View source for Coccidia

{{Short description|Subclass of protists}}
{{Hatnote|Do not confuse Coccidia (a subclass of protists) with [[Coccidioides]] (a genus of fungi), [[coccidiosis]] with [[coccidioidomycosis]], nor superfamily [[scale insect|''Coccoidea'' (scale insect)]].}}
{{Automatic taxobox
| image = Coccidia.JPG
| image_alt = Coccidia oocysts in a fecal flotation from a cat. The cat was underweight and had diarrhea, showing signs of coccidiosis.
| image_caption = Coccidia [[oocyst]]s in a [[fecal flotation]] from a [[cat]]. The cat was underweight and had [[diarrhea]], showing signs of [[coccidiosis]].
| taxon = Coccidia
| authority = Leuckart, 1879
| synonyms = * Coccidiasina
| synonyms_ref = 
| subdivision_ranks = Orders
| subdivision = *[[Agamococcidiorida]]
*[[Eucoccidiorida]]
*[[Ixorheorida]]
*[[Protococcidiorida]]
}}

'''Coccidia''' ('''Coccidiasina''') are a [[Class (biology)|subclass]] of microscopic, [[spore]]-forming, single-celled [[obligate intracellular parasite]]s belonging to the [[apicomplexa]]n class [[Conoidasida]].<ref name=UTS>{{cite web | vauthors =  Brands SJ | title = The Taxonomicon & Systema Naturae | website = Taxon: Genus Cryptosporidium | publisher = Universal Taxonomic Services | location = Amsterdam, the Netherlands | year = 2000 | url = http://www.taxonomy.nl/taxonomicon/TaxonTree.aspx?id=660 | format = Website database }}</ref> 
As obligate intracellular parasites, they must live and reproduce within an [[animal]] cell. Coccidian parasites infect the intestinal tracts of animals,<ref name=iziko>{{cite web
|url=http://www.museums.org.za/bio/apicomplexa/index.htm
|title=Biodiversity explorer: Apicomplexa (apicomplexans, sporozoans)
|publisher=Iziko Museums of Cape Town
|access-date=2006-10-13
|archive-url=https://web.archive.org/web/20060923004843/http://www.museums.org.za/bio/apicomplexa/index.htm
|archive-date=2006-09-23
|url-status=dead
}}</ref> and are the largest group of apicomplexan protozoa.

Infection with these parasites is known as [[coccidiosis]]. Coccidia can infect all mammals, some birds, some fish, some reptiles, and some amphibians. Most species of coccidia are species-specific in their host. An exception is ''[[Toxoplasma gondii]]'', which can infect all mammals, although it can only undergo sexual reproduction in cats. Depending on the species of coccidia, infection can cause fever, vomiting, diarrhea, muscle pain, and nervous system effects and changes to behavior, and may lead to death. Healthy adults may recover without medication—but those who are immunocompromised or young almost certainly require medication to prevent death. Humans generally become infected by eating under-cooked meat, but can contract infection with ''T. gondii'' by poor hygiene when handling cat waste.

==Taxonomy==

The class is divided into four orders, which are distinguished by the presence or absence of various asexual and sexual stages:

*Order [[Agamococcidiorida]] Levine-1979
*Order [[Eucoccidiorida]] Léger & Duboscq-1910
*Order [[Ixorheorida]] Levine-1984
*Order [[Protococcidiorida]] Kheisin-1956

The order Eucoccidiorida is divided into two suborders. These two groups differ in their sexual development: [[Meiosis|syzygy]] for [[Adeleorina]] and independent gametes for [[Eimeriorina]].

The first suborder, Adeleorina, comprises coccidia of invertebrates and the coccidia that alternate between blood-sucking invertebrates and various vertebrates; this group includes ''[[Haemogregarina]]'' and ''[[Hepatozoon]]''. There are seven families in this suborder.

The second suborder, Eimeriorina, comprises a variety of coccidia, many of which form cysts. A number of genera, including ''[[Toxoplasma]]'' and ''[[Sarcocystis]]'', infect vertebrates.

==Coccidiosis==

===Transmission===
Infected animals spread spores called [[Apicomplexan life cycle|oocysts]] in their stool. The oocysts mature, called sporulation. When another animal passes over the location where the feces were deposited, it may pick up the spores, which it then ingests when grooming itself. Mice may ingest the spores and become infected. When another animal eats the mouse, it becomes infected.

