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flagellates parasitic in intestines of vertebrates
a suspected cause of diarrhea in humans

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/09/03 11:55:03」(JST)

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Giardia (/dʒiːˈɑrdiə/ or /ˈdʒɑrdiə/) is a genus of anaerobic flagellated protozoan parasites of the phylum Retortamonada in the supergroup "Excavata" (named for the excavated groove on one side of the cell body) that colonise and reproduce in the small intestines of several vertebrates, causing giardiasis. Their life cycle alternates between an actively swimming trophozoite and an infective, resistant cyst. The genus was named after French zoologist Alfred Mathieu Giard.

Characteristics[edit source | edit]

Like other diplomonads, Giardia have two nuclei, each with four associated flagella, and lack both mitochondria and a Golgi apparatus. However they are now known to possess mitochondrial relics, called mitosomes. These are not used in ATP synthesis the way mitochondria are, but are involved in the maturation of iron-sulfur proteins.^[1] The synapomorphies of genus Giardia include cells with duplicate organelles, absence of cytostomes, and ventral adhesive disc.^[2]

Infection and symptoms[edit source | edit]

A SEM micrograph of the mucosa surface of the small intestine of a gerbil infested with Giardia. The intestinal epithelial surface is almost entirely obscured by the attached trophozoites.

Main article: Giardiasis

Giardia lives inside the intestines of infected humans or other animals. Individuals become infected through ingesting or coming into contact with contaminated food, soil, or water. The Giardia parasite originates from contaminated items and surfaces that have been tainted by the feces of an infected animal.^[3]

The symptoms of Giardia, which may begin to appear 2 days after infection, include violent diarrhea, excess gas, stomach or abdominal cramps, upset stomach, and nausea. Resulting dehydration and nutritional loss may need immediate treatment. The typical infection within an individual can be slight, resolve without treatment, and last between 2–6 weeks, although sometimes longer and/or more severe. Coexistence with the parasite is possible, symptoms fade, but one can remain a carrier and transmit it to others. Medication containing tinidazole or metronidazole decreases symptoms and time to resolution, albendazole is also used and has an anti-helmintic (anti-worm) property as well, ideal for certain compounded issues when a general vermicidal agent is preferred.

Prevention[edit source | edit]

Person-to-person transmission accounts for the majority of Giardia infections and is usually associated with poor hygiene and sanitation. Water-borne transmission is associated with the ingestion of contaminated water. In the U.S., outbreaks typically occur in small water systems using inadequately treated surface water. Venereal transmission happens through fecal-oral contamination. Additionally, diaper changing and inadequate hand washing are risk factors for transmission from infected children. Lastly, food-borne epidemics of Giardia have developed through the contamination of food by infected food-handlers.^[4]

Systematics[edit source | edit]

About 40 species have been described from different animals, but many of them are probably synonyms.^[5] Currently, five to six morphologically distinct species are recognised.^[6] Giardia lamblia (=G. intestinalis, =G. duodenalis) infect humans and other mammals, G. muris is found from other mammals, G. ardeae and G. psittaci from birds, G. agilis from amphibians and G. microti from voles.^[7] Other described, (but not certainly valid) species include:^[8]

Giardia beckeri
Giardia beltrani
Giardia botauri
Giardia bovis
Giardia bradypi
Giardia canis
Giardia caprae
Giardia cati
Giardia caviae
Giardia chinchillae
Giardia dasi
Giardia equii

Giardia floridae
Giardia hegneri
Giardia herodiadis
Giardia hyderabadensis
Giardia irarae
Giardia marginalis
Giardia melospizae
Giardia nycticori
Giardia ondatrae
Giardia otomyis
Giardia pitymysi

Giardia pseudoardeae
Giardia recurvirostrae
Giardia sanguinis
Giardia serpentis
Giardia simoni
Giardia sturnellae
Giardia suricatae
Giardia tucani
Giardia varani
Giardia viscaciae
Giardia wenyoni

Genetic and biochemical studies have revealed the heterogeneity of Giardia lamblia, which contains probably at least eight lineages or cryptic species.^[9]

Genome[edit source | edit]

A Giardia isolate (WB) was the first diplomonad to have its genome sequenced. Its 11.7 million basepair genome is compact in structure and content with simplified basic cellular machineries and metabolism. Currently the genomes of several other Giardia isolates and diplomonads (the fish pathogens Spironucleus vortens and S. salmonicida) are being sequenced.^[10]

A second isolate (the B assemblage) from humans has been sequenced along with a species from a pig (the E assemblage).^[11] There are ~5000 genes in the genome. The E assemblage is more closely related to the A assemblage than is the B. A number of chromosomal rearrangements are present.

