycle takes 5/6 months

Question 9

Fasciola hepatica
Pathogenesis

Answer 9

Depends on amount of Metacercaria ingested
* 1st phase: migration of juvenile form to liver/bile ducts, causing parenchymal and blood vessel damage (Toxic products: Protelytic enzymes), internal bleeding and decreased liver function
* 2nd phase: Adult-Haematophagia, damage tothe mucosa by cuticular thorns

Question 10

Fasciola hepatica
Clinical signs

Answer 10

Submandibular oedema, emaciation, anaemia
* Acute: Hepatitis traumatica, can be fatal if enough amount of Metacercaria are ingested
* Subacute: Cholangitis and lesions in bile duct, enlargement of liver (ingested over sometime)
* Chronic: Anaemia, hypoalbuminema, liver failure (icterus). Common in sheep,moderate ingestion

Question 11

Fasciola hepatica
Treatment

Answer 11

Acute, young flukes in liver
Triclabendazole
Subacute or Chronic
Oxycloxanide

Question 12

Fasciola hepatica
Prevention

Answer 12

Kill IH - molluscicide

Question 13

Fasciola hepatica
Diagnosis

Answer 13

1. Fecal examination - Sedimentation method
2. Serology
3. ELISA

Question 14

Fasciola gigantica
Morphology

Answer 14

Size: Larger than F. hepatica
Other is similar to F. hepatica

Question 15

Fasciola gigantica
Pathogenesis

Answer 15

Liver fibrosis, Cholangitis

Question 16

Fasciola gigantica
Location

Answer 16

Bile ducts