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Giardia

January 10, 2024

Not to be confused with Girardia.

Giardia (/dʒiːˈɑːrdiə/ or /ˈdʒɑːrdiə/) is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates, causing the disease giardiasis. Their life cycle alternates between a swimming trophozoite and an infective, resistant cyst. Giardia were first described by the Dutch microscopist Antonie van Leeuwenhoek in 1681.[3] The genus is named after French zoologist Alfred Mathieu Giard.[4]

Giardia
Giardia trophozoite, SEM
Scientific classification
Domain: Eukaryota
Phylum: Metamonada
Order: Diplomonadida
Family: Hexamitidae
Subfamily: Giardiinae
Genus: Giardia
Künstler, 1882[1]
Species
Synonyms
  • Lamblia R. Blanchard, 1888[2]

Characteristics edit

Like other diplomonads, Giardia have two nuclei, each with four associated flagella, and were thought to lack both mitochondria and Golgi apparatuses. However, they are now known to possess a complex endomembrane system as well as mitochondrial remnants, called mitosomes, through mitochondrial reduction.[5][6][7][8] The mitosomes are not used in ATP synthesis the way mitochondria are, but are involved in the maturation of iron-sulfur proteins.[9] The synapomorphies of genus Giardia include cells with duplicate organelles, absence of cytostomes, and ventral adhesive disc.[10]

Systematics edit

About 40 species have been described, but most of them are probably synonyms.[11] Currently, five to six morphologically distinct species are recognised.[12] Giardia duodenalis (=G. intestinalis, =G. lamblia) infect humans and other mammals, G. microti infects voles, G. muris is found in other mammals, G. ardeae and G. psittaci in birds, and G. agilis in amphibians.[4] Other described (but not certainly valid), species include:[13]

  • Giardia ardeae
  • 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 psittaci
  • Giardia recurvirostrae
  • Giardia sanguinis
  • Giardia serpentis
  • Giardia simoni
  • Giardia sturnellae
  • Giardia suricatae
  • Giardia tucani
  • Giardia varani
  • Giardia viscaciae
  • Giardia wenyoni

Real-time polymerase chain reaction (PCR) tests have been developed to detect specific species of Giardia. Gene probe can also used to differentiate between species of Giardia. A more common and less time-consuming means of identifying different species of Giardia includes microscopy and immunofluorescence techniques.[14]

Genetic and biochemical studies have revealed the heterogeneity of Giardia duodenalis, which contains probably at least eight lineages or cryptic species.[15]

Phylogeny edit

The phylogeny of Giardia is unclear, but two main theories exist. Firstly, Giardia may be extremely primitive eukaryotes that branched off early from other members of their group. This theory is supported by several features: their lack of complete mitochondria (see Characteristics) and other organelles, their primitive metabolic pathways, and their position on a phylogenetic tree.[16] However, many of these differences have been refuted in recent years, and many researchers are supporting a second theory: that Giardia are highly evolved parasites, which have lost ancestral characteristics.[17]

Genome 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.[18]

A second isolate (the B assemblage) from humans has been sequenced along with a species from a pig (the E assemblage).[19] 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.

Infection edit

 
An SEM micrograph of the small intestine of a gerbil infested with Giardia reveals a mucosa surface almost entirely obscured by attached trophozoites
Main article: Giardiasis

Giardia lives in the intestines of infected humans or other animals, individuals of which become infected by ingesting or coming into contact with contaminated foods, soil, or water tainted by the feces of an infected carrier.[20]

The symptoms of Giardia, which may begin to appear 2 days after infection, can include mild to violent diarrhoea, excess gas, stomach or abdominal cramps, upset stomach, and nausea. Resulting dehydration and nutritional loss may need immediate treatment. A typical infection can be slight, resolve without treatment, and last between 2 and 6 weeks, although it can sometimes last longer and/or be more severe. Coexistence with the parasite is possible (symptoms fade), but an infected individual 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 anthelmintic (anti-worm) property as well, ideal for certain compounded issues when a general vermicidal agent is preferred. Giardia causes a disease called giardiasis, which causes the villi of the small intestine to atrophy and flatten, resulting in malabsorption in the intestine. Lactose intolerance can persist after the eradication of Giardia from the digestive tract.[21]

