View source for Cryptosporidium

{{Short description|Genus of single-celled organisms}}
{{About|the protozoan|the disease|Cryptosporidiosis}}
{{Hatnote|Do not confuse Cryptosporidium (protists) with [[Cryptococcus]] (fungi).}}
{{Automatic taxobox 
| image              = Cryptosporidium muris.jpg
| image_caption      = ''Cryptosporidium muris'' [[oocyst]]s found in human feces.
| display_parents    = 10
| taxon              = Cryptosporidium
| authority          = Tyzzer, 1907
| subdivision_ranks  = Species
| subdivision        = ''[[Cryptosporidium andersoni]]''<br/>
''[[Cryptosporidium bailey]]''<br/>
''[[Cryptosporidium bovis]]''<br/>
''[[Cryptosporidium cervine]]''<br/>
''[[Cryptosporidium canis]]''<br/>
''[[Cryptosporidium cuniculus]]''<br/>
''[[Cryptosporidium ducismarci]]''<br/>
''[[Cryptosporidium fayeri]]''<br/>
''[[Cryptosporidium felis]]''<br/>
''[[Cryptosporidium fragile]]''<br/>
''[[Cryptosporidium galli]]''<br/>
''[[Cryptosporidium hominis]]''<br/>
''[[Cryptosporidium marcopodum]]''<br/>
''[[Cryptosporidium meleagridis]]''<br>
''[[Cryptosporidium molnari]]''<br/>
''[[Cryptosporidium muris]]''<br/>
''[[Cryptosporidium parvum]]''<br/>
''[[Cryptosporidium ryanae]]''<br/>
''[[Cryptosporidium saurophilum]]''<br/>
''[[Cryptosporidium serpentis]]''<br/>
''[[Cryptosporidium suis]]''<br/>
''[[Cryptosporidium ubiquitum]]''<br/>
''[[Cryptosporidium viatorum]]''<br/>
''[[Cryptosporidium wrairi]]''<br/>
''[[Cryptosporidium xiaoi]]''
}}

'''''Cryptosporidium''''', sometimes informally called '''crypto''',<!--Compare analogous clinical usage, such as "strep" for [[Streptococcus]] and "staph" for [[Staphylococcus]]--> is a genus of [[apicomplexa]]n [[parasitism|parasitic]] [[alveolates]] that can cause a respiratory and [[gastrointestinal disease|gastrointestinal illness]] ([[cryptosporidiosis]]) that primarily involves [[diarrhea|watery diarrhea]] (intestinal cryptosporidiosis) with or without a persistent cough (respiratory cryptosporidiosis) in both [[immunocompetent]] and [[immunodeficient]] humans.<ref name="Respiratory cryptosporidiosis - fomite transmission">{{cite journal | vauthors = Sponseller JK, Griffiths JK, Tzipori S | title = The evolution of respiratory Cryptosporidiosis: evidence for transmission by inhalation | journal = Clinical Microbiology Reviews | volume = 27 | issue = 3 | pages = 575–86 | date = July 2014 | pmid = 24982322 | pmc = 4135895 | doi = 10.1128/CMR.00115-13 | quote = Recent evidence indicates that respiratory cryptosporidiosis may occur commonly in immunocompetent children with cryptosporidial diarrhea and unexplained cough. Findings from animal models, human case reports, and a few epidemiological studies suggest that Cryptosporidium may be transmitted via respiratory secretions, in addition to the more recognized fecal-oral route.&nbsp;... Upper respiratory cryptosporidiosis may cause inflammation of the nasal mucosa, sinuses, larynx, and trachea, accompanied by nasal discharge and voice change (54, 61, 62). Cryptosporidiosis of the lower respiratory tract typically results in productive cough, dyspnea, fever, and hypoxemia (63,–66).&nbsp;... While fecal-oral transmission is indisputably the major route of infection, transmission via coughing and fomites is also possible in situations of close contact (20).&nbsp;... Because they lacked gastrointestinal symptoms and oocyst excretion, the latter cases establish the possibility of primary respiratory infection with Cryptosporidium, which may have been acquired by inhalation of expectorated droplets or by contact with fomites.&nbsp;... This finding suggests that respiratory cryptosporidiosis may occur commonly in immunocompetent individuals. }}</ref><ref>{{Cite journal|last=Chalmers|first=Rachel M.|last2=Davies|first2=Angharad P.|last3=Tyler|first3=Kevin|date=2019-05-01|title=Cryptosporidium|url=https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000764|journal=Microbiology|language=en|volume=165|issue=5|pages=500–502|doi=10.1099/mic.0.000764|issn=1350-0872}}</ref>

