Diphyllobothrium Latum Karla Bennett May 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/ParaSites200 5/Diphyllobothriasis/New%20Folder/index.htm http://www.dpd.cdc.gov/dpdx/html/Frames/A- F/Diphyllobothriasis/body_Diphyllobothriasis_mic1.ht m 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.ht ml

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?