Prevalence edit

The prevalence of the infection depends on different factors; while the prevalence is estimated around 2% in some developed countries, in other countries from Asia, Africa or Latin America, the prevalence can be estimated between 20% and 40%. In some patients, giardiasis can be completely asymptomatic, so many more cases are estimated.[22] The diagnostic method used can also infer in the identification and thus the count of cases. Due to their lack of knowledge and overall behavioral patterns, children aged under 5 years, are the population with the most reported infections.[23]

See also edit

References edit

  1. ^ Künstler, J. (1882). "Sur cinq protozoaires parasites nouveaux". C. R. Acad. Sci. Paris. 95: 347–349.
  2. ^ Blanchard, R. (1888). "Remarques sur le megastome intestinal". Bull. Soc. Zool. Fr. 30: 18–19.
  3. ^ Stanley L. Erlandsen; Ernest A. Meyer (1 March 1984). Giardia and Giardiasis: Biology, Pathogenesis, and Epidemiology. Springer. pp. 131–. ISBN 978-0-306-41539-5.
  4. ^ a b Adam RD (July 2001). "Biology of Giardia lamblia". Clin. Microbiol. Rev. 14 (3): 447–75. doi:10.1128/CMR.14.3.447-475.2001. PMC 88984. PMID 11432808.
  5. ^ Tovar, Jorge; León-Avila, Gloria; Sánchez, Lidya; Sutak, Robert; Tachezy, Jan; van der Giezen, Mark; Hernández, Manuel; Müller, Miklós; Lucocq, John (2003). "Mitochondrial remnant organelles of Giardia function in iron-sulphur protein maturation". Nature. 426 (6963): 172–176. Bibcode:2003Natur.426..172T. doi:10.1038/nature01945. PMID 14614504. S2CID 4402808.
  6. ^ Anna Karnkowska; et al. (May 2016). "A Eukaryote without a Mitochondrial Organelle". Current Biology. 26 (10): 1274–1284. doi:10.1016/j.cub.2016.03.053. PMID 27185558.
  7. ^ Soltys BJ, Falah M, Gupta RS (July 1996). "Identification of endoplasmic reticulum in the primitive eukaryote Giardia lamblia using cryoelectron microscopy and antibody to Bip". J. Cell Sci. 109 (Pt 7): 1909–17. doi:10.1242/jcs.109.7.1909. PMID 8832413.
  8. ^ Dolezal P; Smíd O; Rada P; et al. (August 2005). "Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting". Proc. Natl. Acad. Sci. U.S.A. 102 (31): 10924–9. Bibcode:2005PNAS..10210924D. doi:10.1073/pnas.0500349102. PMC 1182405. PMID 16040811.
  9. ^ Tovar J, et al. (2003). "Mitochondrial remnant organelles of Giardia function in iron-sulphur protein maturation". Nature. 426 (6963): 172–6. Bibcode:2003Natur.426..172T. doi:10.1038/nature01945. PMID 14614504. S2CID 4402808.
  10. ^ Cepicka, Ivan (September 2008). "Fornicata". Tree of Life Web Project.
  11. ^ Meyer E.A.; Radulescu S. (1979). "Giardia and Giardiasis". Advances in Parasitology. 17: 1–47. doi:10.1016/S0065-308X(08)60548-5. ISBN 9780120317172. PMID 395833.
  12. ^ Brusca, R.C.; Brusca, G.J. (2003). Invertebrates (2 ed.). Sinauer Associates. ISBN 0878930973.
  13. ^ "Giardia Kunstler". Tree of Life Web Project. September 2008.
  14. ^ Mahbubani 1992
  15. ^ Thompson RC, Monis PT (2004). "Variation in Giardia: implications for taxonomy and epidemiology". Advances in Parasitology. 58: 69–137. doi:10.1016/S0065-308X(04)58002-8. ISBN 9780120317585. PMID 15603762.
  16. ^ Ye, Qingqing; Tian, Haifeng; Chen, Bing; Shao, Jingru; Qin, Yan; Wen, Jianfan (25 August 2017). "Giardia's primitive GPL biosynthesis pathways with parasitic adaptation 'patches': implications for Giardia's evolutionary history and for finding targets against Giardiasis". Scientific Reports. 7 (1): 9507. Bibcode:2017NatSR...7.9507Y. doi:10.1038/s41598-017-10054-1. ISSN 2045-2322. PMC 5573378. PMID 28842650.
  17. ^ Lloyd, David; Harris, Janine C (1 March 2002). "Giardia: highly evolved parasite or early branching eukaryote?". Trends in Microbiology. 10 (3): 122–127. doi:10.1016/S0966-842X(02)02306-5. ISSN 0966-842X. PMID 11864821.
  18. ^ 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.
  19. ^ Jerlström-Hultqvist J, Ankarklev J, Svärd SG (2010). "Is human giardiasis caused by two different Giardia species?". Gut Microbes. 1 (6): 379–82. doi:10.4161/gmic.1.6.13608. PMC 3056102. PMID 21468219.
  20. ^ Filice, F.P. (1952). "Studies on the cytology and life history of a Giardia from the laboratory rat". U. C. Publications in Zoology. Berkeley CA: University of California Press. 5sex7 (2).
  21. ^ LaCour 2003
  22. ^ Hörman, A.; Korpela, H.; Wedel, H.; Sutinen, J.; Hanninen, ML. (2004). "Meta-analysis in assessment of the prevalence and annual incidence of Giardia spp. and Cryptosporidium spp. infections in humnas in the Nordic countries". Int J Parasitol. 34 (12): 1337–1346. doi:10.1016/j.ijpara.2004.08.009. PMID 15542094.
  23. ^ Savioli, L.; Smith, H.; Thompson, A. (2006). "Giardia and Cryptosporidium join the "Neglected Diseases Initiative"". Trends Parasitol. 22 (5): 160–167. doi:10.1016/j.pt.2006.02.015. PMID 16545611.

