Student of TSMU A Parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism amp which causes harm to the host without immediately killing it ID: 932861
Download Presentation The PPT/PDF document "FASCIOLA HEPATICA MUZAFFAR KHAN ALAM KHA..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
FASCIOLA HEPATICA
MUZAFFAR KHAN ALAM KHAN
Student of TSMU
Slide2A Parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism & which causes harm to the host without immediately killing it.
Every free-living species has its own unique species of parasite, so the number of parasitic species greatly exceeds the number of free living species.
Parasite
Slide3PARASITOLOGY & MEDICAL PARASITOLOGY:
It is the study of parasites, their hosts & the relationship between them.
One of the largest fields in parasitolgy, medical parasitology is the subhect which deals with the parasites that infect humans, the diseases caused by them, clinical picture and the response generated by humans against them. It is also concerned with the various methods of their diagnosis, treatment & finally their prevention & control.
Slide4Scientific Classification
Kingdom: Animalia
Phylum: Platyhelminthes Class: Trematoda Subclass: Digenea Order: Echinostomida Family: Fasciolidea Genus: Fasciola Species: hepatica
Slide5TREMATODES-FLAT WORMS(FLUKES)
Opisthorchis
O. sinensisO. felineusO. viveriniParagonimus P. westermani
P.
kellicotti
E
chinostoma
Schistosoma
S.
mansoni
S.
hematobium
S.
japonicum
Fasciolopsis
Fasciolopsis
buski
Fasiola
Fasiola
hepatica
Fasiola
gigantica
Slide6Trematodes: Morphological Features
Mouth connects to pharynx, leads to esophagus, bifurcates into 2 ceca
No anus: releases cecal contents back through mouth into tissue it infectsCecal contents can be seen in histopathologic section and are colloquially referred to as “fluke puke”Also possess and acetabulum, or ventral sucker – holdfast organ not associated with feeding Near anterior end, mouth is surrounded by muscular oral sucker
Slide7Trematodes: ReproductionWith exception of schistosomes (blood flukes) all flukes are hermaphroditic
Each fluke possesses both sex organs
Self-fertilization usually takes place, but cross-fertalization can also occur
Slide8Fasciola hepatica
Fasciola hepatica
, also known as the common liver fluke or sheep liver fluke. 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). F. hepatica is world-wide distributed and causes great economic losses in sheep and cattle.
Slide9Definitive host:
Sheep
CattleHumans (Accidental)Other Mammals Intermediate host:Fresh Water Snail Geographic Range:Cosmopolitan; anywhere sheep and cattle are raised
Slide10Slide11Morphology of adult Fasciola hepatica
acetabulum
Slide12Morphology
:
(Angus, 1978)SpecieSizeShapeF.hepatica5cm length/1.5cm wideLeaf shape with prominent shoulders
F.gigantica
7.5cm length/1.2cm wide
Leaf shape with scarcely perceptible
shoulders
Slide13Dr.T.V.Rao MD
13
Slide14Life cycle outside the animal
Eggs hatch in spring (>10 °C) to release
miracidia which must penetrate a mud snail (Lymnaea [syn. Galba] truncatula) within 3 hours Develop inside snail Cercariae emerge from snail Encyst on grass (metacercariae) Infection of a snail with one miracidium can produce over 600 metacercariae
Slide15Life cycle inside the animal
Once ingested metacercariae excyst in SI and immature fluke migrate through the gut wall to penetrate the liver
Tunnel through liver for 6-8 weeks before entering bile ducts where they reach maturity Time from infection of cattle/sheep to adult egg-laying fluke is 10-12 weeks Little or no development of immunity
Slide16Cycle of Events in Fasciola hepatica
The life cycle of Fasciola hepatica starts when a female lays eggs in the liver of an infected human. Immature eggs are discharged in the biliary ducts and taken out in the feces. If landed in water, the eggs become embryonated and develop larvae called miracidia. A miracidium invades an aquatic snail and develops into cercaria, a larva that is capable of swimming with its large tail.
Dr.T.V.Rao MD16
Slide17The cercaria exits and finds aquatic vegetation where it forms a cyst called Metacercariae. A human eats the raw freshwater plant containing the cyst. The Metacercariae excysts in the first part of the small intestine, duodenum. It then penetrates the intestinal wall and gets into the peritoneal cavity.
