Download Fasciolopsis buski

Fasciolopsis buski
A. Classification
Phylum Plathyhelminthes (flatworms)
Class Trematoda (flukes)
Family Fasciolidea
Fasciolopis buski
B. Morphology
Fasciolopis buski is considered one of the largest trematodes, with the adult
form measuring approximately 60 mm in length. Fasciolopis buski produce
about 25,000 eggs per day, each oval and measuring approximately 130 m in
length. These eggs cannot be distinguished from the eggs of Fasciola hepatica.
Adult form
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Egg
operculum
C. Lifecycle and Epidemiology
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Fasciolopis buski infect both humans and pigs. After ingestion of the
metacercariae, excystation occurs in the duodenum and the organism attaches to
the wall of the small intestine where it resides. The adult form develops in about 3
months and produces unembryonated eggs, which are egested in the feces. The
adults have a life span of about one year. In the water, the eggs become
embryonated and release miracidia, which infect the intermediate host, the snail.
Within the snail, the miracidia develop into the sporocyst, rediae and cercariae
forms. Finally, the cercariae are released from the snail and rest on aquatic plant
life. Here, the cercariae undergo encystation to form the metacercariae, which are
ingested by the definitive host (pig or human). The pigs are considered the
reservoir host.
D. Geographic Distribution
Fasciolopis buski is found primarily in Asia, specifically in China, Taiwan,
Malaysia, and India. It is found especially in areas where humans raise pigs and
consume freshwater plants.
E. Pathology and Symptoms
Many cases are mild or asymptomatic, however, the symptoms of more severe
infections include abdominal pain, diarrhea, malabsorption, ulceration,
hemorrhaging and intestinal obstruction. Death can result in some individuals.
According to the CDC, Prevalence is approximately 1.9 million people infected
with Fasciolopis buski in China. Morbidity is much higher in children, with 57%
of children in China infected by Fasciolopis buski.
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F. Diagnosis
Diagnosis is done primarily through microscopic identification of eggs in stool
samples or vomitus; however, Fasciolopis buski eggs cannot be distinguished from
the eggs of Fasciola hepatica. Although the eggs cannot be differentiated, one can
determine the type of infection by the organs affected. F. hepatica infects the
liver, while F. buski infects the small intestine. Occasionally the adult form can be
identified in the samples as well.
G. Treatment of the individual
Patients are typically treated with praziquantel a drug, which is approved by the
FDA, but considered investigational for the treatment of parasites.
H. Eradication from the area
Methods of eradication include proper sanitation and sewage treatment. It is
advised that people avoiding eating uncooked aquatic plants such as water bamboo
and water chestnuts.
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Websites Used
Ohio State University College of Biological Sciences
http://www.biosci.ohio-state.edu/~parasite/fasciolopsis.html
http://link.springer.ny.com/link/service/journals/00436/bibs/1087001/10870
080.htm
Atlas of Medical Parasitology Carlo Denegri Foundation
http://www.cdfound.to.it/HTML/fas2.htm
Centers for Disease Control & Prevention, National Center for Infectious
Diseases, Division of Parasitic Diseases, Image Library
http://www.dpd.cdc.gov/dpdx/HTML/ImageLibrary/Fasciolopsiasis_il.asp?body=
A-F/Fasciolopsiasis/body_Fasciolopsiasis_il_th.htm
Centers for Disease Control & Prevention, National Center for Infectious
Diseases, Division of Parasitic Diseases, Parasites and Health.
http://www.dpd.cdc.gov/dpdx/HTML/Fasciolopsiasis.htm
CDC Emerging Infections Diseases Vol. 3 No.3 1997
http://www.cdc.gov/ncidod/eid/vol3no3/hotez.htm
DRUGS FOR PARASITIC INFECTIONS
The Medical Letter®On Drugs and Therapeutics
Published by The Medical Letter, Inc. • 1000 Main Street, New Rochelle, NY 10801
August 2004
http://www.medletter.com/freedocs/parasitic.pdf
University of Guelph, Canada
http://www.uoguelph.ca/~kkolas/fluke.html
Dendinger
Spring 2005
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