External links edit

  • "Giardia". Parasites. Centers for Disease Control and Prevention. March 2011.
  • Mahbubani MH, Bej AK, Perlin MH, Schaefer FW, Jakubowski W, Atlas RM (January 1992). "Differentiation of Giardia duodenalis from other Giardia spp. by using polymerase chain reaction and gene probes". J. Clin. Microbiol. 30 (1): 74–8. doi:10.1128/JCM.30.1.74-78.1992. PMC 264999. PMID 1734070.
  • LaCour, Michelle (2003). "Who Is Giardia?". GIARDIA. Stanford University.
  • "Giardia". NCBI Taxonomy Browser. 5740.

January 10, 2024
giardia, confused, with, girardia, ɑːr, ɑːr, genus, anaerobic, flagellated, protozoan, parasites, phylum, metamonada, that, colonise, reproduce, small, intestines, several, vertebrates, causing, disease, giardiasis, their, life, cycle, alternates, between, swi. Not to be confused with Girardia Giardia dʒ iː ˈ ɑːr d i e or ˈ dʒ ɑːr d i e is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada that colonise and reproduce in the small intestines of several vertebrates causing the disease giardiasis Their life cycle alternates between a swimming trophozoite and an infective resistant cyst Giardia were first described by the Dutch microscopist Antonie van Leeuwenhoek in 1681 3 The genus is named after French zoologist Alfred Mathieu Giard 4 GiardiaGiardia trophozoite SEMScientific classificationDomain EukaryotaPhylum MetamonadaOrder DiplomonadidaFamily HexamitidaeSubfamily GiardiinaeGenus GiardiaKunstler 1882 1 SpeciesGiardia agilis Giardia ardeae Giardia lamblia Giardia microti Giardia muris Giardia psittaciSynonymsLamblia R Blanchard 1888 2 Contents 1 Characteristics 2 Systematics 3 Phylogeny 4 Genome 5 Infection 6 Prevalence 7 See also 8 References 9 External linksCharacteristics editLike other diplomonads Giardia have two nuclei each with four associated flagella and were thought to lack both mitochondria and Golgi apparatuses However they are now known to possess a complex endomembrane system as well as mitochondrial remnants called mitosomes through mitochondrial reduction 5 6 7 8 The mitosomes are not used in ATP synthesis the way mitochondria are but are involved in the maturation of iron sulfur proteins 9 The synapomorphies of genus Giardia include cells with duplicate organelles absence of cytostomes and ventral adhesive disc 10 Systematics editAbout 40 species have been described but most of them are probably synonyms 11 Currently five to six morphologically distinct species are recognised 12 Giardia duodenalis G intestinalis G lamblia infect humans and other mammals G microti infects voles G muris is found in other mammals G ardeae and G psittaci in birds and G agilis in amphibians 4 Other described but not certainly valid species include 13 Giardia ardeae 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 psittaci Giardia recurvirostrae Giardia sanguinis Giardia serpentis Giardia simoni Giardia sturnellae Giardia suricatae Giardia tucani Giardia varani Giardia viscaciae Giardia wenyoni Real time polymerase chain reaction PCR tests have been developed to detect specific species of Giardia Gene probe can also used to differentiate between species of Giardia A more common and less time consuming means of identifying different species of Giardia includes microscopy and immunofluorescence techniques 14 Genetic and biochemical studies have revealed the heterogeneity of Giardia duodenalis which contains probably at least eight lineages or cryptic species 15 Phylogeny editThe phylogeny of Giardia is unclear