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Diphyllobothriasis is an infection usually caused by the tapeworm Diphyllobothrium latum. The condition may be caused by other Diphyllobothrium species too.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Fish Tapeworm Infection
  • Intestinal Diphyllobothriasis
  • Jewish Housewife’s Disease

What is Diphyllobothriasis? (Definition/Background Information)

  • Diphyllobothriasis is an infection usually caused by the tapeworm Diphyllobothrium latum. The condition may be caused by other Diphyllobothrium species too
  • These parasites are flatworms that infect the intestinal tract of human beings. Individuals are affected by eating raw or uncooked freshwater fish that contain tapeworm cysts. Some saltwater fishes may also harbor this organism
  • Diphyllobothriasis may cause abdominal pain, appetite loss, diarrhea or constipation, vomiting, nausea, and fatigue. The condition may be diagnosed by examining the stool samples
  • The treatment involves the administration of oral and intravenous medications. The prognosis is generally good with no significant long-term complications, if the condition is suitably treated

Who gets Diphyllobothriasis? (Age and Sex Distribution)

  • All individuals, having a regular habit of taking raw or undercooked fish, are likely to get Diphyllobothriasis. Individuals of all ages may be affected by the infection
  • Jewish women were once most commonly infected by the parasite, due to their tradition of tasting fish, before it was fully-cooked. For this reason, Diphyllobothriasis is also known as “Jewish Housewife’s Disease”
  • Otherwise, no specific ethnic or racial predilection is noted

What are the Risk Factors for Diphyllobothriasis? (Predisposing Factors)

The risk factors for Diphyllobothriasis include:

  • Consumption of raw or undercooked (usually) freshwater fish
  • Fishermen and their families, who primarily consume fish are higher prone to the condition
  • Housewives are at a high risk, when they taste undercooked fish, during its preparation
  • Eating certain regional cuisines, where raw/semi-cooked fish  is served; like in certain Japanese, French, or Italian food preparations
  • People living in areas where eating freshwater fish (including dry-salted, smoked) is common, like in Eastern Europe, North and South Americas, some African, Asian, and Scandinavian countries

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Diphyllobothriasis? (Etiology)

  • Humans are infected by Diphyllobothriasis, when they eat raw or undercooked fish that contains fish tapeworm cysts (especially belonging to the tapeworm Diphyllobothrium latum)
  • When an individual consumes the infected fish, the tapeworm larva begins to grow in the intestine. In about 3-6 weeks’ time, it grows to become an adult worm
  • Eggs are formed in each segment of the worm, which is then passed out in the stool. Sometimes, the whole worm or parts of the worm may be seen in the stool

What are the Signs and Symptoms of Diphyllobothriasis?

The following signs and symptoms characterize a Diphyllobothriasis infection:

  • Abdominal pain
  • Loss of appetite, sudden weight loss
  • Diarrhea or constipation
  • Vomiting, nausea, and fatigue
  • Deficiency of vitamin B12
  • Anemia
  • Presence of worm eggs (or worm parts) in stool
  • In most of the human population, the infection remains asymptomatic

How is Diphyllobothriasis Diagnosed?

A diagnosis of Diphyllobothriasis may involve:

  • Physical evaluation and study of medical history
  • Examination of stool for the presence of eggs and parasites; tapeworm segments (proglottids) passed in the stool, is also examined for confirmation
  • Complete blood count to check for anemia

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Diphyllobothriasis?

The possible complications that can arise from Diphyllobothriasis are:

  • Vitamin B12 deficiency leading to megaloblastic anemia (blood disorder characterized by anemia with larger than normal-sized red blood cells)
  • Intestinal obstruction in extreme infections

How is Diphyllobothriasis Treated?

The treatment measures for Diphyllobothriasis mainly involve:

  • Taking oral medications like praziquantel or niclosamide. The healthcare provider will choose the specific medications necessary, since some of the medications are not (US FDA) approved
  • Vitamin B12 injections are taken as supplements, in order to treat megaloblastic anemia

How can Diphyllobothriasis be Prevented?