Treatment of gastrointestinal infection in humans involves [[management of dehydration|fluid rehydration]], electrolyte replacement, and management of any pain. {{As of|January 2015}}, [[nitazoxanide]] is the only drug approved for the treatment of [[cryptosporidiosis]] in immunocompetent hosts.<ref name="MS Crypto treatment" />  Supplemental zinc may improve symptoms,<ref name="MS Crypto treatment">{{cite web|vauthors=Cabada MM, White AC, Venugopalan P, Sureshbabu J |editor=Bronze MS|title=Cryptosporidiosis Treatment & Management|url=http://emedicine.medscape.com/article/215490-treatment#showall|website=Medscape|publisher=WebMD|access-date=8 January 2016|date=18 August 2015|quote=Infection may improve with nutritional supplementation, particularly with regimens including zinc or glutamine.&nbsp;... Nitazoxanide significantly shortens the duration of diarrhea and can decrease the risk of mortality in malnourished children.[22] Trials have also demonstrated efficacy in adults.[26, 27]&nbsp;... Symptomatic therapy includes replacement of fluids, provision of appropriate nutrition, and treatment with antimotility agents.&nbsp;... Replacement of fluids and electrolytes is the critically important first step in the management of cryptosporidiosis, particularly in patients with large diarrheal losses. Fluids should include sodium, potassium, bicarbonate, and glucose.}}</ref> particularly in recurrent or persistent infections or in others at risk for [[zinc deficiency]].  ''Cryptosporidium'' oocysts are 4–6&nbsp;[[μm]] in diameter and exhibit partial [[acid-fast]] staining. They must be differentiated from other partially acid-fast organisms including ''[[Cyclospora cayetanensis]]''.

== General characteristics ==
''Cryptosporidium'' causes [[cryptosporidiosis]], an infection that may present as a [[diarrhea|diarrhoea]]l with or without a persistent cough in immunocompetent hosts.<ref name="Respiratory cryptosporidiosis - fomite transmission" />  Other [[apicomplexan]] pathogens include the [[malaria]] parasite ''[[Plasmodium]]'' and the [[toxoplasmosis]] parasite ''[[Toxoplasma]]''.  Unlike ''Plasmodium'', which transmits via a [[mosquito]] vector, ''Cryptosporidium'' does not use an insect vector, and is capable of completing its lifecycle within a single host, resulting in [[cyst]] stages that are excreted in feces or through inhalation of coughed on [[fomites]] and are capable of transmission to a new host.<ref name="Respiratory cryptosporidiosis - fomite transmission" /><ref name=CDC_Site>{{cite web | title = Parasites - Cryptosporidium (also known as "Crypto") | url = https://www.cdc.gov/parasites/crypto/pathogen.html | publisher = Centers for Disease Control and Prevention | date = February 20, 2015 }}</ref><ref name="WidmerCarmena2020">{{cite journal|last1=Widmer|first1=Giovanni|last2=Carmena|first2=David|last3=Kváč|first3=Martin|last4=Chalmers|first4=Rachel M.|last5=Kissinger|first5=Jessica C.|last6=Xiao|first6=Lihua|last7=Sateriale|first7=Adam|last8=Striepen|first8=Boris|last9=Laurent|first9=Fabrice|last10=Lacroix-Lamandé|first10=Sonia|last11=Gargala|first11=Gilles|last12=Favennec|first12=Loïc|title=Update on ''Cryptosporidium'' spp.: highlights from the Seventh International Giardia and Cryptosporidium Conference|journal=Parasite|volume=27|year=2020|pages=14|issn=1776-1042|doi=10.1051/parasite/2020011|url=https://www.parasite-journal.org/articles/parasite/full_html/2020/01/parasite200029/parasite200029.html|doi-access=free}} {{open access}}</ref>

A number of ''Cryptosporidium'' species infect mammals. In humans, the [[Portal:Main|main]] causes of disease are ''C. parvum'' and ''C. hominis'' (previously ''C. parvum'' genotype 1). ''C. canis'', ''C. felis'', ''C. meleagridis'', and ''C. muris'' can also cause disease in humans.<ref name=CDC_Site/>