but two main theories exist Firstly Giardia may be extremely primitive eukaryotes that branched off early from other members of their group This theory is supported by several features their lack of complete mitochondria see Characteristics and other organelles their primitive metabolic pathways and their position on a phylogenetic tree 16 However many of these differences have been refuted in recent years and many researchers are supporting a second theory that Giardia are highly evolved parasites which have lost ancestral characteristics 17 Genome editA 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 18 A second isolate the B assemblage from humans has been sequenced along with a species from a pig the E assemblage 19 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 Infection edit nbsp An SEM micrograph of the small intestine of a gerbil infested with Giardia reveals a mucosa surface almost entirely obscured by attached trophozoitesMain article Giardiasis Giardia lives in the intestines of infected humans or other animals individuals of which become infected by ingesting or coming into contact with contaminated foods soil or water tainted by the feces of an infected carrier 20 The symptoms of Giardia which may begin to appear 2 days after infection can include mild to violent diarrhoea excess gas stomach or abdominal cramps upset stomach and nausea Resulting dehydration and nutritional loss may need immediate treatment A typical infection can be slight resolve without treatment and last between 2 and 6 weeks although it can sometimes last longer and or be more severe Coexistence with the parasite is possible symptoms fade but an infected individual 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 anthelmintic anti worm property as well ideal for certain compounded issues when a general vermicidal agent is preferred Giardia causes a disease called giardiasis which causes the villi of the small intestine to atrophy and flatten resulting in malabsorption in the intestine Lactose intolerance can persist after the eradication of Giardia from the digestive tract 21 Prevalence editThe prevalence of the infection depends on different factors while the prevalence is estimated around 2 in some developed countries in other countries from Asia Africa or Latin America the prevalence can be estimated between 20 and 40 In some patients giardiasis can be completely asymptomatic so many more cases are estimated 22 The diagnostic method used can also infer in the identification and thus the count of cases Due to their lack of knowledge and overall behavioral patterns children aged under 5 years are the population with the most reported infections 23 See also editList of parasites human References edit Kunstler J 1882 Sur cinq protozoaires parasites nouveaux C R Acad Sci Paris 95 347 349 Blanchard R 1888 Remarques sur le megastome intestinal Bull Soc Zool Fr 30 18 19 Stanley L Erlandsen Ernest A Meyer 1 March 1984 Giardia and Giardiasis Biology Pathogenesis and Epidemiology Springer pp 131 ISBN 978 0 306 41539 5 a b Adam RD July 2001 Biology of Giardia lamblia Clin Microbiol Rev 14 3 447 75 doi 10 1128 CMR 14 3 447 475 2001 PMC 88984 PMID 11432808 Tovar Jorge Leon Avila Gloria Sanchez Lidya Sutak Robert Tachezy Jan van der Giezen Mark Hernandez Manuel Muller Miklos Lucocq John 2003 Mitochondrial remnant organelles of Giardia function in iron sulphur protein maturation Nature 426 6963 172 176 Bibcode 2003Natur 426 172T doi 10 1038 nature01945 