Diphyllobothrium Latum

Karla BennettMay 2012

General Information

•It is known as the “fish tapeworm”•Diphyllobothrium latum is a cestode (a

hermaphrodiditic worm that is a parasite of the vertebrate intestinal tract).

Terminology

•Plerocercoid-the larval form. Also the infective stage found in the raw flesh of freshwater fishes.

•D. latum- the adult worm•Proglottids- the segments of the flat

worm. Each contains both male and female reproductive organs

•Scolex- the part on the anterior end that is long and spoon-shaped. It is what the worm uses to attach itself to the intestinal tract.

History of Diphyllobothriasis

•Its distribution is worldwide•It occurs where pickled or insufficiently

cooked fish are part of the cultural diet. (Northern temperate areas)

Hosts and Intermediates

•Intermediates: Freshwater fish and copepods

•Definitive host: Humans and other vertebrates.

Life Cycle

Symptoms

•constipation•diarrhea• fatigue•obstruction of the bowel•pernicious anemia (caused by vitamin B12

deficiency) which can lead to subacute combined degeneration of spinal cord

•stomach pain•vomiting•weight loss.

Diagnosis and Treatment

•Examination of a fecal sample for eggs and proglottoids is the quickest way to diagnose Diphyllobothriasis.

•All diphyllobothrium species respond to the same treatment.

•The best method is a diatrizoic acid injection into the duodenal wall.

•Praziquantel or niclosamide are not as effective because they do not remove the attached head from the intestine wall.

Prevention

•Cook fish properly. If you eat sashimi or sushi, freeze it first at -10 °C (or below) for two days to kill the tapeworm larvae.

•Do not defecate in water. If the fish tapeworm larvae cannot get in touch with the intermediate hosts, they cannot infect humans.

Citation

• http://www.parasitesinhumans.org/diphyllobothrium-latum-fish-tapeworm.html

• http://www.stanford.edu/group/parasites/ParaSites2005/Diphyllobothriasis/New%20Folder/index.htm

• http://www.dpd.cdc.gov/dpdx/html/Frames/A-F/Diphyllobothriasis/body_Diphyllobothriasis_mic1.htm

• http://www.human-healths.com/wp-content/uploads/2011/08/Diphyllobothrium2.gif

• http://www.kmle.co.kr/search.php?Search=latum

• http://www.ifood.tv/network/pickled_herring

• http://www.realmonstrosities.com/2011/02/copepod.html

TRIVIA!

•Name 3 symptoms of Diphyllobothriasis.•What is the name of the best drug for

treatment and why is it better than the others?

•Name the two intermediate hosts in the lifecycle.

•What is the name of the anatomical body part of the parasite that it uses to attach itself to the intestine?

•Why does the entire adult worm need to be removed?