Cycle of events in infection
Dr.T.V.Rao MD17
Slide18Cycle of events in infectionIt finds the liver and starts eating liver cells. This happens only a few days after the initial contact with the parasite. Usually the larva spends a few weeks just browsing and eating the liver. Then it relocates to the bile duct where it begins its final stage and becomes an adult. It takes about three months for the Metacercariae to develop into an adult. Adults are about 3 cm long and 1 cm wide. Adult females can produce up to 25000 eggs per day.
Dr.T.V.Rao MD
18
Slide19Ingestion MetacercariaeEx-cyst in DuodenumBurrows through Intestinal Wall
Enters Peritoneal Cavity
Migrates to LiverProgress of InfectionDr.T.V.Rao MD19
Slide20MACROSCOPIC & MICROSCOPIC EXAMINATION
Slide21Egg capsule with emerging miracidium of Fasciola hepatica. 400x
Slide22F.hepatica
, egg: eggs measure 140 by 80 µm and are
operculated. The colour is yellow to brown. (Formol-ether concentration).
Slide23egg capsule with emerging miracidium
of
Fasciola hepatica
. 400x
unembryonated egg
capsule of
F. hepatica
. earlier stage of development. 400x
embryonated egg
capsule of
Fasciola hepatica.
So-named because the
miracidium
is fully formed and ready to emerge. The operculum can be seen to the left. 400x
Slide24Redia and cercaria of
Fasciola hepatica
Miracidium of
Fasciola hepatica
. This ciliated, non-feeding larval stage, has about 24 hours to find its specific snail host, such as
Fossaria
modicella
or
Stagnicola bulimoides.
400x
Slide25The ova
Length 130-145 µm
Width 70-90 µm
Regular ellipse
Thin shell
Operculum at one pole
Granular yellowish-brown contents filling whole egg
Slide26The Adult
one of the largest flukes in the world.
20 -30mm in length and 13 mm in width Leaf shape characteristic with the anterior end broader than the posterior end and an anterior cone-shaped projection. Possesses a powerful oral sucker at the anterior cone and a ventral sucker at the base of the cone attach to the lining of the biliary ducts.monoecious - possesses ovaries and testes which are highly branched and allow for individual flukes to produce eggs independently.
Slide27A stained adult
Fasciola hepatica
; approximate length = 20 mm. The internal organs are highly branched, thus making it very difficult to differentiate the various internal organs
All of their major systems are branched, including the intestine, testes, and ovary.
Slide28Slide29F.hepatica
,
adult worm, macroscopic examination: adults measure 2-5 cm by 8-13 mm, are flat, oval in shape with a cephalic cone containing the oral sucker.The adults live in biliary ducts for up to 10 years.
Fasciola
hepatica
, living adult in bile duct of sheep.
Slide30F.hepatica
, adult worm, liver biopsy: after
excistation in the small intestine, metacercariae penetrate the intestinal wall and the Glisson capsule, cross the liver parenchima to the bile ducts.Eggs can be found in
faeces
3-4 months after penetration.
Slide31F.hepatica
, adult worm, macroscopic
examination: higher magnification: particular of the cephalic cone with the oral sucker.
Slide32SYMPTOMS:
Slide33The first stage:
prepatent or larval period: Abdominal Pain Fever Backache, headache Chills Weight loss Urticaria Eosinophilia, elevation of AST, ALT Cough and chest discomfort
The second stage: patent or
biliary
period:
Intermittent right upper quadrant pain
Enlarged, tender liver
Diarrhea
Eosinophilia
Complications:
Anemia,
cholangitis
,
biliary
obstruction,
subcapsular
liver hematomas,
hemoperitoneum
Symptoms
Slide34Condemned Liver
Annual condemnation of livers of 3-4% of cattle at $3-5 each due to parasites
.
Adult-
Biliary
hyperplasia, dilatation, fibrosis, calcification
Migration-Diffuse fibrosis, shrunken ventral lobe
Slide35The course of infection passes through three phases:
• The
acute phase • The chronic phase • The obstructive phasePathology / clinical manifestations are related to the phase
Slide36Acute Phase:
Rarely seen in humans and occurs only when a
large number of metacercariae are ingested at once. Fever, tender hepatomegaly, and abdominal pain are the most frequent symptoms of this stage of infection vomiting, diarrhea, urticaria (hives), anemia, may be present. Caused by the migration of the F. hepatica larvae throughout the liver parenchyma. The larvae penetrate the liver capsule and begin to produce symptoms 4-7 days after ingestion. Migration and acute phase continues for 6-8 weeks until the larvae mature and settle in the bile ducts.
