恙蟎目（Trombidiformes），亦作絨蟎目，是一個數量龐大而且分散的一個目，屬於蛛形綱蜱蟎亞綱蟎形總目之下，其幼蟲英文稱為chigger。
恙蟎生活史複雜，可分為七個時期：卵，次卵，幼蟎，前若蟎，次若蟎，三若蟎，成蟎。幼蟎為寄生性，次若蟎與成蟎為自由生活。以地里恙蟎（Leptotrombidium deliense）為例，這個物種從卵到成蟎的時間為58-76天[2]所以恙螨只有幼蟲為寄生性，若蟲及成蟲可自由生活；蟲卵孵化而成的幼蟲體長約0.2-0.3公釐，能吸附在爬蟲類、鳥類及哺乳類動物身上，溶解組織做為食物。吃飽後會離開宿主，蛻皮形成若蟲，並再次蛻皮成為成蟲。
最為人所知的是幼蟲為立克次體性疾病/恙蟲病的病媒。過去曾在日本大型河川的沙洲或兩岸地區流行的典型恙蟲病就是由赤蟲恙螨所引起的；由於經常在夏季發生，且致死率高，是一種十分恐怖的疾病。而致死率低的恙蟲病則是由粗毛恙螨或小盾恙螨等恙螨為病媒。典型恙蟲病或新型恙蟲病在確診後均有適當的抗生素可治療。
由於恙螨中帶有立克次體的個體，也有不帶有立克次體的個體，因此過去的人認為這些是由患有恙蟲病的老鼠，將立克次體傳染給恙螨後，恙螨的成蟲再將立克次體移行到蟲卵，蟲卵孵化後的幼蟲就會帶有立克次體，然後感染老鼠或人類。不過，後來發現，在患有恙蟲病的老鼠身上，即使人工寄生未帶有立克次體的幼蟲，立克次體也不會移行到恙螨之後，現在已經認為立克次體應該是恙螨的共生體[3]。
根據2004年時的分類，本目包括有125個科，超過2.2萬個品種[4]；在2011年的最新資料，本目現時包括有151個科，2235個屬及25,821個物種，另外還有10個屬24個物種是化石種[1]。這151個科可以大致分為以下四個亞目[1]：
- 跳螨亚目 Sphaerolichida OConnor, 1984：下領兩個總科
- 前气门亚目（Prostigmata Kramer, 1877）：本目最龐大的分支，下領四個下目、40個總科。
- 内气门亚目 Endeostigmata Reuter, 1909：下領五個總科、十個科、27個屬和108個物種，包括一些原屬疥蟎亞目但在甲蟎亞目及無氣門小目以外的物種。
- 甲蟎亞目（Oribatida van der Hammen, 1968）[5]：又名隱氣門亞目（Cryptostigmata），下領五個下目[6][7][8][9]，舊屬疥蟎目（Sarcoptiformes）[5]。
本目包括以下科：
- Acalyptonotidae
- Acarophenacidae
- Achaemenothrombiidae
- Acherontacaridae
- Acucapitidae
- Adamystidae
- Allochaetophoridae
- Allotanaupodidae
- Amoenacaridae
- Amoenacarus Smith & Cook, 1997
- Amoenacarus dixiensis [10]
- Amphotrombiidae
- Amphotrombium Zhang, 1998
- Anisitsiellidae
- Anystidae
- Apheviderulicidae
- Arenohydracaridae
- Arrenuridae
- Astacocrotonidae
- Athienemannidae
- Athienemanniidae
- Africasia K.Viets, 1931
- Anamundamella Cook, 1992
- Athienemannia Viets, 1920
- Bleptomundamella Cook, 2001
- Chelohydracarus Smith, 1998
- Chelohydracarus navarrensis[11]
- Chelomideopsis Romijn, 1920
- Davecookia Harvey, 2003
- Janszoonia Smit, 2007
- Mellamunda Harvey, 1988
- Mundamella Viets, 1913
- Notomundamella Cook, 1986
- Penemundamella Cook, 2001
- Phreatohydracarus Tanasachi & Orghidan, 1955
- Platyhydracarus Smith, 1989
- Plaumannia Lundblad, 1936
- Stygameracarus Smith, 1990
- Stygohydracarus K.H.Viets, 1932
- Athyreacaridae
- Aturidae
- Audyanidae
- Axonopsidae
- Bandakiopsidae
- Barbutiidae
- Bdellidae
- Bdella Latreille, 1795
- Bdellodes Oudemans, 1937
- Biscirus Thor, 1913
- Biscuris
- Caenobdella Oudemans, 1936
- Cyta von Heyden
- Hexabdella Van
- Hexabdella Van der Schyff, Theron & Ueckermann, 2004
- Hexabdella brevitarsus Hernandes, 2012
- Hexabdella cinquaginta Hernandes, Daud & Feres, 2007
- Hexabdella denheyeri Van der Schyff, Theron & Ueckermann, 2004
- Hexabdella maraugia Van der Schyff, Theron & Ueckermann, 2004
- Hexabdella mexicana (Baker & Balock, 1944)