PMID 14614504 S2CID 4402808 Anna Karnkowska et al May 2016 A Eukaryote without a Mitochondrial Organelle Current Biology 26 10 1274 1284 doi 10 1016 j cub 2016 03 053 PMID 27185558 Soltys BJ Falah M Gupta RS July 1996 Identification of endoplasmic reticulum in the primitive eukaryote Giardia lamblia using cryoelectron microscopy and antibody to Bip J Cell Sci 109 Pt 7 1909 17 doi 10 1242 jcs 109 7 1909 PMID 8832413 Dolezal P Smid O Rada P et al August 2005 Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting Proc Natl Acad Sci U S A 102 31 10924 9 Bibcode 2005PNAS 10210924D doi 10 1073 pnas 0500349102 PMC 1182405 PMID 16040811 Tovar J et al 2003 Mitochondrial remnant organelles of Giardia function in iron sulphur protein maturation Nature 426 6963 172 6 Bibcode 2003Natur 426 172T doi 10 1038 nature01945 PMID 14614504 S2CID 4402808 Cepicka Ivan September 2008 Fornicata Tree of Life Web Project Meyer E A Radulescu S 1979 Giardia and Giardiasis Advances in Parasitology 17 1 47 doi 10 1016 S0065 308X 08 60548 5 ISBN 9780120317172 PMID 395833 Brusca R C Brusca G J 2003 Invertebrates 2 ed Sinauer Associates ISBN 0878930973 Giardia Kunstler Tree of Life Web Project September 2008 Mahbubani 1992 Thompson RC Monis PT 2004 Variation in Giardia implications for taxonomy and epidemiology Advances in Parasitology 58 69 137 doi 10 1016 S0065 308X 04 58002 8 ISBN 9780120317585 PMID 15603762 Ye Qingqing Tian Haifeng Chen Bing Shao Jingru Qin Yan Wen Jianfan 25 August 2017 Giardia s primitive GPL biosynthesis pathways with parasitic adaptation patches implications for Giardia s evolutionary history and for finding targets against Giardiasis Scientific Reports 7 1 9507 Bibcode 2017NatSR 7 9507Y doi 10 1038 s41598 017 10054 1 ISSN 2045 2322 PMC 5573378 PMID 28842650 Lloyd David Harris Janine C 1 March 2002 Giardia highly evolved parasite or early branching eukaryote Trends in Microbiology 10 3 122 127 doi 10 1016 S0966 842X 02 02306 5 ISSN 0966 842X PMID 11864821 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 Jerlstrom Hultqvist J Ankarklev J Svard SG 2010 Is human giardiasis caused by two different Giardia species Gut Microbes 1 6 379 82 doi 10 4161 gmic 1 6 13608 PMC 3056102 PMID 21468219 Filice F P 1952 Studies on the cytology and life history of a Giardia from the laboratory rat U C Publications in Zoology Berkeley CA University of California Press 5sex7 2 LaCour 2003 Horman A Korpela H Wedel H Sutinen J Hanninen ML 2004 Meta analysis in assessment of the prevalence and annual incidence of Giardia spp and Cryptosporidium spp infections in humnas in the Nordic countries Int J Parasitol 34 12 1337 1346 doi 10 1016 j ijpara 2004 08 009 PMID 15542094 Savioli L Smith H Thompson A 2006 Giardia and Cryptosporidium join the Neglected Diseases Initiative Trends Parasitol 22 5 160 167 doi 10 1016 j pt 2006 02 015 PMID 16545611 External links edit Giardia Parasites Centers for Disease Control and Prevention March 2011 Mahbubani MH Bej AK Perlin MH Schaefer FW Jakubowski W Atlas RM January 1992 Differentiation of Giardia duodenalis from other Giardia spp by using polymerase chain reaction and gene probes J Clin Microbiol 30 1 74 8 doi 10 1128 JCM 30 1 74 78 1992 PMC 264999 PMID 1734070 LaCour Michelle 2003 Who Is Giardia GIARDIA Stanford University Giardia NCBI Taxonomy Browser 5740 Retrieved from https en wikipedia org w index php title Giardia amp oldid 1188339906, wikipedia, wiki, book, books, library,

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