Английская Википедия:Entamoeba polecki
Шаблон:Short description Шаблон:Speciesbox
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]
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]
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
- 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
- ↑ Iran J Parasitol: Vol. 10, No. 2, Apr -Jun 2015, pp.146-156
- ↑ 2,0 2,1 2,2 2,3 2,4 2,5 2,6 Шаблон:Cite web
- ↑ 3,0 3,1 3,2 3,3 3,4 3,5 Шаблон:Cite book
- ↑ Шаблон:Cite book
- ↑ 5,0 5,1 5,2 5,3 5,4 5,5 Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ 8,0 8,1 8,2 Шаблон:Cite book