References[edit source | edit]

^ Tovar J. et al. (2003). "Mitochondrial remnant organelles of Giardia function in iron-sulphur protein maturation". Nature 426 (6963): 172–6. doi:10.1038/nature01945. PMID 14614504.
^ Cepicka, Ivan. 2008. Fornicata. Version 2 September 2008 (under construction). http://tolweb.org/Fornicata/121182/2008.09.02 in The Tree of Life Web Project, http://tolweb.org/
^ Filice, F.P. (1952) "Studies on the cytology and life history of a Giardia from the laboratory rat" U. C. Publications in Zoology. v. 57, no. 2. University of California Press: Berkeley
^ Pennardt, MD, Andre. "Giardiasis." EMedicine. 4 Feb. 2004. 20 Feb. 2009 <http://www.emedicine.com/EMERG/topic215.htm>.
^ Meyer E.A., Radulescu S. (1979). "Giardia and Giardiasis". Advances in Parasitology 17: 1–47. doi:10.1016/S0065-308X(08)60548-5. PMID 395833. "no"
^ R.C.Brusca, G.J.Brusca. Invertebrates. Sinauer Associates, 2 ed.(2003)
^ Adam,R.D. Biology of Giardia. Clinical Microbiology Reviews, July 2001, p. 447–475
^ Tree of Life Web Project. 2008. Giardia Kunstler. Version 2 September 2008 (temporary). http://tolweb.org/Giardia/97370/2008.09.02 in The Tree of Life Web Project, http://tolweb.org/
^ R.C.A. Thompson and P.T. Monis, Variation in Giardia: implications for taxonomy and epidemiology. Advances in Parasitology 58, 69-137 (2004)
^ Andersson, JO et al. (2010). "The Genome of Giardia and Other Diplomonads". Anaerobic Parasitic Protozoa: Genomics and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-61-5.
^ Jerlström-Hultqvist J, Ankarklev J, Svärd SG (2010) Is human giardiasis caused by two different Giardia species? Gut Microbes 1(6):379-382.

External links[edit source | edit]

Giardiasis - Centers for Disease Control and Prevention

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. ジアルジア症の治療および予防 treatment and prevention of giardiasis
2. ジアルジア症の疫学、臨床症状、および診断 epidemiology clinical manifestations and diagnosis of giardiasis
3. 犬からの人畜共通感染症 zoonoses from dogs
4. 好酸球の生物学および好酸球増多症の原因 eosinophil biology and causes of eosinophilia
5. 猫からの人畜共通感染症 zoonoses from cats

English Journal

In silico data analyses of recombinases GdDMC1A and GdDMC1B from Giardia duodenalis.

Torres-Huerta AL1, Martínez-Miguel RM1, Bazán-Tejeda ML1, Bermúdez-Cruz RM1.
Data in brief.Data Brief.2016 Aug 22;9:236-44. doi: 10.1016/j.dib.2016.08.031. eCollection 2016.
Giardia duodenalis is a worldwide protozoa known causing diarrhea in all vertebrates, humans among these. Homologous recombination is a mechanism that provides genomic stability. Two putative recombinases were identified in G. duodenalis genome: GdDMC1A and GdDMC1B. In this article, we describe the
PMID 27660811

Performance of microscopy and ELISA for diagnosing Giardia duodenalis infection in different pediatric groups.

Silva RK1, Pacheco FT1, Martins AS1, Menezes JF1, Costa-Ribeiro H Jr2, Ribeiro TC2, Mattos ÂP2, Oliveira RR3, Soares NM1, Teixeira MC4.
Parasitology international.Parasitol Int.2016 Dec;65(6 Pt A):635-640. doi: 10.1016/j.parint.2016.08.012. Epub 2016 Aug 30.
Techniques for Giardia diagnosis based on microscopy are usually applied as routine laboratory testing; however, they typically exhibit low sensitivity. This study aimed to evaluate Giardia duodenalis and other intestinal parasitic infections in different pediatric groups, with an emphasis on the co
PMID 27586394

Blastocystosis in post-traumatic splenectomized patients.

Karasartova D1, Gureser AS1, Zorlu M2, Turegun-Atasoy B3, Taylan-Ozkan A4, Dolapci M2.
Parasitology international.Parasitol Int.2016 Dec;65(6 Pt B):802-805. doi: 10.1016/j.parint.2015.12.004. Epub 2015 Dec 14.
BACKGROUND/AIMS: The aim of this study was to determine the prevalence and significance of intestinal protozoa, specially Blastocystis spp., and to perform PCR-based subtype classification for understanding the importance of Blastocystis spp. in the pathogenesis of gastrointestinal disorders in post
PMID 26697990

Japanese Journal

Epidemiological Studies on Intestinal Protozoa in Pigs in Saitama, Japan

YUI Takeshi,SHIBAHARA Tomoyuki,KON Marina,YAMAMOTO Norishige,KAMEDA Mitsuzumi,TANIYAMA Hiroyuki
Japan Agricultural Research Quarterly: JARQ 48(1), 87-93, 2014
… was detected in 79 pigs (23.7%) of all pigs checked, Giardia … the number of 6-month-old pigs infected with Giardia …
NAID 130003396729

寄生虫陽性率の経年的変化と寄生虫検査継続意義

小松悦子,福田弥生,鵜原日登美 [他]
人間ドック = Ningen Dock : official journal of the Japanese Society of Human Dry Dock 28(4), 641-645, 2013-12
NAID 40019935147