Cryptosporidiosis is typically an acute, short-term infection, can be recurrent through reinfection in immunocompetent hosts, and become severe or life-threatening in immunocompromised individuals. In humans, it remains in the lower intestine and may remain for up to five weeks.<ref name=CDC_Site/> The parasite is transmitted by environmentally hardy [[cyst]]s (oocysts) that, once ingested, exist in the [[small intestine]] and result in an infection of intestinal [[Epithelium|epithelial tissue]].<ref name=CDC_Site/> Transmission by ingestion or inhalation of coughed on fomites is a second, less likely route of infection.<ref name="Respiratory cryptosporidiosis - fomite transmission" />

The [[genome]] of ''Cryptosporidium parvum'', sequenced in 2004, was found to be unusual amongst [[eukaryote]]s in that the [[mitochondria]] seem not to [[mitochondrial DNA|contain DNA]].<ref>{{cite journal | vauthors = Abrahamsen MS, Templeton TJ, Enomoto S, Abrahante JE, Zhu G, Lancto CA, Deng M, Liu C, Widmer G, Tzipori S, Buck GA, Xu P, Bankier AT, Dear PH, Konfortov BA, Spriggs HF, Iyer L, Anantharaman V, Aravind L, Kapur V | title = Complete genome sequence of the apicomplexan, Cryptosporidium parvum | journal = Science | volume = 304 | issue = 5669 | pages = 441–5 | date = April 2004 | pmid = 15044751 | doi = 10.1126/science.1094786 }}</ref> A closely related species, ''C. hominis'', also has its genome sequence available.<ref>{{cite journal | vauthors = Xu P, Widmer G, Wang Y, Ozaki LS, Alves JM, Serrano MG, Puiu D, Manque P, Akiyoshi D, Mackey AJ, Pearson WR, Dear PH, Bankier AT, Peterson DL, Abrahamsen MS, Kapur V, Tzipori S, Buck GA | title = The genome of Cryptosporidium hominis | journal = Nature | volume = 431 | issue = 7012 | pages = 1107–12 | date = October 2004 | pmid = 15510150 | doi = 10.1038/nature02977 | doi-access = free }}</ref>

==Life cycle==
[[Image:Cryptosporidiosis 01.png|thumb|right|300px|Life cycle of ''Cryptosporidium'' spp.]]
Cryptosporidium has three developmental stages: [[meronts]], [[gamonts]] and [[oocysts]].<ref>{{cite web |title=Cryptosporidium |url=https://www.parasite.org.au/para-site/text/cryptosporidium-text.html |website=The Australian Society for Parasitology Inc. |access-date=7 August 2019}}</ref> They reproduce within the intestinal [[epithelial cells]]. <ref name="A&O"> {{cite book |last1=Ash |first1=Lawrence |last2=Orihel |first2=Thomas |title=Ash & Orihel's Atlas of Human Parasitology |date=2007 |publisher=American Society for Clinical Pathology Press |edition=5th}}</ref> 
The ''Cryptosporidium'' [[spore]] phase ([[oocyst]]) can survive for lengthy periods outside a host. It can also resist many common [[disinfectant]]s, notably [[chlorine]]-based disinfectants.<ref>{{cite web |url=https://www.cdc.gov/ncidod/eid/vol5no4/carpenter.htm |title=Chlorine Disinfection of Recreational Water for ''Cryptosporidium parvum'' |publisher=CDC |access-date=2007-05-06}}</ref>

== Water treatment and detection ==
Many [[Water purification|treatment plants]] that take raw water from [[river]]s, [[lake]]s, and [[reservoir (water)|reservoirs]] for public [[drinking water]] production use conventional filtration technologies. Direct filtration, which is typically used to treat water with low [[suspended solids|particulate]] levels, includes coagulation and filtration but not sedimentation. Other common filtration processes including [[slow sand filter]]s,  [[Diatomaceous earth#Filtration|diatomaceous earth filters]], and membranes will remove 99% of ''Cryptosporidium''.<ref>{{cite web |url=http://www.epa.gov/safewater/mdbp/ieswtrwhatdoesitmeantoyou.pdf |title=The Interim Enhanced Surface Water Treatment Rule – What Does it Mean to You? |publisher=USEPA |access-date=2007-05-06}}</ref> Membranes and bag- and cartridge-filter products remove ''Cryptosporidium'' specifically.