- Hexabdella miranda Van der Schyff, Theron & Ueckermann, 2004
- Hexabdella persiaensis Paktinat Saeej & Bagheri, 2014[12]
- Hexabdella quercusi Eghbalian, Khanjani, Safaralizadeh & Ueckermann
- Hexabdella singula Van der Schyff, Theron & Ueckermann, 2004
- Hexabdella unusoculata Van der Schyff, Theron & Ueckermann, 2004
- Hoplomolgus Berlese
- Molgus Dujardin, 1842
- Monotrichobdella Baker & Balock, 1944
- Neobiscirus Gomelauri, 1963
- Neomolgus Oudemans, 1937
- Octobdellodes Atyeo, 1960
- Odontoscirus Thor, 1913
- Polytrichus van Der Schyff, Theron & Ueckermann
- Rigibdella Tseng, 1978
- Spinibdella Thor, 1930
- Tetrabdella Hernandes & Feres, 2006
- Trachymolgus Berlese, 1924
- Troglobdella Oudemans, 1938
- Bogatiidae
- Caeculidae
- Caligonellidae
- Calyptostomatidae
- Camerobiidae
- Caraboacaridae
- Chappuisididae
- Cheyletidae
- Cheyletiellidae
- Chulacaridae
- Chyzeriidae
- Cloacaridae
- Cocceupodidae
- Crotalomorphidae
- Cryptognathidae
- Cryptognathiidae
- Ctenothyadidae
- Cunaxidae
- Dasythyreidae
- Demodecidae
- Dendrochaetidae
- Diptilomiopidae
- Dolichocybidae
- Edbakerellidae
- Epimyodicidae
- Ereynetidae
- Eriophyidae
- Eriorhynchidae
- Erythracaridae
- 赤螨科 Erythraeidae
- Eupalopsellidae
- Eupalopsellus Sellnick, 1949
- Eupalopsis Canestrini, 1886
- Exothorhis Summers, 1960
- Peltasellus Smith-Meyer & Ueckermann, 1984
- Saniosulus Summers, 1960
- Eupodidae
- Aethosolenia Baker & Lindquist, 2002
- Benoinyssus Fain, 1958
- Caleupodes Baker, 1987
- Claveupodes Strandtmann & Prasse, 1976
- Cocceupodes Thor, 1934
- Eupodes Koch, 1835
- Hawaiieupodes Strandtmann & Goff, 1978
- Hylotydeus Berlese, 1891
- Linopodes C.L.Koch, 1835
- Neoprotereunetes Fain & Camerik, 1994
- Niveupodes Barilo, 1991
- Palaeotydeus Dubinin, 1962
- Protacarus Hirst, 1923
- Protereunetes Berlese, 1923
- Pseudoeupodes Khaustov, 2014
- Pseudoprotacarus Dubinin, 1962
- Eutrombidiidae
- Eylaidae
- Feltridae
- Feltriidae
- Ferradasiidae
- Frontipodopsidae
- Gretacaridae
- Halacaridae
- Harpagopalpidae
- Harpirhynchidae
- Harpyrhynchidae
- Heterocheyletidae
- Heterocheylidae
- Homocaligidae
- Hungarohydracaridae
- Hydrachnidae
- Hydrodromidae
- Hydrovolziidae
- Hydryphantidae
- Hygrobatidae
- Iolinidae
- Johnstonianidae
- Kantacaridae
- Krendowskiidae
- Labidostommatidae
- Labidostommidae
- Laversiidae
- Lebertiidae
- Leeuwenhoekiidae
- Lethaxonidae
- Limnesiidae
- Limnocharidae
- Linotetranidae
- Lordalycidae
- Malgasacaridae
- Mecognathidae
- Meyerellidae
- Microdispidae
- Microtrombidiidae
- Mideidae
- Mideopsidae
- Momoniidae
- 肉螨科 Myobiidae
- Nasutiacaridae
- Neoacaridae
- Neopygmephoridae