犬のジアルジア感染 (日本獣医師会学会学術誌) -- (小動物臨床関連部門)

伊藤直之
日本獣医師会雑誌 = Journal of the Japan Veterinary Medical Association 66(10), 701-708, 2013-10
NAID 40019830563

Related Pictures

★リンクテーブル★

リンク元	「メトロニダゾール」「ジアルジア属」「lamblia」
拡張検索	「Giardia lamblia」

「メトロニダゾール」

Giardia
	Giardia trophozoite, SEM
Scientific classification
Domain:	Eukaryota
Kingdom:	Protista
Phylum:	Sarcomastigophora
Class:	Zoomastigophora
Order:	Diplomonada
Family:	Hexamitidae
Genus:	Giardia
species
	Giardia agilis; Giardia ardeae; Giardia lamblia; Giardia muris; Giardia microti; Giardia psittaci

　　[★]

英: metronidazole, MTZ
商: フラジール Flagyl, Metro-IV、アスゾール。ランピオンパック(ランソプラゾール、アモキシシリン、メトロニダゾール)
関: トリコモナス

first aid step1 2006 p.139,142,148,165,172,178,208,276,282

特徴

原虫(トリコモナスなど)による感染症に対して用いる

構造

作用機序 PPC. 641, 647

メトロニダゾールの活性化には嫌気性生物の発酵に関与する酵素 pyruvate-derredocin oxidoreductase,PFORが必要
pyruvate-ferredoxin oxidoreductaseはferredoxinをreduced ferredoxinに変換するが、これに共役してメトロニダゾールがreduced metronidazole(活性型)に変換される。

PFORは宿主細胞(好気性生物)には存在しないので、原虫や嫌気性生物が特異的に障害を受ける

微生物の蛋白質、膜、DNAに傷害を与える

適応

USMLE (first aid step1 2006 p.172)

横隔膜より下の嫌気性菌に対して用いられる

原虫：Giardia, Entamoeba, Trichomonas
嫌気性菌：Bacteroides, Clostridium
細菌：Clostridium difficile, Helicobacter pylori, Gardnerella vaginalis

H. pylori：bismuth + amoxicillin/tetracycline + metronidazole

副作用

disulfiram-like reaction with alcohol; headache,metallic taste (first aid step1 2006 p.172)

「ジアルジア属」

　　[★]

ラ: Giardia
同: Giardia属

鞭毛虫の一属

ジアルジア属

Giardia lamblia：ランブル鞭毛虫

「lamblia」

　　[★]

;関:Giardia

関: Giardia

Giardia lamblia

「Giardia lamblia」

　　[★] ランブル鞭毛虫

(腸管に寄生する鞭毛虫)ンブル鞭毛虫

関: Giardia intestinalis

[Tovar2003-1] Tovar J. et al. (2003). "Mitochondrial remnant organelles of Giardia function in iron-sulphur protein maturation". Nature 426 (6963): 172–6. doi:10.1038/nature01945. PMID 14614504.

[2] Cepicka, Ivan. 2008. Fornicata. Version 2 September 2008 (under construction). http://tolweb.org/Fornicata/121182/2008.09.02 in The Tree of Life Web Project, http://tolweb.org/

[3] Filice, F.P. (1952) "Studies on the cytology and life history of a Giardia from the laboratory rat" U. C. Publications in Zoology. v. 57, no. 2. University of California Press: Berkeley

[pennardt_g-4] Pennardt, MD, Andre. "Giardiasis." EMedicine. 4 Feb. 2004. 20 Feb. 2009 <http://www.emedicine.com/EMERG/topic215.htm>.

[Meyer1979-5] Meyer E.A., Radulescu S. (1979). "Giardia and Giardiasis". Advances in Parasitology 17: 1–47. doi:10.1016/S0065-308X(08)60548-5. PMID 395833. "no"

[6] R.C.Brusca, G.J.Brusca. Invertebrates. Sinauer Associates, 2 ed.(2003)

[7] Adam,R.D. Biology of Giardia. Clinical Microbiology Reviews, July 2001, p. 447–475

[8] Tree of Life Web Project. 2008. Giardia Kunstler. Version 2 September 2008 (temporary). http://tolweb.org/Giardia/97370/2008.09.02 in The Tree of Life Web Project, http://tolweb.org/

[9] R.C.A. Thompson and P.T. Monis, Variation in Giardia: implications for taxonomy and epidemiology. Advances in Parasitology 58, 69-137 (2004)

[Anderssonetal-10] Andersson, JO et al. (2010). "The Genome of Giardia and Other Diplomonads". Anaerobic Parasitic Protozoa: Genomics and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-61-5.

[Jerlstr.C3.B6m-Hultqvist2010-11] Jerlström-Hultqvist J, Ankarklev J, Svärd SG (2010) Is human giardiasis caused by two different Giardia species? Gut Microbes 1(6):379-382.

匿名

検索

案内

案内

Giardia