{{short description|Parasitic disease}} 250px|thumb|Different forms of coenurus in sheep and rabbits and an adult worm '''Coenurosis''', also known as '''caenurosis''', '''coenuriasis''', '''gid''', '''dunt''' or '''sturdy''', is a parasitic infection that develops in the intermediate hosts of some tapeworm species (''Taenia multiceps'',<ref>University of Pennsylvania - Veterinary Medicine: [http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/cestodes/t_multiceps.html Taenia multiceps Homepage] {{webarchive|url=https://web.archive.org/web/20100710185558/http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/cestodes/t_multiceps.html |date=2010-07-10 }}</ref> ''T. serialis'',<ref>University of Pennsylvania - Veterinary medicine: [http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/cestodes/t_serialis.html Taenia serialis Homepage] {{webarchive|url=https://web.archive.org/web/20100710203659/http://cal.vet.upenn.edu/projects/dxendopar/parasitepages/cestodes/t_serialis.html |date=2010-07-10 }}</ref> ''T. brauni'', or ''T. glomerata''). It is caused by the coenurus, the larval stage of these tapeworms. The disease occurs mainly in sheep and other ungulates,<ref>Stanford University: [http://www.stanford.edu/group/parasites/ParaSites2005/Coenurosis/hosts.htm Coenurosis - Hosts] {{Webarchive|url=https://web.archive.org/web/20121023084706/http://www.stanford.edu/group/parasites/ParaSites2005/Coenurosis/hosts.htm |date=2012-10-23 }}</ref> but it can also occur in humans by accidental ingestion of tapeworm eggs.
Adult worms of these species develop in the small intestine of the definitive hosts (dogs, foxes and other canids), causing a disease from the group of taeniasis.<ref>Stanford University: [http://www.stanford.edu/class/humbio103/ParaSites2004/Taeniasis/index.htm Taeniasis] {{Webarchive|url=https://web.archive.org/web/20130709114351/http://www.stanford.edu/class/humbio103/ParaSites2004/Taeniasis/index.htm |date=2013-07-09 }}</ref> Humans cannot be definitive hosts for these species of tapeworms.
== History == The texts of Hippocrates describe a nervous disease of sheep consistent with the symptoms of gid, comparing its symptoms to epilepsy and describing the accumulation of bad-smelling fluid in the brain.<ref name=":12"/><ref name=":1">{{Cite book|last=Hall|first=Maurice C.|title=The gid parasite and allied species of the cestode genus Multiceps.|date=1910|publisher=U.S. Dept. of Agriculture, Bureau of Animal Industry|oclc=681930104}}</ref> However, it was only in the 1600s that clearer behavioural and necropsy descriptions were recorded, including the characteristic brain cysts and early surgical methods of removal.<ref name=":11">{{Cite book|last=Ransom|first=Brayton Howard. [from old catalog]|title=The gid parasite (Cnurus cerebralis): its presence in American sheep.|date=1905|publisher=Govt. print. off.|location=Washington|doi=10.5962/bhl.title.34582 }}</ref> The cause of these cysts was identified as an animal parasite in 1780 by Nathanael Gottfried Leske and Johann August Ephraim Goeze.<ref name=":1" /><ref name=":11" /> It was shown that the parasite could be transferred across species to and from dogs by Karl Theodor Ernst von Siebold and Friedrich Küchenmeister in the 1850s, and the species was identified as ''Taenia multiceps'' (then called ''Coenurus cerebralis'') in 1890.<ref name=":11" />
Coenurosis in humans is rare and was not diagnosed until the twentieth century, with the first recorded cases by each ''Taenia'' species being: ''T. multiceps'' in 1913,<ref name=":0">{{Cite web|title=Coenurosis|url=https://web.stanford.edu/class/humbio103/ParaSites2005/Coenurosis/hosts.htm|website=web.stanford.edu|access-date=2020-04-30}}</ref> ''T. glomerate'' in 1919,<ref name=":6">{{Cite journal|last1=Hermos|first1=John A.|last2=Healy|first2=George R.|last3=Schultz|first3=Myron G.|last4=Barlow|first4=John|last5=Church|first5=William G.|date=1970-08-31|title=Fatal Human Cerebral Coenurosis|url=https://jamanetwork.com/journals/jama/fullarticle/356362|journal=JAMA|language=en|volume=213|issue=9|pages=1461–1464|doi=10.1001/jama.1970.03170350029006|pmid=5468450|issn=0098-7484|url-access=subscription}}</ref> ''T. serialis'' in 1933,<ref name=":0" /> and ''T. brauni'' in 1956.<ref name=":6" />