''Cryptosporidium'' is highly resistant to chlorine disinfection;<ref>{{cite journal | vauthors = Korich DG, Mead JR, Madore MS, Sinclair NA, Sterling CR | title = Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability | journal = Applied and Environmental Microbiology | volume = 56 | issue = 5 | pages = 1423–8 | date = May 1990 | pmid = 2339894 | pmc = 184422 | url = }}</ref> but with high enough concentrations and contact time, ''Cryptosporidium'' inactivation will occur with [[Chlorine dioxide#Water treatment|chlorine dioxide]] and [[Ozone#Applications 2|ozone]] treatment. In general, the required levels of chlorine preclude the use of chlorine disinfection as a reliable method to control ''Cryptosporidium'' in drinking water. Ultraviolet light treatment at relatively low doses will inactivate ''Cryptosporidium''. [[Calgon Carbon]]-funded research originally discovered UV's efficacy in inactivating ''Cryptosporidium''.<ref>{{cite journal | vauthors = Bolton, JR, Dussert, B, Bukhari, Z, Hargy, TM, Clancy, JL | title = Inactivation of Cryptosporidium parvum by Medium-Pressure Ultraviolet Light in Finished Drinking Water | journal = Proc. AWWA 1998 Annual Conference, Dallas, TX | volume = A | pages = 389–403 | year = 1998 }}</ref><ref>{{cite journal | vauthors = Bukhari Z, Hargy TM, Bolton JR, Dussert B, Clancy JL | title = Medium Pressure UV Light for Oocyst Inactivation | journal = Journal of the American Water Works Association | volume = 91 | issue = 3 | pages = 86–94 | year = 1999 | doi = 10.1002/j.1551-8833.1999.tb08602.x }}</ref>

One of the largest challenges in identifying outbreaks is the ability to verify the results in a [[laboratory]].  The oocytes may be seen by microscopic examination of a stool sample, but they may be confused with other objects or artifacts similar in appearance.<ref name=Lab_Dx>{{cite journal | vauthors = Casemore DP, Armstrong M, Sands RL | title = Laboratory diagnosis of cryptosporidiosis | journal = Journal of Clinical Pathology | volume = 38 | issue = 12 | pages = 1337–41 | date = December 1985 | pmid = 2416782 | pmc = 499488 | doi = 10.1136/jcp.38.12.1337 }}</ref> Most cryptosporidia are 3–6 μm in size, although some reports have described larger cells.<ref name=Lab_Dx />

Boiling is believed to be the safest option for water contaminated by ''Cryptosporidium''.<ref>{{cite web | title = Boil water warning 'precaution' | url = http://news.bbc.co.uk/1/hi/wales/7589839.stm | work = BBC News | date =  2 September 2008 }}</ref><ref>{{cite web | title = Boil water 'into January' warning | url = http://news.bbc.co.uk/1/hi/wales/4484946.stm | work = BBC News | date = 30 November 2005 }}</ref>

==Exposure risks==

* People who swim regularly in pools with insufficient sanitation (certain strains of ''Cryptosporidium'' are chlorine-resistant)
* Child-care workers
* Parents of infected children
* People caring for other people with cryptosporidiosis
* Backpackers, hikers, and campers who drink unfiltered, untreated water
* People who visit petting farms and open farms with public access<ref>{{cite journal | vauthors = Walker MD | year = 2018 | title = Reducing the risk of zoonotic infection | journal = Conservation Land Management | volume = 16 | issue = 2 | pages = 19–22 | url = https://sites.google.com/site/cryptosporidiosisukanimal/ }}</ref>
* People, including swimmers, who swallow water from contaminated sources
* People handling infected cattle
* People exposed to human feces
* People who turn [[compost]] that has not gone through its phase where temperatures over 50ºC are reached <ref>{{Cite journal|date=1995-08-01|title=Occurrence of enteric pathogens in composted domestic solid waste containing disposable diapers|url=https://www.sciencedirect.com/science/article/abs/pii/S0734242X95900810|journal=Waste Management & Research|language=en|volume=13|issue=4|pages=315–324|doi=10.1016/S0734-242X(95)90081-0|issn=0734-242X}}</ref>

Dealing with stabilized compost - i.e. composting material that has gone through the phases where micro-organisms are digesting the organic matter and the temperature inside the composting pile has reached temperature up to 50-70ºC - poses very little risk as these temperatures kill pathogens and even make oocysts unviable.  People turning the compost should wear gloves and a breathing mask as that material contains pathogens that can make humans sick. <ref>{{Cite journal|date=1995-08-01|title=Occurrence of enteric pathogens in composted domestic solid waste containing disposable diapers|url=https://www.sciencedirect.com/science/article/abs/pii/S0734242X95900810|journal=Waste Management & Research|language=en|volume=13|issue=4|pages=315–324|doi=10.1016/S0734-242X(95)90081-0|issn=0734-242X}}</ref>

