Fascioloa gigantica 20%

Question 1

What are they (fascioloa)- species affected

Answer 1

Large flukes in bile duct of animals and man
Parasitic flatworm – causes tropical fascioliasis
Affects sheep, cattle, and other grazing ruminant mammals.

Question 2

Reservoir hosts (fascioloa)

Answer 2

Sheep, goats, cattle, roe deer and lagomorphs. Fasciola sp. are not found in North American deer.

Question 3

Life cycle/ transmission- escape from host (fascioloa)

Answer 3

Eggs (Transported with feces) – eggs hatch > miracidium infect snail intermediate host > pathogenesis in 24 h sporocyst – redia – cercaria – gets outside the snail> find aquatic plants, encyst and become metacercaria > infection of host (eats plants with metacercariae)> adult stage produces eggs> Metacercariae move through the intest wall and peritoneal cavity to the liver where adults mature in biliary ducts of the liver> Eggs are passed thru bile ducts into the intestine where they are then passed in the feces After ingestion it takes 3 – 4 months for adult flukes to become mature and begin producing eggs

Question 4

Incubation period (fascioloa)

Answer 4

Highly variable depending on worm burden. Prepatency is approximately 2-4 months.

Question 5

Age, season (fascioloa)

Answer 5

Rainy season
All ages equally susceptible on first exposure. Considerable resistance develops in adult reservoir animals which are reinfected annually.
Young animals carry the largest worm burdens and produce the greatest numbers of eggs. Humans are equally susceptible at all ages.

Question 6

clinical signs (fascioloa)

Answer 6

Acute: damage extensive, liver enlarged and friable with fibrinous deposits on capsule, can see migratory tracts, surface has uneven appearance
Chronic: Cirrhosis develops, damaged bile ducts enlarged or cystic and have thickened, fibrosed walls
Cattle – duct walls thickened and calcified (does not happen in sheep)
Aberrant migrations common in cattle – encapsulated flukes may be found in lungs

Question 7

Diagnosis (fasciola)

Answer 7

Dx: eggs on fecal (large yellow golden brown operculated eggs) , ELISA (europe), GGT elevations

Question 8

Treatment (fascioloa)

Answer 8

Treatment of domestic livestock- Triclabendazole, clorsulon (cattle and sheep only), albendazole, netobimin, closantel, rafoxanide, oxyclozanide particularly ruminants in endemic areas.

Question 9

Prevention (fasciola)

Answer 9

Discourage consumption of aquatic vegetation.
Snail control with chemicals in areas associated with permanent waters
Removal flukes in affected animals
Prevention of livestock access to snail infested pasture

Question 10

Zoonotic (fascioloa)

Answer 10

yes

Question 11

Mortality (fascioloa)

Answer 11

Human mortality is rare. Animal mortality depends on the parasitic burden and development of clostridial toxins.

Cattle which have not been clostridium vaccinated may suffer high mortality rates from bacillary hemoglobinuria, whereas sheep which have not been vaccinated may suffer heavy losses from black disease.