Slide37The acute phase:
Coincides with migration of the immature flukes through the peritoneal cavity, penetrating liver capsule then through liver parenchyma till they reach the bile ducts.
liver
Slide38Symptoms :
Acute symptoms Asymptomatic (unusual) Severe illness (prostration & jaundice) (unusual)
Acute dyspepsia
Prolonged high fever
Hepatomegaly/ abdominal pain in the right hypochondrium
Urticaria
Peripheral eosinophilia, up to 80%
.
Anaemia
Slide39Cont..
Chronic Phase:
more common in human include biliary cholic, abdominal pain, tender hepatomegaly, and jaundice. In children, severe anemia - common result of infectionbiliary obstruction and inflammation caused by the presence of the large adult worms and their metabolic waste in the bile ducts. Inflammation of the bile ducts leads to fibrosis and a condition called "pipestem liver", (white appearance of the biliary ducts after fibrosis). The final outcome portal cirrhosis and even death.
Slide40The
chronic
phase, coincides with the presence of the flukes in the bile ducts The life span of the parasite is 10-13 yearsPathology tends to be mild
Slide41Symptoms
: Asymptomatic Few gastrointestinal symptoms Intermittent fever with persistent prominent eosinophilia Recurrences of the acute signs & symptoms Recurrent cholangitis
Slide42Obstructive phase
(heavy / prolonged infection) Coincides with epithelial changes in the bile ducts due to irritation of the epithelium by the spines& the activity of proline
Slide43Diagnosis
Fasciola
is diagnosed by fecal sedimentation examinationEggs are large, operculated and golden in color
Slide44DIAGNOSIS:
Slide45Laboratory diagnosis
The definitive and most widely used form of diagnosis is the directly observed presence of Fasciola hepatica eggs either in a
stool sample, duodenal aspirate or biliary aspirate. However, the flukes do not begin to produce eggs until roughly 4 months after infection. Until this time and in the case of ectopic infections where eggs are not present in the stool, serological tests can be used, the FAST-ELISA being the most popular. It has a sensitivity of 95% and can detect specific F. hepatic antibodies as early as 2 weeks after infection .Ultrasound can be used to visualize the adult flukes in the bile ducts CT scan may reveal the burrow tracts made by the worms and dilation of the bile ducts.
Slide46Computed tomography (CT) and magnetic-resonance-imaging (MRI)are used for further characterization of the
lesion.They
are indispensable for the evaluation of extrahepatic affection in AE and they are used for a preoperative evaluation.CT best depicts the typical calcifications and it is used for follow-up examinations at longer intervalls. For serology an ELISA was established based on the purified E.multilocularis carbohydrate antigen Em2 (derived from the laminated layer). It is the reference test for diagnosis and it may allow discrimination of AE from E.granulosus infection.However, in a significant percentage of cases the two species can not be differentiated simply by serological means.
Slide47Halzoun
: worm
settles in the pharynx. Occurs when an individual consumes infected raw liver The young adult worms then attach themselves to the pharyngeal mucosa causes considerable pain, edema, and bleeding that can interfere with respiration. The adults can live in the biliary ducts, causing symptoms for up to 10 years. Ectopic Infection: Ectopic infections through normal transmission are infrequent but can occur in the peritoneal cavity, intestinal wall, lungs, subcutaneous tissue, and very rarely in other locations.
Slide48Fasciola
hepatica:
although direct diagnosis by observation of eggs in faecal smears it the reference method, indirect diagnostic tests such as IF may allow diagnosis when direct observation is negative. Immunodiagnosis by indirect mmunofluorescence.
Antigen: frozen sections of
Fasciola
hepatica.
epidemiology
49
Infection begins when Metacercariae infected aquatic vegetation is eaten or when water containing Metacercariae is drunk. Humans are often infected by eating watercress. Human infections occur in parts of Europe, northern Africa, Cuba, South America, and other locales. It is one of the most important disease agents of domestic stock throughout the world and shows promise of remaining so for years to come.
Slide50Treatment
Bithional
Highly EffectiveLarge DoseHigh CostLong Treatment PeriodTriclabendazoleEasier to Use1-2 Oral Doses in 24 hrsVirtually 100% EffectiveSurgery50
Slide51Prevention
The presence of a substantial reservoir
- keep domestic animal herds separate from the growing sites of aquatic. This limits the risk of contaminating the vegetation and thus decreases both human infection and the animal reservoirThe presence of the intermediate host, the Lymanaea snails - application of molluscicides to decrease the population of Lymnaea snails.The opportunity for water source contamination by human and non-human hosts Dietary practices that include the consumption of raw, untreated aquatic vegetation.
Slide52Slide53References:www.slideshare.net