芽囊原虫属

芽囊原蟲属（学名：Blastocystis）包含一些单细胞不等鞭毛类的寄生虫，一般在各种动物的胃肠道内生活造成芽囊原蟲感染（blastocystosis），在人类、牲畜、鸟类、鼠类、爬行类、两栖类、蟑螂体内都有分布。此類生物对宿主选择性不高，因此有多个（分类学上的）物种都可感染人类；按现有医学分类习惯，这些物种都可称作人芽囊原虫（Blastocystis hominis）。芽囊原蟲属的分類地位曾多次變化，最初因外型與酵母菌相似、缺乏偽足以及不能移動等特色而被認為是一類酵母菌，後來一度被歸為原生生物（孢子蟲綱，今屬頂複門），1996年的分子種系發生學研究將其歸為不等鞭毛類的一員。 芽囊原蟲可感染人類而導致芽囊原蟲病（英语：Blastocystosis），此類生物感染人类甚多，在美国的感染率高达23%（2000年）。在发展中国家更高，尤其是塞內加爾河谷儿童全数受感染。此虫过去认为不致病（无症状感染者甚多），但二十一世纪起开始发现其可导致腹泻、疲劳等症状。流行病学观察认为此虫可能引发肠易激综合征。然而目前还缺乏对此虫致病性的决定性证据（健康人士感染后发病）。 此虫在人类中以粪口途径传播，主要是通过进食受粪便污染水、食物感染。离自来水厂够近，含氯充足的自来水不会导致感染。同一个家庭中的成人基本不会互相传播疾病，即使同居多年都还可能各自携带不同的芽囊原蟲。 Alexeieff A. Sur la nature des formations dites "kystes de Trichomonas intestinalis". CR Soc Biol. 1911, 71: 296–298.  Yoshikawa H, Wu Z, Howe J, Hashimoto T, Geok-Choo N, Tan KS. Ultrastructural and phylogenetic studies on Blastocystis isolates from cockroaches. The Journal of Eukaryotic Microbiology. 2007, 54 (1): 33–7. PMID 17300516. S2CID 45995362. doi:10.1111/j.1550-7408.2006.00141.x.  Noël C, Dufernez F, Gerbod D, et al. Molecular Phylogenies of Blastocystis Isolates from Different Hosts: Implications for Genetic Diversity, Identification of Species, and Zoonosis. Journal of Clinical Microbiology. January 2005, 43 (1): 348–55. PMC 540115 . PMID 15634993. doi:10.1128/JCM.43.1.348-355.2005 （中文）.  Brumpt E. Blastocystis hominis n. sp. et formes voisines. Bulletin of the Exotic Pathology Society. 1912, 5: 725–30.  Pérez-Cordón, Gregorio; Rosales, María J.; Gavira, María del Mar; Valdez, Renzo A.; Vargas, Franklin; Córdova, Ofelia. Finding of Blastocystis sp. in bivalves of the genus Donax. Revista Peruana de Biología. December 2007, 14 (2): 301–302. ISSN 1727-9933.  Stechmann A, Hamblin K, Pérez-Brocal V, et al. Organelles in Blastocystis that Blur the Distinction between Mitochondria and Hydrogenosomes. Current Biology. April 2008, 18 (8): 580–5. PMC 2428068 . PMID 18403202. doi:10.1016/j.cub.2008.03.037.  Silberman JD, Sogin ML, Leipe DD, Clark CG. Human parasite finds taxonomic home. Nature. 1996, 380 (6573): 398. Bibcode:1996Natur.380..398S. PMID 8602239. S2CID 4356573. doi:10.1038/380398a0 .  El Safadi D, Gaayeb L, Meloni D, Cian A, Poirier P, Wawrzyniak I, Delbac F, Dabboussi F, Delhaes L, Seck M, Hamze M, Riveau G, Viscogliosi E. Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide. BMC Infect. Dis. March 2014, 14: 164. PMC 3987649 . PMID 24666632. doi:10.1186/1471-2334-14-164.  Roberts T, Stark D, Harkness J, Ellis J. Update on the pathogenic potential and treatment options for Blastocystis sp. Gut Pathog. May 2014, 6: 17. PMC 4039988 . PMID 24883113. doi:10.1186/1757-4749-6-17. Blastocystis is one of the most common intestinal protists of humans. ... A recent study showed that 100% of people from low socio-economic villages in Senegal were infected with Blastocystis sp. suggesting that transmission was increased due to poor hygiene sanitation, close contact with domestic animals and livestock, and water supply directly from well and river [10]. ... Table 2: Summary of treatments and efficacy for Blastocystis infection  Amin OM. Seasonal prevalence of intestinal parasites in the United States during 2000 (PDF). Am. J. Trop. Med. Hyg. 2002, 66 (6): 799–803 [3 January 2016]. PMID 12224595. doi:10.4269/ajtmh.2002.66.799. （原始内容 (PDF)存档于27 May 2020）. Parasitologic investigations of large patient populations are rarely conducted in the United States, where the illusion of freedom from parasitic infections still predominates. Such investigations are considerably more common in third-world countries where endemic parasitoses are more readily documented.1 In an attempt to address this problem we reported the results of routine examination of fecal specimens for parasites from 644 patients in the United States during the summer of 1996. ... Prevalence. Nine hundred sixteen (32%) of 2,896 tested patients were infected with 18 species of intestinal parasites in the year 2000 (Table 1) in 48 states and the District of Columbia as follows ... Blastocystis hominis was the most frequently detected parasite in single and multiple infections, with Cryptosporidium parvum and Entamoeba histolytica/E. dispar ranking second and third, respectively.  Boorom KF, Smith H, Nimri L, Viscogliosi E, Spanakos G, Parkar U, Li LH, Zhou XN, Ok UZ, Leelayoova S, Jones MS. Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection. Parasit Vectors. 2008, 1 (1): 40. PMC 2627840 . PMID 18937874. doi:10.1186/1756-3305-1-40. Blastocystis is now by far the most prevalent mono-infection in symptomatic patients in the United States [14] and was found 28.5 times more often than Giardia lamblia as a mono-infection in symptomatic patients in a 2000 study [14]. Figure 4: Prevalence of IBS and Blastocystosis by country  Tan, K.S.W. Blastocystis in humans and animals: new insights using modern methodologies. Vet. Parasitol. 1986, 126 (1–2): 121–144. PMID 15567582. doi:10.1016/j.vetpar.2004.09.017.  Basualdo J, Pezzani B, De Luca M, Córdoba A, Apezteguía M. Screening of the municipal water system of La Plata, Argentina, for human intestinal parasites. Int J Hyg Environ Health. 2000, 203 (2): 177–82. PMID 11109572. doi:10.1078/S1438-4639(04)70025-5.  Kaneda Y, Horiki N, Cheng XJ, Fujita Y, Maruyama M, Tachibana H. Ribodemes of Blastocystis hominis isolated in Japan. Am. J. Trop. Med. Hyg. 2001, 65 (4): 393–6. PMID 11693890. doi:10.4269/ajtmh.2001.65.393 .