The following preventive measures can be adopted to reduce the risk of Diphyllobothriasis:

  • Eating raw or undercooked (especially freshwater) fish must be avoided. Cooking fish to temperatures over 145 deg. F (63 deg. C) kills the parasitic organism
  • Wash hands properly after cleaning fish, before preparing food, and before eating
  • Freshwater fish may be stored frozen before preparation; freezing fish up to -4 deg. F (-20 deg. C) for 24 hours, helps kill the tapeworm eggs
  • Proper disposal of sewage (including fish wastes) can help bring down the risk of contracting Diphyllobothriasis
  • Proper hygiene must be adhered to at all times (by both children and adults) - wash hands with soap and water after defecation
  • Water contaminated or infected with feces (containing the parasite) must be avoided

What is the Prognosis of Diphyllobothriasis? (Outcomes/Resolutions)

  • In most cases, a single dose of drugs is enough to treat Diphyllobothriasis
  • The parasitic infection generally does not leave any long-lasting effects

Additional and Relevant Useful Information for Diphyllobothriasis:

The following DoveMed website link is a useful resource for additional information:


What are some Useful Resources for Additional Information?

Centers for Disease Control and Prevention (CDC)
1600 Clifton Rd. Atlanta, GA 30333, USA
Phone: (404) 639-3534
Toll-Free: 800-CDC-INFO (800-232-4636)
TTY: (888) 232-6348
Email: cdcinfo@cdc.gov
Website: http://www.cdc.gov

References and Information Sources used for the Article:

http://www.fda.gov/food/foodsafety/foodborneillness/foodborneillnessfoodbornepathogensnaturaltoxins/badbugbook/ucm070785.htm (accessed on 05/18/2014)

http://www.umm.edu/ency/article/001375.htm (accessed on 05/18/2014)

http://www.ehow.com/about_5367279_life-cycle-diphyllobothrium-latum.html (accessed on 05/18/2014)

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002351/ (accessed on 05/18/2014)

http://www.parasitesinhumans.org/diphyllobothrium-latum-fish-tapeworm.html (accessed on 05/18/2014)

Helpful Peer-Reviewed Medical Articles:

Dupouy-Camet, J., & Peduzzi, R. (2004). Current situation of human diphyllobothriasis in Europe. Euro Surveill, 9(5), 31-35.

Scholz, T., Garcia, H. H., Kuchta, R., & Wicht, B. (2009). Update on the human broad tapeworm (genus diphyllobothrium), including clinical relevance. Clin Microbiol Rev, 22(1), 146-160, Table of Contents. doi: 10.1128/CMR.00033-08

Fang, F. C., Billman, Z. P., Wallis, C. K., Abbott, A. N., Olson, J. C., Dhanireddy, S., & Murphy, S. C. (2015). Human Diphyllobothrium nihonkaiense Infection in Washington State. Journal of clinical microbiology, 53(4), 1355-1357.

Wiwanitkit, S., & Wiwanitkit, V. (2016). Journal of Coastal Life Medicine. Journal of Coastal Life Medicine, 4(1), 78-79.

Go, Y. B., Lee, E. H., Cho, J., Choi, S., & Chai, J. Y. (2015). Diphyllobothrium nihonkaiense Infections in a Family. The Korean journal of parasitology, 53(1), 109.

Lee, S. H., Park, H., & Yu, S. T. (2015). Diphyllobothrium latum infection in a child with recurrent abdominal pain. Korean journal of pediatrics, 58(11), 451-453.

Dick, T. A., Nelson, P. A., & Choudhury, A. (2001). Diphyllobothriasis: update on human cases, foci, patterns and sources of human infections and future considerations. Southeast Asian journal of tropical medicine and public health, 32, 59-76.

Reinhard, K., & Urban, O. (2003). Diagnosing ancient diphyllobothriasis from Chinchorro mummies. Memórias do Instituto Oswaldo Cruz, 98, 191-193.