Fasciola hepaticaCris Scott and Angel Knopick

Liver rot and you!Until 1300 thought to be a leechFrom 1970 to 1995, about 300,000 cases

were reported in 61 countries. 2.4 million are infected and 160 million more

at risk 2009 evidence of an emerging problem? In regions of Bolivia, 38% of children ages 5

to 19 may be infected.

Classification/TaxonomyKingdom: AnimaliaPhylum: PlatyhelminthesClass: TrematodaOrder: EchinostomidaFamily: FasciolidaeGenus: FasciolaSpecies: hepatica

Geographic RangeWORLDWIDE!

Human infections: Europe (especially France, Spain, Portugal), North Africa, South America (especially Bolivia), Cuba, United States

Need temperate, slow-moving, or standing water urbanization

What is affected?? aka…HOSTSDefinitive hosts: Sheep, cattle, buffalo, goats,

and rabbits

Intermediate hosts: SnailFossaria modicella or Stagnicola bulimoides

Accidental hosts: Humans??

MorphologyAdult

One of the largest flukes in the world Average is 30 mm long

and 13 mm wideLeaf/cone shaped1 posterior and 1

anterior sucker

EggAverage 140 µm long

and 75 µm wide

Life Cycle Eggs from human or other host are passed in feces: no embryo. Eggs are released into water: embryo. Eggs hatch and miracidia are released. Miracidia invade a snail (intermediate host). In the snail, the parasite

undergoes three levels of development: Sporocyst, Rediae, and Cercariae.

The cercariae are excreted from the snail and encyts as metacercariae on aquatic vegetation (lose tails).

Cattle and sheep acquire the parasite by eating the vegetation containing the metacercariae.

Humans normally become infected by eating contaminated watercress. The metacercariae excyst in the duodenum. The metacercariae migrate through the intestinal wall, the peritoneal

cavity, and the liver into the biliary ducts They develop into adult flukes, and eggs are excreted in the feces.

Fascioliasis: infection by liver flukesHumans:

Abdominal painFeverEye infection-

blindnessJaundiceEosinophiliaDiarrheaHepatomegaly

(enlarged liver)Skin rashAnemia

AnimalsAcute Type I: > 5000

ingested metacercariae, quick death without clinical signs

Acute Type II: 1000- 5000 metacercariae, slowly die

Subacute: 800 – 1000 metacercariae, anemia, weight loss, and death,

Chronic: 200 – 800 metacercariae, bottle jaw, emaciation, weight loss, and edema

DiagnosisLiver blockage coincides with the

consumption of watercressEggs in stoolFast-ELISAFalse results are possible when patients have eaten infected liver

and F. hepatica eggs pass through the fecesLiver free diet

Early diagnosis is essential to prevent irreparable damage to the liver

Control and TreatmentAvoid “wild” watercressThoroughly cook liverEducation on eating uncooked aquatic plants (kjosco)

Control host reservoir populationsControl snail populations

Triclabendazole (drug of choice) & Rafoxanide

VaccinesProteases secreted immunizing antigens

Proteases/hemoglobin: egg viability reducedCysteine proteases: worms reduced 75%

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Economic ImportanceInfection leads to mortality, reduction of milk

and meat productionLeads to secondary bacterial infectionsIn Montana, 17% of cattle livers were

infectedIn Mexico, over 400,000 out of 6 million

cattle slaughtered were confiscated

References CDC: http://www.dpd.cdc.gov/dpdx/html/fascioliasis.htm, 15 Feb

2011 NIH: http://www.ncbi.nlm.nih.gov/pubmed/8589147\, 15 Feb 2011 Wiki: http://en.wikipedia.org/wiki/Fasciolosis , 15 Feb 2011 WHO:

http://whqlibdoc.who.int/bulletin/1995/Vol73-No3/bulletin_1995_73(3)_397-401.pdf, 15 Feb 2011

WHO: http://www.who.int/neglected_diseases/integrated_media/integrated_media_fascioliasis/en/, 15 Feb 2011

Roberts, Larry S., Gerald D. Schmidt, and John Janovy. Gerald D. Schmidt & Larry S. Roberts' Foundations of Parasitology. Boston: McGraw-Hill Higher Education, 2009. Print.