== Life cycle == The eggs of ''T. multiceps'', ''T. glomerate'', ''T. serialis'', and ''T. brauni'' are shed in the feces of infected hosts into the environment.<ref name=":2">{{Cite journal|last1=Armon|first1=Robert|last2=Cheruti|first2=Uta|date=2012|title=Environmental Aspects of Zoonotic Diseases|journal=Water Intelligence Online|volume=11|doi=10.2166/9781780400761|issn=1476-1777|doi-access=free}}</ref> The eggs are then ingested by an intermediate host, where the eggs hatch in intestines and release oncospheres.<ref name=":2" /> Oncospheres are the larval form of tapeworms that contain hooks for attaching to the host's tissues.<ref name=":3">{{Cite book|last=Smyth|first=James Desmond|title=The physiology and biochemistry of cestodes|date=2007|publisher=Cambridge University Press|isbn=978-0-521-03895-9|oclc=836624725}}</ref> The oncospheres continue to move through the bloodstream of the intermediate host until they find suitable organs to inhabit.<ref name=":3" /> The oncospheres can bind to the eyes, the brain, skeletal muscle, and subcutaneous tissue. Once the oncospheres reach their destination, they take about three months to develop into coenuri.<ref name=":2" /> Coenuri are white, fluid filled structures that are 3-10 centimeters in diameter.<ref name=":4">{{Cite book|editor-last=Ryan |editor-first= Edward T. |editor2-last=Hill |editor2-first=David Russell |editor3-last=Solomon |editor3-first=Tom |editor4-last=Endy |editor4-first=Timothy P. |editor5-last=Aronson |editor5-first=Naomi |title=Hunter's tropical medicine and emerging infectious diseases|date=25 March 2019|publisher= Elsevier Health Sciences |isbn=978-0-323-62550-0|oclc=1096243611}}</ref> Coenuri have a collapsed membrane and several protoscolices on the interior.<ref name=":4" /> The coenuri cysts found in the central nervous system have multiple cavities, and those that are not have only one cavity.<ref name=":4" /> The disease is transferred to the definitive host when the host digests the tissue of the intermediate host. Next, eggs hatch in the intestine of the definitive host and circulate in the bloodstream until they reach suitable organs.<ref name=":2" />
===Hosts=== The definitive hosts for coenurosis are dogs, foxes, and other canids.<ref name=":10">{{Cite journal|last1=Rahsan|first1=Yilmaz|last2=Nihat|first2=Yumusak|last3=Bestami|first3=Yilmaz|last4=Adnan|first4=Ayan|last5=Nuran|first5=Aysul|date=2018-03-30|title=Histopathological, immunohistochemical, and parasitological studies on pathogenesis of Coenurus cerebralis in sheep|journal=Journal of Veterinary Research|volume=62|issue=1|pages=35–41|doi=10.2478/jvetres-2018-0005|pmid=29978125|pmc=5957459|issn=2450-8608|doi-access=free}}</ref> The intermediate hosts for coenurosis can vary depending on the ''Taenia'' species. In ''T. multiceps'', sheep are the intermediate hosts, but goats, cattle, horses, and antelopes are also common hosts.<ref name=":10" /> ''T. multiceps'' can affect any tissue, but it normally targets the brain in animal hosts. In ''T. serialis'', rabbits and rodents are the intermediate hosts.<ref name=":10" /> ''T. serialis'' commonly targets subcutaneous and intramuscular tissue. In ''T. brauni'' and ''T. glomerata'', gerbils are the intermediate host. ''T. brauni'' and ''T. glomerate'' larvae tend to inhabit the muscles. Intermediate hosts can be infected with either chronic or acute coenurosis.<ref name=":10" /> Chronic coenurosis is the more common form, and it occurs primarily in young sheep.{{cn|date=January 2023}}
