Parasitlogy 2nd

1. FASCIOLA HEPATICA
By
WAqAS AHmAd SHAmS

2. ‫الرحيم‬ ‫الرحمن‬ ‫ال‬ ‫بسم‬

3. Scientific Classification
Kingdom: Animalia
Phylum: Platyhelminthes
Class: Trematoda
Subclass: Digenea
Prder Echinostomida
Family: Fasciolidea
Genus: Fascio la
Species:he pitica

4. General Information
- Commonly known as liver fluke
- A parasitic flatworm

5. 5
Fasciolahepatica
 Fasciolahepatica, also known as the common
liverfluke or sheep liverfluke.
 Is a parasitic flatworm of the class Trematoda,
phylum Platyhelminthes that infects liver of
various mammals, including humans.
 The disease caused by the fluke is called
fascioliasis (also known as fasciolosis).

6. Geographical Distribution
- Found in Rural areas of
temperate and tropical
regions
- Especially located in
regions with cattle and
sheep herding
- Found on every
continent with nearly 180
million people at risk and
an estimated 2.4 million
people already infected
worldwide.

7. Transmission
- Occurs through the ingestion of raw, fresh water
vegetation
- Plants become exposed to the metacercariae
when the body of water that the vegetation is
growing in becomes contaminated by eggs in
the fecal mater of the infested host
- A form of infection known as halzoun (in the
Middle East) is contracted by eating the raw
liver of an infected animal

8. Morphology
- Adult has a flat leaflike
body
- About 20-30 mm long by
8-15 mm wide
- Has an anterior
elongation where oral and
ventral suckers are
located
- Intestines are very
branched

9. Hosts
- Cattle
- Sheep
- Sometimes humans

10. Life Cycle

11. Life Cycle (Cont’d)
- The adult F. he patica lives in bile ducts of the
host’s liver
- Begin to produce eggs 2-4 months after initial
infection
- Eggs pass down the bile duct through gastrointestinal
tract and are released in the hosts feces
- Require water of temperature above 10 C to hatch
- The egg hatches and releases miracidiae within two
weeks
- These newly hatched miracidiae must find a Lymanae
snail host within 24 of hatching or they will die

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13. Life Cycle (Cont’d)
- Inside the Lymanaea miracidium loses its cilia
and develops into a sporocyst
- Each sporocyst develops into a ridia which then
burst the sporocyst and migrate to the hepato-
pancreas of the snail
- Ridia then develop into cercariae
- Cercariae attach to plant matter and encyst,
forming metacercariae which is the infective
form of the fluke
- Mammalian host consumes the vegetation with
the metacercariae which then excyst in the small
intestine

14. Life Cycle (Cont’d)
- Metacercariae burrow through the intestinal
wall, move through the peritoneal cavity and
enter the liver parenchyma
- Immature flukes migrate through the liver
patanchyma for 6-8 weeks giving rise to acute
symptoms
- Once mature they settle in the bile ducts and
begin to produce their own eggs after about a
month.

15. http://www.cdfound.to.it/hTML/fh2a.htm

16. Four Symptomatic Patterns
- Acute Phase
- Cronic Phase
- Halzoun
- Ectopic Infection

17. Acute Phase
- Rarely seen in humans
- Fever, tender hepatomegaly, and abdominal
pain are frequent symptoms.
- Vomiting, diarrhea, and anemia may also be
present

18. Cronic Phase
- More common in human population
- Symptoms include: bilary cholic, abdominal
pain, tender hepatomegaly, and jaundice
- In children: severe anemia is common
- Inflammation of the bile ducts eventually leads
to fibrosis and a condition called “pipestem liver”
- Severe infections can lead to death

19. Halzoun & Ectopic Infection
- Occurs when an
individual consumes
infected raw liver
- The adult worms can
cause considerable pain,
edema, and bleeding
that can interfere with
respiration
- Adults can live in biliary
ducts and cause
symptoms for up to 10
years.
- In frequent, but can occur
in peritoneal cavity,
intestinal wall, lungs,
subcutaneous tissue,
and very rarely in other
locations.

20. Diagnostic Tests
- Most widely used form of diagnosis is the directly
observed presence of F. hepatica eggs either in a stool
sample, duodenal aspirate or biliary aspirate
- Flukes do not begin to produce eggs until about 4
months after infection, so you cannot test the stool
- Prior to 4 months: serological tests can be used
- FAST-ELISA (most popular)
- Ultrasound can be used to visualize adult flukes in the
bile ducts
- CT scan can reveal burrow tracts made by the worms

21. Treatment
- Many countries use a 5-10 day course of oral
bithionol at 30mg/kg body weight
- Triclabendazole is a preferred antihelmintic
agent, but is unavailable in most countries.
- The resistance is rising to this drug
- Along with pharmaceutical therapy, surgery may
be necessary in very extreme cases to clear the
biliary tract

22. Control Methods
- Education
- Molluscicides: application of malluscicides to
decrease the population of Lymnaea snails
- Chemotherapy

23. Review Questions
- 1. What is the average size of an adult F. he patica?
a. 20 mm x 5mm
b. 30 mm x 13 mm
c. 10 mm x 5 mm
2. What continent can F. He patica be found?
a. Africa
b. Asia
c. America
d. All of the above

24. Review (Cont’d)
- 3. What is the most effective way to treat fascioliasis?
a. bithionol
b. flagyl
c. triclabendazole

25. References
- “Fascioliasis” Retrieved: 2/19/2007
http://www.stanford.edu/class/humbio103/fascioliasi
- “Fasciola hepatica.” Wikipedia, free
encyclopedia. Retrieved: 2/19/2007
http://en.wikipedia.org/wiki/Fasciola_hepatica
- “Fasciola hepatica.” Retrieved: 2/19/2007
http://www.cdfound.to.it/html/fas1.htm

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