Cases of [[cryptosporidiosis]] can occur in a city with clean water; cases of cryptosporidiosis can have different origins. Like many fecal-oral pathogens, the disease can also be transmitted by contaminated food, poor hygiene or turning compost in a local [[compost]] site.  Testing of water, as well as [[epidemiological]] study, are necessary to determine the sources of specific infections. ''Cryptosporidium'' typically does not cause serious illness in healthy people. It may chronically sicken some children, as well as adults exposed and [[immunocompromised]].  A subset of the immunocompromised population is people with [[AIDS]]. Amongst [[Men who have sex with men|MSM]] with AIDS, insertive anal sex is an increased risk factor.<ref name="BMJ">{{cite journal | vauthors = Black ER, Mushlin AI, Griner PF, Suchman AL, James RL, Schoch DR | title = Predicting the need for hospitalization of ambulatory patients with pneumonia | journal = Journal of General Internal Medicine | volume = 6 | issue = 5 | pages = 394–400 | year = 2003 | pmc = 1744752 | doi = 10.1136/sti.79.5.412 | pmid = 14573839 }}</ref>  Analingus and oral-genital sex after anal-genital sex are known transmission routes.<ref name="BorchardtNoble1997">{{Cite book | first1 = Kenneth A. | last1 = Borchardt | first2 = Michael A. | last2 = Noble | name-list-style = vanc | title = Sexually Transmitted Diseases: Epidemiology, Pathology, Diagnosis, and Treatment |url= https://books.google.com/books?id=k_9sjs-n0nIC&pg=PA192 |date=25 June 1997 |publisher=CRC Press |isbn=978-0-8493-9476-8 |page=192 }}</ref>

Other transmission routes include exposure to laboratory specimens.<ref name="BorchardtNoble1997" />

== See also ==
* [[1987 Carroll County Cryptosporidiosis outbreak]]
* [[1993 Milwaukee Cryptosporidiosis outbreak]]
* [[1998 Sydney water crisis]]
* ''[[Escherichia coli]]''
* ''[[Giardia lamblia]]''

== References ==
{{Reflist}}

== Further reading ==
{{refbegin}}
* {{cite book | last = White | first = A. Clinton | chapter = Cryptosporidiosis | veditors = Mandell G | title = Principles and Practice of Infectious Diseases | edition = 6th | publisher = Elsevier | date = 2005 | pages = 3215–28 }}
* {{cite web
  | last = Upton | first = Steve J. | name-list-style = vanc
  | title = Basic Biology of ''Cryptosporidium''
  | publisher = Kansas State University: Parasitology Laboratory
  | date = 2003-09-12
  | url = http://www.k-state.edu/parasitology/basicbio
  | format = Website }}
* {{cite web
  | vauthors =  Brands SJ 
  | title = The Taxonomicon & Systema Naturae
  | work = Taxon: Genus Cryptosporidium 
  | publisher = Universal Taxonomic Services, Amsterdam, The Netherlands
  | year = 2000
  | url = http://www.taxonomy.nl/taxonomicon/TaxonTree.aspx?id=660
  | format = Website database }}
*{{Cite web|date=March 2001
  |author=United States Environmental Protection Agency
  |title=Cryptosporidium: Drinking Water Advisory
 |url=http://water.epa.gov/action/advisories/drinking/upload/2009_02_03_criteria_humanhealth_microbial_cryptoha.pdf
  |postscript=EPA reference: EPA-822-R-01-009
  |access-date=4 March 2013|author-link=United States Environmental Protection Agency
 }}
*{{Cite web|year=2009
  |author=World Health Organization
  |title=Risk Assessment of Cryptosporidium in Drinking Water
  |url=http://whqlibdoc.who.int/hq/2009/WHO_HSE_WSH_09.04_eng.pdf
  |postscript=WHO reference: WHO/HSE/WSH/09.04
  |access-date=4 March 2013|author-link=World Health Organization
 }}
{{refend}}

== External links ==
* [http://cryptoDB.org CryptoDB: The ''Cryptosporidium'' Genome Resource]

{{Eukaryota classification}}
{{Alveolata}}
{{Portal bar|Biology}}
{{Taxonbar|from=Q133078}}

[[Category:Apicomplexa genera]]
[[Category:Conoidasida]]