Some species of coccidia are transmissible to humans, including [[toxoplasma]] and [[cryptosporidium]].<ref name=marvista>{{cite web|title=Coccidia|url=http://www.marvistavet.com/html/body_coccidia.html|website=Mar Vista Animal Medical Center|access-date=28 September 2015|url-status=dead|archive-url=https://web.archive.org/web/20151101031440/http://www.marvistavet.com/html/body_coccidia.html|archive-date=1 November 2015}}</ref>

===Infection===
Inside the host, the sporulated oocyst opens, and eight sporozoites are released.  Each one finds a home in an intestinal cell and starts the process of reproduction.  These offspring are called merozoites.  When the cell is stuffed full of merozoites, it bursts open, and each merozoite finds its own intestinal cell to continue the cycle.<ref name=marvista />

===Symptoms of infection===
As the infection continues, millions of intestinal cells may become infected.  As they break open, they produce a bloody, watery diarrhea.  This can cause dehydration, and can lead to death in young or small pets.<ref name=marvista /> Coccidian infections display symptoms mainly from the digestive tract including diarrhea, inflammation, intestinal pain or damage, vomiting, and irregular nutrition. These can lead to weight loss or reduced growth development, anemia, exhaustion, and even death in severe cases.<ref name=":0">{{cite journal | vauthors = Yan X, Liu M, He S, Tong T, Liu Y, Ding K, Deng H, Wang P | display-authors = 6 | title = An epidemiological study of gastrointestinal nematode and Eimeria coccidia infections in different populations of Kazakh sheep | journal = PLOS ONE | volume = 16 | issue = 5 | pages = e0251307 | date = 2021-05-19 | pmid = 34010315 | pmc = 8133398 | doi = 10.1371/journal.pone.0251307 | veditors = Clegg S | doi-access = free | bibcode = 2021PLoSO..1651307Y }}</ref>

===Diagnosis and treatment===
Coccidiosis can be diagnosed by finding oocysts in [[Stool test|fecal smears]]. In early stages of the disease, there may be very few oocysts being shed, and a negative test does not rule out the disease.

Coccidiosis is most commonly treated through the administration of [[coccidiostat]]s, a group of medications that stop coccidia from reproducing. In dogs and cats, the most commonly administered coccidiostat is [[Sulfonamide (medicine)|sulfa-based]] [[antibiotic]]s.  Once reproduction stops, the animal can usually recover on its own, a process that can take a few weeks, depending on the severity of the infection and the strength of the animal's immune system.<ref name=marvista />

== See also ==
* ''[[Cryptosporidium]]'' (the genus of organisms) and [[cryptosporidiosis]] (the resulting disease)
* ''[[Cyclospora cayetanensis]]'' (the organism) and [[cyclosporiasis]] (the resulting disease)
* [[List of parasites (human)]]    
* [[Ponazuril]], a drug used to treat protozoan infection in large animals that has shown effectiveness at treating coccidiosis in shelter puppies and kittens
* ''[[Toxoplasma gondii]]'' (the organism) and [[toxoplasmosis]] (the resulting disease)
* [[Zoalene]], a fodder additive for poultry, used to prevent infections from coccidia

== References ==
{{Reflist}}

== Further reading ==
{{Refbegin}}
* {{Cite web |vauthors=Duszynski DW, Upton SJ, Couch L |date=February 2004 |title=The Coccidia of the World |url=http://biology.unm.edu/biology/coccidia/home.html |archive-url=https://web.archive.org/web/20101230215149/http://biology.unm.edu/biology/coccidia/home.html |archive-date=2010-12-30 }}
* {{Cite journal |vauthors=Hays SM |date=October 1996 |title=Two strategies for protecting poultry from coccidia. |url=https://agresearchmag.ars.usda.gov/1996/oct/coccidia |journal=Agricultural Research |volume=44 |issue=10 |pages=12}} Describes using live-parasite vaccine versus a monoclonal antibody to block the sporozoite from invading a host's cell.
{{Refend}}

== External links ==
* {{cite web | url = http://www.takingcareofcoccidiosis.com/ | title = Coccidiosis treatment for Calves and Lambs | publisher = Janssen Animal Health | archive-url = https://web.archive.org/web/20100822152238/http://www.takingcareofcoccidiosis.com/ | archive-date = 2010-08-22 }}
* {{cite web | title = Coccidia | url = http://www.marvistavet.com/html/body_coccidia.html | publisher = Mar Vista Animal Medical Center | archive-url = https://web.archive.org/web/20151101031440/http://www.marvistavet.com/html/body_coccidia.html | archive-date = 2015-11-01 }}
* {{cite web | url = http://www.saxonet.de/coccidia/index.htm | title = Life Cycle EIMERIA | vauthors = Weck-Heimann A | date = 1996–2005 }}
* {{cite web | url = http://www.farminguk.com/vet/poultry/husbandry/vet6.htm | publisher = FarmingUK | title = Information about Coccidiosis | archive-url = https://web.archive.org/web/20061021234514/http://www.farminguk.com/vet/poultry/husbandry/vet6.htm | archive-date = 2006-10-21 }}
* {{cite EB1911 |wstitle=Coccidia |volume=6 |pages=615–618 | vauthors = Woodcock HM |short=1}}

{{Alveolata}}
{{Chromalveolate diseases}}
{{Taxonbar|from1=Q1147204|from2=Q25364012}}
{{Authority control}}

[[Category:Animal diseases]]
[[Category:Cat diseases]]
[[Category:Conoidasida]]
[[Category:Dog diseases]]
[[Category:Apicomplexa subclasses]]
[[Category:Veterinary protozoology]]