Taenia infection

Revision as of 00:08, 18 January 2009 by Zorkun (talk | contribs)
Jump to navigation Jump to search
Taenia infection
File:Image:Taenia egg.jpg
Taenia egg

WikiDoc Resources for Taenia infection

Articles

Most recent articles on Taenia infection

Most cited articles on Taenia infection

Review articles on Taenia infection

Articles on Taenia infection in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Taenia infection

Images of Taenia infection

Photos of Taenia infection

Podcasts & MP3s on Taenia infection

Videos on Taenia infection

Evidence Based Medicine

Cochrane Collaboration on Taenia infection

Bandolier on Taenia infection

TRIP on Taenia infection

Clinical Trials

Ongoing Trials on Taenia infection at Clinical Trials.gov

Trial results on Taenia infection

Clinical Trials on Taenia infection at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Taenia infection

NICE Guidance on Taenia infection

NHS PRODIGY Guidance

FDA on Taenia infection

CDC on Taenia infection

Books

Books on Taenia infection

News

Taenia infection in the news

Be alerted to news on Taenia infection

News trends on Taenia infection

Commentary

Blogs on Taenia infection

Definitions

Definitions of Taenia infection

Patient Resources / Community

Patient resources on Taenia infection

Discussion groups on Taenia infection

Patient Handouts on Taenia infection

Directions to Hospitals Treating Taenia infection

Risk calculators and risk factors for Taenia infection

Healthcare Provider Resources

Symptoms of Taenia infection

Causes & Risk Factors for Taenia infection

Diagnostic studies for Taenia infection

Treatment of Taenia infection

Continuing Medical Education (CME)

CME Programs on Taenia infection

International

Taenia infection en Espanol

Taenia infection en Francais

Business

Taenia infection in the Marketplace

Patents on Taenia infection

Experimental / Informatics

List of terms related to Taenia infection

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Overview

Also known as: Tapeworm infection

References

http://www.cdc.gov/ncidod/diseases/index_qz.htm#t

http://www.cdc.gov/ncidod/dpd/parasites/taenia/default.htm

Epidemiology and Demographics

Both species are worldwide in distribution. Taenia solium is more prevalent in poorer communities where humans live in close contact with pigs and eat undercooked pork, and is very rare in Muslim countries.

References

http://www.dpd.cdc.gov/dpdx/HTML/Taeniasis.htm

Pathophysiology & Etiology

The cestodes (tapeworms) Taenia saginata (beef tapeworm) and T. solium (pork tapeworm). Taenia solium can also cause cysticercosis.

Life cycle of Taenia saginata and T. solium


Taeniasis is the infection of humans with the adult tapeworm of Taenia saginata or Taenia solium. Humans are the only definitive hosts for T. saginata and T. solium. Eggs or gravid proglottids are passed with feces 1 ; the eggs can survive for days to months in the environment. Cattle (T. saginata) and pigs (T. solium) become infected by ingesting vegetation contaminated with eggs or gravid proglottids 2 . In the animal's intestine, the oncospheres hatch 3 , invade the intestinal wall, and migrate to the striated muscles, where they develop into cysticerci. A cysticercus can survive for several years in the animal. Humans become infected by ingesting raw or undercooked infected meat 4 . In the human intestine, the cysticercus develops over 2 months into an adult tapeworm, which can survive for years. The adult tapeworms attach to the small intestine by their scolex 5 and reside in the small intestine 6 . Length of adult worms is usually 5 m or less for T. saginata (however it may reach up to 25 m) and 2 to 7 m for T. solium. The adults produce proglottids which mature, become gravid, detach from the tapeworm, and migrate to the anus or are passed in the stool (approximately 6 per day). T. saginata adults usually have 1,000 to 2,000 proglottids, while T. solium adults have an average of 1,000 proglottids. The eggs contained in the gravid proglottids are released after the proglottids are passed with the feces. T. saginata may produce up to 100,000 and T. solium may produce 50,000 eggs per proglottid respectively.

References

http://www.dpd.cdc.gov/dpdx/HTML/Taeniasis.htm

History and Symptoms

Taenia saginata taeniasis produces only mild abdominal symptoms. The most striking feature consists of the passage (active and passive) of proglottids. Occasionally, appendicitis or cholangitis can result from migrating proglottids. Taenia solium taeniasis is less frequently symptomatic than Taenia saginata taeniasis. The main symptom is often the passage (passive) of proglottids. The most important feature of Taenia solium taeniasis is the risk of development of cysticercosis.

References

http://www.dpd.cdc.gov/dpdx/HTML/Taeniasis.htm

Laboratory Findings

Microscopic identification of eggs and proglottids in feces is diagnostic for taeniasis, but is not possible during the first 3 months following infection, prior to development of adult tapeworms. Repeated examination and concentration techniques will increase the likelihood of detecting light infections. Nevertheless, speciation of Taenia is impossible if solely based on microscopic examination of eggs, because all Taenia species produce eggs that are morphologically identical. Eggs of Taenia sp. are also indistinguishable from those produced by cestodes of the genus Echinococcus (tapeworms of dogs and other canid hosts). Microscopic identification of gravid proglottids (or, more rarely, examination of the scolex) allows species determination.

Taenia egg
Taenia egg


A, B: Taeniid eggs. The eggs of Taenia saginata and Taenia solium are indistinguishable morphologically (morphologic species identification will have to rely on the proglottids or scolices). The eggs are rounded, diameter 31 to 43 µm, with a thick radially striated brown shell. Inside each shell is an embryonated oncosphere with 6 hooks. The egg in Figure B still has the primary membrane that surrounds eggs in the proglottids.

Pollen artifact
Pollen artifact


C: Pollen artifact that could be mistaken for a taeniid egg; however, the shell is thinner, of nonuniform thickness, and no hooks are visible.

Taenia saginata gravid proglottid
Taenia saginata gravid proglottid


Taenia solium gravid proglottid
Taenia solium gravid proglottid


D, E, F, G: Gravid proglottids of Taenia saginata (Figures D and E) and Taenia solium (Figures F and G). Injection of India ink in the uterus allows visualization of the primary lateral branches. Their number allows differentiation between the two species: T. saginata has 15 to 20 branches on each side (Figure D and E), while Taenia solium has 7 to 13 (Figures F and G). Note the genital pores in mid-lateral position.

References

http://www.dpd.cdc.gov/dpdx/HTML/Taeniasis.htm

Treatment

Pharmacotherapy

Treatment is simple and very effective. Praziquantel is the drug of choice (This drug is approved by the FDA, but considered investigational for this purpose).

References

http://www.dpd.cdc.gov/dpdx/HTML/Taeniasis.htm

Acknowledgements

The content on this page was first contributed by: C. Michael Gibson, M.S., M.D.


Template:SIB


Template:WH Template:WikiDoc Sources