Diphyllobothrium dendriticum

Diphyllobothrium dendriticum is a large pseudophyllid cestode of the family Diphyllobothriidae.[1]

This article is about the tapeworm. For the infection by adult worms, see Diphyllobothriasis.

Diphyllobothrium dendriticum
Median segments of Diphyllobothrium dendriticum
Scientific classification
Kingdom:
Animalia
Phylum:
Platyhelminthes
Class:
Cestoda
Subclass:
Eucestoda
Order:
Pseudophyllidea
Family:
Diphyllobothriidae
Genus:
Diphyllobothrium

Cobbold, 1858
Species:
D. dendriticum
Binomial name
Diphyllobothrium dendriticum

For many years D. dendriticum infection was neglected.[1] Diphyllobothriasis is not a life-threatening disease and most human cases are mild or even asymptomatic. The original distribution of D. dendriticum is circumboreal, but it was also found in Argentina and Chile.[2][3]

Life cycle
Life cycle of D. latum. Click the image to see full-size.

The life cycle of D. dendriticum is similar to life cycles of other Diphyllobothrium species, all of which include three hosts. Freshwater copepods serve as the first intermediate hosts; fish serve as the second intermediate hosts. Moreover, many predator fish species can be paratenic hosts for Diphyllobothriidae, i.e., accumulate plerocercoids (the larval stage that infects definitive hosts) in muscles and internal organs.[4]

Eggs are passed unembryonated in feces. Under appropriate conditions, the eggs mature and yield oncosphere which develop into a coracidia.[5] Planktonic copepods serve as the first intermediate hosts in which the larval stage, called procercoid develops. The second larval stage or metacestode, called plerocercoid, develops in second intermediate host, freshwater and anadromous fishes, especially salmonids.[1] Because humans do not generally eat these small fish species raw, the second intermediate host probably does not represent an important source of human infection. However, these small second intermediate hosts can be eaten by larger predator species that then serve as paratenic host. Plerocercoid larvae is the infectious stage for the definitive host.[5] Plerocercoids of D. dendriticum are usually encysted within the visceral organs or body cavity. Humans can become infected either by consuming raw or undercooked visceral organs, such as liver and ovaries.

See also
  • List of parasites (human)

References
  1. Kuchta, Roman; Brabec, Jan; Kubáčková, Petra; Scholz, Tomáš (2013-12-26). "Tapeworm Diphyllobothrium dendriticum (Cestoda)—Neglected or Emerging Human Parasite?". PLoS Neglected Tropical Diseases. 7 (12). doi:10.1371/journal.pntd.0002535. ISSN 1935-2727. PMC 3873255. PMID 24386497. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  2. Rozas, M.; Bohle, H.; Sandoval, A.; Ildefonso, R.; Navarrete, A.; Bustos, P. (December 2012). "First molecular identification of Diphyllobothrium dendriticum plerocercoids from feral rainbow trout (Oncorhynchus mykiss) in Chile". The Journal of Parasitology. 98 (6): 1220–1226. doi:10.1645/JP-GE-3097.1. ISSN 1937-2345. PMID 22715967.
  3. Torres, P.; Franjola, R.; Figueroa, L.; Schlatter, R.; González, H.; Contreras, B.; Martin, R. (September 1981). "Researches on Pseudophyllidea (Carus, 1813) in the south of Chile. IV Occurrence of Diphyllobothrium dendriticum (Nitzch)". Journal of Helminthology. 55 (3): 173–187. ISSN 0022-149X. PMID 7276504.
  4. Kuklina, M. M.; Kuklin, V. V. (July 2016). "Diphyllobothrium dendriticum (Cestoda: Diphyllobothriidae) in the intestinal tract of the herring gull Larus argentatus: Localization and trophic parameters". Biology Bulletin. 43 (4): 329–334. doi:10.1134/s1062359016040063. ISSN 1062-3590.
  5. Prevention, CDC-Centers for Disease Control and (2019-05-14). "CDC - Diphyllobothrium - Biology". www.cdc.gov. Retrieved 2020-12-19.
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