Entamoeba polecki

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Entamoeba polecki
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Phylum: Amoebozoa
Family: Entamoebidae
Genus: Entamoeba
Species:
E. polecki
Binomial name
Entamoeba polecki
von Prowazek, 1912

Entamoeba polecki is an intestinal parasite [1] of the genus Entamoeba . E. polecki is found primarily in pigs and monkeys and is largely considered non-pathogenic in humans, although there have been some reports regarding symptomatic infections of humans. [2] Prevalence is concentrated in New Guinea, with distribution also recorded in areas of southeast Asia, France, and the United States. [3]

Contents

Morphology

Mature trophozoites of E. polecki are generally 10-20 μm in diameter. Trophozoites are irregularly shaped and possess pseudopodia for motility. [3] They have a single nucleus with a small central karyosome and finely dispersed peripheral chromatin, similar to that of Entamoeba histolytica [3] . Cytoplasmic contents are similar to other Entamoeba sp. and are usually granular and vacuolated. [3] Cysts of E. polecki are morphologically unique, containing only one nucleus, varyingly sized chromatoid bars, and a large inclusion mass. [3] [4]

Life cycle of Entamoeba sp. Common Non-pathogen Parasites Lifecycle.png
Life cycle of Entamoeba sp.

Transmission & life cycle

There are two stages in the life cycle of E. polecki. [2] The first is as a trophozoite, a vegetative stage that cannot survive in the environment. [2] The second is a cyst, where transmission of parasite is possible and provides protection to harsh external environments. Cysts are infective when ingested by another organism. [2] The cystic form of this protozoan has a diameter as small as 9.5 μm and as large as 17.5 μm. Morphologically, E. polecki is extremely similar to Entamoeba histolytica and Entamoeba hartmanni. [2]

Transmission follows a fecal-oral route. Infected feces with mature cysts are ingested where the cyst matures to the trophozoite in the gastrointestinal tract of the host. It is considered to be a zoonotic parasite, as close contact with infected swine have been reported to be the cause of E. polecki infections in humans. [5] Transmission to humans from consumption of pork is unlikely. [6] Recent studies suggest that different subspecies infect non-human primates and pigs, and close inhabitation between the two do not coincide with transmission. [7]

Pathology

Entamoeba polecki is considered to be non-pathogenic in humans. Nonspecific symptoms from infection have been reported, including nausea, vomiting, diarrhea, bloody stools, and fever. [8] [5] Prevalence of infection amongst swine may be up to 25% across the world, but tend to be asymptomatic. [5]

Diagnosis and treatment

Examination of stool samples for uninucleated cysts and trophozoites have been used for diagnosis. [8] This method is not always reliable due to morphological similarities between E. polecki and other Entamoeba species. [8] [5] More recent diagnostic methods utilizing DNA amplification and comparison have been used to better differentiate amongst pathogenic and species such as E. histolytica and non-pathogenic species. [5] A definitive diagnosis can be made by using electroimmunotransfer blots. [2] Serological testing is not accurate between species of Entamoeba. [2]

Treatment of infection is similar to that of other Entamoeba infections. Anti-parasitic medications such as metronidazole and ornidazole are generally used to treat human infections. [3] Combination therapies such as metronidazole and diloxanide furoate have been effective as well. [5]

References

  1. ↑ Iran J Parasitol: Vol. 10, No. 2, Apr -Jun 2015, pp.146-156
  2. 1 2 3 4 5 6 7 "Entamoeba Polecki". web.stanford.edu. Retrieved 2018-03-24.
  3. 1 2 3 4 5 6 A., Gockel-Blessing, Elizabeth (2013). Clinical parasitology : a practical approach (2nd ed.). St. Louis, Mo.: Elsevier Saunders. ISBN   9781416060444. OCLC   816557145.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. ↑ Roberts, Larry S. (2005). Gerald D. Schmidt & Larry S. Roberts' foundations of parasitology. Janovy, John, Jr., 1937- (7th ed.). Boston: McGraw-Hill. ISBN   978-0072348989. OCLC   54400427.
  5. 1 2 3 4 5 6 Solaymani-Mohammadi, S.; Petri, W.A. (2006). "Zoonotic implications of the swine-transmitted protozoal infections". Veterinary Parasitology. 140 (3–4): 189–203. doi:10.1016/j.vetpar.2006.05.012. PMID   16828229.
  6. ↑ Djurković-Djaković, O.; Bobić, B.; Nikolić, A.; Klun, I.; Dupouy-Camet, J. (2013). "Pork as a source of human parasitic infection". Clinical Microbiology and Infection. 19 (7): 586–594. doi: 10.1111/1469-0691.12162 . PMID   23402388.
  7. ↑ Tuda, Josef; Feng, Meng; Imada, Mihoko; Kobayashi, Seiki; Cheng, Xunjia; Tachibana, Hiroshi (2016-09-01). "Identification ofEntamoeba poleckiwith Unique 18S rRNA Gene Sequences from Celebes Crested Macaques and Pigs in Tangkoko Nature Reserve, North Sulawesi, Indonesia". Journal of Eukaryotic Microbiology. 63 (5): 572–577. doi:10.1111/jeu.12304. ISSN   1550-7408. PMID   26861809. S2CID   5211949.
  8. 1 2 3 J., Magill, Alan (2012). Hunter's tropical medicine and emerging infectious disease. Strickland, G. Thomas., Maguire, James H., Ryan, Edward T., Solomon, Tom. (9th ed.). London: Elsevier Health Sciences. ISBN   9781416043904. OCLC   861539914.{{cite book}}: CS1 maint: multiple names: authors list (link)
  1. Cook R. Entamoeba Polecki [Internet]. Web.stanford.edu. 2004 [cited 23 March 2018]. Available from: https://web.stanford.edu/group/parasites/ParaSites2004/Entamoeba/Entamoeba%20Polecki.htm
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