- Neothrombiidae
- Neotrombidiidae
- Nipponacaridae
- Nudomideopsidae
- Omartacaridae
- Oxidae
- Paratydeidae
- Hexatydeus Soliman, 1974
- Paratydeus Baker, 1949
- Scolotydaeus Berlese, 1910
- Scolotydaeus alexanderi (Baker, 1949) Khaustov, 2017
- Scolotydaeus anatolicus[13]
- Scolotydaeus lootsi (Theron et al., 1969) Khaustov, 2017
- Scolotydaeus tauricus (Kuznetsov, 1973) Khaustov, 2017
- Scolotydaeus uralensis Khaustov, 2017
- Scolotydeus Berlese, 1910
- Tanytydeus Theron, Meyer & Ryke, 1970
- Pentapalpidae
- Penthaleidae
- Penthalodidae
- Pezidae
- Phytoptidae
- Piersigiidae
- Pionidae
- Podapolipidae
- Archipolipus Husband, 1971
- Bakerpolipus Husband & Sinha, 1970
- Blaberpolipus Husband & OConnor, 2003
- Buprestapolipus Husband, Ochoa & Naskrecki, 1995
- Cassidopolipus Husband & OConnor, 2014
- Chrysomelobia Regenfuss, 1968
- Coccipolipus Husband, 1972
- Coccipolipus hippodamiae (McDaniel & Moril, 1969)[14]
- Coccipolipus macfarlanei Husband, 1972
- Curculapolipus Husband & Kurosa, 2000
- Cydnipolipus Kurosa & Husband, 1994
- Dilopolipus Husband, 1984
- Dorsipes Regenfuss, 1968
- Eutarsopolipus Berlese, 1913
- Kurosapolipus Husband & Li, 1993
- Locustacarus Ewing, 1924
- Locustipolipus Lo, 1990
- Orthapolipus Husband & Li, 1993
- Ovacarus Stannard & Vaishampayan, 1971
- Panesthipolipus Husband, 1984
- Parobia Seeman & Nahrung, 2003
- Peripolipus Husband, 1984
- Podapolipoides Regenfuss, 1968
- Podapolipus Rovelli & Grassi, 1888
- Regenopolipus Husband, 1986
- Rhinopolipus Husband & Kurosa, 2000
- Rhynchopolipus Husband & Flechtmann, 1972
- Scarabapolipus Husband & Kurosa, 1993
- Silphopolipus Kurosa, Khaustov & Husband, 2004
- Simalurapolipus Kurosa & Husband, 2013
- Stenopolipus Husband, 1984
- Stigmacarus Feldman-Muhsam & Havivi, 1977
- Tarsopolipus Berlese, 1911
- Tenebrapolipus Kurosa & Husband, 2001
- Tetrapolipus Berlese, 1911
- Wetapolipus Husband & Zhang, 2002
- Podothrombiidae
- Pomerantziidae
- Pontarachnidae
- Protziidae
- Pseudocheylidae
- Psorergatidae
- Pterygosomatidae
- Pyemotidae
- Pygmephoridae
- Raphignathidae
- Resinacaridae
- Rhagidiidae
- Rhynchohydracaridae
- Rutripalpidae
- Scutacaridae
- Siteroptidae
- Smarididae
- Smaridiidae
- Sperchontidae
- Sphaerolichidae
- 长须螨科 Stigmaeidae
- Stigmocheylidae
- Strandtmanniidae
- Stygothrombidiidae
- Stygothrombiidae
- Stygotoniidae
- Syringophilidae
- Tanaupodidae
- Tarsocheylidae
- Tarsonemidae
- Teneriffiidae
- Tenuipalpidae
- Teratothyadidae
- Teratothyasidae
- Tetranychidae
- Teutoniidae
- Thermacaridae
- Torrenticolidae
- Triasacaridae
- Triophtydeidae