===In wild animals=== Although coenurosis is more commonly associated with domestic animals, it has also been documented in wildlife, such as in mountain ungulates in the French Alps. It is believed that the ungulates are being contaminated by infected sheep. Understanding how this disease is transmitted from sheep to wild animals is important in managing the spread of this potentially dangerous zoonotic disease. A potential management strategy would be for farmers to dispose of animal carcasses found on their land. In Ethiopia, gelada monkeys with coenurosis were found to have higher mortality and lower reproductive success.<ref name=Schneider-Crease>{{cite journal |vauthors=Schneider-Crease I, Griffin RH, Gomery MA, Bergman TJ, Beehner JC | year = 2017 | title = High mortality associated with tapeworm parasitism in geladas (''Theropithecus gelada'') in the Simien Mountains National Park, Ethiopia | journal = American Journal of Primatology | volume = 79 | issue = 9 | article-number = e22684 | doi=10.1002/ajp.22684| pmid = 28783206 | hdl = 2027.42/138266 | s2cid = 3878796 | hdl-access = free }}</ref><ref name=Nguyen>{{cite journal |vauthors=Nguyen N, Fashing PJ, Boyd DA, Barry TS, Burke RJ, Goodale CB, Jones SC, Kerby JT, Kellogg BS, Lee LM, Miller CM, Nurmi NO, Ramsay MS, Reynolds JD, Stewart KM, Turner TJ, Venkataraman VV, Knauf Y, Roos C, Knauf S | year = 2017 | title = Fitness impacts of tapeworm parasitism on wild gelada monkeys at Guassa, Ethiopia | journal = American Journal of Primatology | volume = 77 | issue = 5 | pages = 579–594| doi = 10.1002/ajp.22379 | pmid = 25716944 | s2cid = 23714669 | doi-access = free }}</ref>
== Symptoms and diagnosis == The symptoms for coenurosis vary depending on where the cyst is located.{{cn|date=January 2023}}
== Prevention and treatment == In sheep, the usual treatment is surgical trepanation to remove the brain cyst, one of the few economically viable surgeries in farm animals.<ref name=":12">{{Cite journal|last1=Komnenou|first1=A.|last2=Dessiris|first2=A.|last3=Giadinis|first3=N.|date=2000|title=Surgical treatment of coenurosis (gid) in sheep|url=http://doi.wiley.com/10.1136/vr.147.9.242|journal=Veterinary Record|language=en|volume=147|issue=9|pages=242–244|doi=10.1136/vr.147.9.242|pmid=11014487 |s2cid=24998839 |url-access=subscription}}</ref><ref>{{Cite journal|last1=Skerritt|first1=G.|last2=Stallbaumer|first2=M.|date=1984-10-20|title=Diagnosis and treatment of coenuriasis (gid) in sheep|url=https://veterinaryrecord.bmj.com/lookup/doi/10.1136/vr.115.16.399|journal=Veterinary Record|language=en|volume=115|issue=16|pages=399–403|doi=10.1136/vr.115.16.399|pmid=6506419 |s2cid=42469802 |issn=0042-4900|url-access=subscription}}</ref> The site of the cyst can usually be estimated based on the neurological symptoms and skull thinning.<ref name=":12" /> Treated sheep typically regain sufficient function to rejoin the flock<ref name=":12" /> and necropsy indicates that the site of the cyst collapses and scars, relieving pressure on the brain.<ref>{{Cite journal|last1=Kelly|first1=D.F.|last2=Payne-Johnson|first2=C.E.|date=1993|title=Cerebral healing after craniotomy to evacuate a coenurus cerebralis cyst|url=https://linkinghub.elsevier.com/retrieve/pii/S0021997508802125|journal=Journal of Comparative Pathology|language=en|volume=108|issue=4|pages=399–403|doi=10.1016/S0021-9975(08)80212-5|pmid=8366207 |url-access=subscription}}</ref>
In the rare cases where a human is infected, both surgical and pharmaceutical treatments are available.<ref name=":02">{{Cite web|title=Coenurosis|url=https://web.stanford.edu/class/humbio103/ParaSites2005/Coenurosis/hosts.htm|access-date=2020-04-30|website=web.stanford.edu}}</ref> Since the disease is so uncommon in humans, no vaccine has been developed for it.<ref name=":02" />
== Epidemiology == * ''T. multiceps'' is commonly found in France, England, Brazil, Africa, and the United States.<ref name=":4" /> * ''T. serialis'' is found in Canada and the United States<ref name=":4" /> * ''T. brauni'' is found in North America, Rwanda, and the Republic of Congo<ref name=":4" /> * ''T. glomerata'' is found in Nigeria and the Republic of Congo<ref name=":4" />
==See also== * Coenurosis in humans * Taeniasis
==References== {{reflist}}
==External links== * Stanford University: [http://www.stanford.edu/group/parasites/ParaSites2005/Coenurosis/index.htm Coenurosis] {{Webarchive|url=https://web.archive.org/web/20120828152354/http://www.stanford.edu/group/parasites/ParaSites2005/Coenurosis/index.htm |date=2012-08-28 }}
Category:Ruminant diseases Category:Zoonotic parasitic diseases