TREMATODA TREMATODA Fasciolopsis buskiFasciolopsis buski

IntroductionIntroduction Fasciolopsis buskiFasciolopsis buski lives in the small lives in the small

intestine of humans and pigs. intestine of humans and pigs. Measuring up to 80 mm in lengthMeasuring up to 80 mm in length largest trematodes found in humanslargest trematodes found in humans Geographic Distribution:Geographic Distribution:

Asia and the Indian subcontinent, Asia and the Indian subcontinent, especially in areas where humans especially in areas where humans raise pigs and consume freshwater raise pigs and consume freshwater plants.plants.

As with many other parasites that As with many other parasites that infect humans, pigs serve as a infect humans, pigs serve as a reservoir hostreservoir host

Can cause FascioslopsiasisCan cause Fascioslopsiasis

MORPHOLOGY : ADULT MORPHOLOGY : ADULT The adult flukes range in size: 20 to The adult flukes range in size: 20 to

75 mm by 8 to 20 mm. 75 mm by 8 to 20 mm. No cephalic cone, acetabulum larger No cephalic cone, acetabulum larger

than oral sucker. than oral sucker. Testis posterior & branched.Testis posterior & branched. Attach themselves to the tissues of Attach themselves to the tissues of

the small intestine of the host by the small intestine of the host by means of ventral suckers; the sites of means of ventral suckers; the sites of attachment may later ulcerate and attachment may later ulcerate and form abscesses.form abscesses.

The adult flukes range in size: 20 to 75 mm by 8 to 20 mm.

Fasciolopsis Buski adult;approximate length = 50 mm

Typical gymnocephalus cercaria of a fascioliid.  This is a ventral view showing the

spherical acetabulum framed by the two branches of the caeca.  This Fasciolopsis

buski cercaria is indistinguishable from the cercaria of Fasciola hepatica.  100x

This photo is to compare the sizes of Fasciolopsis buski (left) and Fasciola hepatica (right), 2x.

Egg is practically indistinguishable Egg is practically indistinguishable from those of from those of Fasciola hepaticaFasciola hepatica. .

The eggs are ellipsoidal, with a thin The eggs are ellipsoidal, with a thin shell, and a usually small, indistinct shell, and a usually small, indistinct operculum, range in size: 130 to 159 operculum, range in size: 130 to 159 µm by 78 to 98 µm.µm by 78 to 98 µm.

MORPHOLOGY : EGGMORPHOLOGY : EGG

Life cycleLife cycle

Cont..Cont.. Immature eggs are discharged into the intestine and stool.Immature eggs are discharged into the intestine and stool. Eggs become embryonated in water , eggs release miracidia , Eggs become embryonated in water , eggs release miracidia ,

which invade a suitable snail intermediate host. which invade a suitable snail intermediate host. In the snail the parasites undergo several developmental In the snail the parasites undergo several developmental

stages (sporocysts, rediae, and cercariae ). stages (sporocysts, rediae, and cercariae ). The cercariae are released from the snail and encyst as The cercariae are released from the snail and encyst as

metacercariae on aquatic plants. metacercariae on aquatic plants. The mammalian hosts become infected by ingesting The mammalian hosts become infected by ingesting

metacercariae on the aquatic plants. metacercariae on the aquatic plants. After ingestion, the metacercariae excyst in the duodenum After ingestion, the metacercariae excyst in the duodenum

and attach to the intestinal wall.and attach to the intestinal wall. There they develop into adult flukes (20 to 75 mm by 8 to 20 There they develop into adult flukes (20 to 75 mm by 8 to 20

mm) in approximately 3 months, attached to the intestinal mm) in approximately 3 months, attached to the intestinal wall of the mammalian hosts (humans and pigs).wall of the mammalian hosts (humans and pigs).

The adults have a life span of about one year.The adults have a life span of about one year.

Pathogenicity & Pathogenicity & SymptomSymptom

Most infections are light and Most infections are light and asymptomatic. asymptomatic.

In heavier infections, symptoms include In heavier infections, symptoms include diarrhea, abdominal pain, fever, ascites, diarrhea, abdominal pain, fever, ascites, and intestinal obstruction. and intestinal obstruction.

Chronic infections with this parasite Chronic infections with this parasite lead to inflammation, ulceration, lead to inflammation, ulceration, hemorrhage, and abscesses of the small hemorrhage, and abscesses of the small intestine, and these can ultimately lead intestine, and these can ultimately lead to the host's death. to the host's death.

Laboratory Diagnosis Laboratory Diagnosis Microscopic identification of eggs, or Microscopic identification of eggs, or

more rarely of the adult flukes, in the more rarely of the adult flukes, in the stool or vomitus is the basis of stool or vomitus is the basis of specific diagnosis. specific diagnosis.

The eggs are indistinguishable from The eggs are indistinguishable from those of those of Fasciola hepaticaFasciola hepatica..

TreatmentTreatment : : Praziquantel Praziquantel

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