- Trochometridiidae
- Trombellidae
- 恙蟎科 Trombiculidae
- Trombidiidae
- 杜克螨科 Tuckerellidae
- 杜克螨属 Tuckerella Womersley, 1940
- Tydeidae
- Uchidastygacaridae
- Unionicolidae
- Wettinidae
- Xenocaligonellididae
- Yurebillidae
- Zelandothyadidae
- Australiothyas Cook, 1986
- Zelandothyas Cook, 1985
- 科的地位未定的属：
- Amblyceropsis Kumar, 2004
- Megameropsis Gourret, 1887
- Megameropsis aquensis Gourret, 1887
- Pseudopachygnathus Gourret, 1887
- Pseudopachygnathus maculatus Gourret, 1887
Zhang, Zhi-Qiang; Fan, Qing-Hai; Pesic, Vladimir; Smit, Harry; Bochkov, Andre V.; Khaustov, A. A.; Baker, Anne; Wohltmann, Andreas; Wen, Tinghuan; Amrine, James W.; Beron, P.; Lin, Jianzhen; Gabrys, Grzegorz; Husband, Robert. Order Trombidiformes Reuter, 1909 (PDF). Zhang, Z.-Q. (编). Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness. Magnolia Press. 2011: 129–147 [2015-12-09]. ISBN 9781869778491. （原始内容存档于2015-12-22） （英语）. 王錫杰. 恙蟲病病媒之種類與生態 (PDF). 衛生署疾病管制局研究檢驗中心. 2012-05-22 [2021-09-27]. （原始内容 (PDF)存档于2021-09-27） （中文（繁體））. {長谷川英男. 繪圖解說寄生蟲的世界.台北市: 晨星.2018年09月: 154. ISBN 9789-8644-347-6}
David Evans Walker. Hidden in Plain Sight: Mites in the Canopy. Margaret Lowman, H. Bruce Rinker (编). Forest Canopies. Physiological Ecology Series 2nd. Academic Press. 2004: 224–241. ISBN 9780124575530. Norton and Behan-Pelletier (2009)
OConnor, B.M. Astigmatina. Chapter 16. Krantz, G.W. & Walter, D.E. (编). A Manual of Acarology 3rd Edition. Lubbock: Texas Tech. University Press. 2009: pp. 565–657.
Ian M. Smith & David R. Cook (1997) Description of Amoenacarus dixiensis gen. nov., sp. nov., and proposal of Amoenacaridae fam. nov. (Acari: Hydrachnida: Arrenuroidea), International Journal of Acarology, 23:2, 107-112, DOI: 10.1080/01647959708683106
Ian M. Smith (1998) Chelohydracarus navarrensis gen. nov., sp. nov. (Acari: Hydrachnida: Athienemanniidae), International Journal of Acarology, 24:4, 327-330, DOI: 10.1080/01647959808683599
Saeed Paktinat Saeej, Mohammad Bagheri, Alireza Saboori & Edward A. Ueckermann (2014) Hexabdella persiaensis sp. nov. (Acari: Prostigmata: Bdellidae) as a first new species of the genus Hexabdella from Asia, International Journal of Acarology, 40:5, 384-389, DOI: 10.1080/01647954.2014.928366
Güldem Dönel guldem-donel80@hotmail.com , Owen D. Seeman owen.seeman@qm.qld.gov.au & Salíh Doğan salihdogan@erzincan.edu.tr (2012) The first Paratydeidae (Trombidiformes: Paratydeoidea) in Turkey: Scolotydaeus anatolicus sp. nov., International Journal of Acarology, 38:5, 436-444, DOI: 10.1080/01647954.2012.669527
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