Difference between revisions of "Coccidia"

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==Introduction==
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#REDIRECT[[:Category:Coccidia]]
 
 
[[Image:Coccidia.jpg|thumb|right|150px|Coccidia - Joel Mills]]
 
 
 
*The '''oocyst''' is the resistant stage in the environment
 
 
 
*The infective '''sporozoite''' is released from the oocyst
 
 
 
*Inside the host, the sporozoites invade the intestinal epithelial tissue
 
**Sporozoites feed and grow
 
 
 
*As the sporozoite grows the nucleus divides forming a '''schizont'''
 
 
 
*The schizont contains numerous elongated '''merozoites'''
 
 
 
*The formation of merozoites is the first asexual reproductive stage called '''schizogony'''
 
 
 
*The schizont ruptures releasing the merozoites which also invade the epithelial cells
 
 
 
*Another generation of schizonts form which is the beginning of the sexual phase of reproduction called '''gametogony'''
 
 
 
*The merozoites form male '''microgamonts''' or female '''macrogamonts'''
 
**Collectively known as gamonts or gametocytes
 
 
 
*The microgamonts released from the microgametocyte penetrate and fertilise the macrogamont (which is contained within the macrogametocyte)
 
 
 
*Gametogony forms the '''zygote'''
 
**Surrounded by a cyst wall
 
**Forms the '''oocyst'''
 
 
 
*The oocyst is passed in the faeces and is unsporulated
 
 
 
*The oocyst becomes sporulated in the second asexual reproductive phase called '''sporogony'''
 
 
 
*Once the oocyst is sporulated it is infective
 
 
 
<big>
 
'''[[Eimeria spp.|''Eimeria'' spp.]]
 
 
 
'''[[Isospora spp.|''Isospora'' spp.]]
 
 
 
'''[[Coccidiosis]]
 
 
 
'''[[Coccidia - Poultry|Coccidia of Poultry]]
 
 
 
'''[[Coccidiosis - Poultry]]
 
 
 
'''[[Coccidiosis - Turkey|Coccidia of Turkeys]]
 
 
 
'''[[Coccidiosis - Geese|Coccidia of Geese]]
 
 
 
'''[[Coccidiosis - Duck|Coccidia of Ducks]]
 
 
 
'''[[Coccidiosis - Game Birds|Coccidia of Game Birds]]
 
 
 
'''[[Coccidiosis - Cattle|Coccidia of Cattle]]
 
 
 
'''[[Coccidiosis - Sheep|Coccidia of Sheep]]
 
 
 
 
 
 
 
==Coccidia of Goats==
 
[[Image:Goats.jpg|thumb|right|150px|Goats - nabrown RVC]]
 
[[Image:Eimeria leukarti horse.jpg|thumb|right|150px|''Eimeria leukarti'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Isospora suis oocyst.jpg|thumb|right|150px|''Isospora suis'' oocyst from pig faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Isospora canis.jpg|thumb|right|150px|''Isospora canis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Coccidia.jpg|thumb|right|150px|Coccidia in Cat Faeces - Joel Mills]]
 
[[Image:Isospora felis.jpg|thumb|right|150px|''Isospora felis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
*Many ''Eimeria'' species
 
 
 
*2 ''Eimeria'' are pathogenic
 
**Cause [[Intestine Diarrhoea - Pathology|diarrhoea]] and a decreased growth rate
 
 
 
*Different species of ''Eimeria'' occurs in sheep and goats
 
 
 
==Coccidia of Horses==
 
 
 
*Only one atypical ''Eimeria''
 
 
 
*Forms large subepithelial gametocytes in villi
 
 
 
*Large, dark coloured oocysts
 
**Approximately 12μm
 
 
 
*Occasionally causes [[Intestine Diarrhoea - Pathology|diarrhoea]]
 
 
 
*''Besnoitia bennetti'' in [[Respiratory Parasitic Infections - Pathology#Besnoitia bennetti|larynx]] of horses
 
 
 
==Coccidia of Pigs==
 
*Many species of ''Eimeria'' and ''Isospora''
 
 
 
*Only ''Isospora suis'' is of clinical pathogenic importance
 
 
 
*Causes sporadic, serious and sometimes fatal disease in unweaned piglets
 
**Causes profuse [[Intestine Diarrhoea - Pathology|diarrhoea]]
 
 
 
*Very short 1 week prepatent period
 
 
 
*[[Intestine Diarrhoea - Pathology|Diarrhoea]] starts before oocysts are shed in faeces
 
**Ante-mortem diagnosis is difficult
 
 
 
*Death usually occurs after parasites have left the host
 
**Post-mortem diagnosis difficult
 
**''Isospora'' infections are '''self-limiting'''
 
 
 
==Coccidia of Dogs==
 
*2 common and 2 less common ''Isospora'' species
 
 
 
*Occasionally can cause disease
 
 
 
*Little pathogenicity
 
 
 
*Even if faecal oocyst count is high, other causes of [[Intestine Diarrhoea - Pathology|diarrhoea]] should be looked for
 
 
 
*''Hepatozoon americanum'' and subclinical ''H. canis'' in [[Bones Hyperplastic and Neoplastic - Pathology#Hepatozoon|periosteal bone formation]]
 
**Both are Tick borne diseases
 
***''H. canis'' – ''Rhipicephalus sanguineus''
 
***Ticks become infected by ingesting a blood meal containing macrophages and [[Neutrophils - WikiBlood|neutrophils]] infected with the parasite gamonts -> sexual replication in the gut of the tick -> oocysts containing infective sporozoites -> dogs ingest the tick  schizogony occurs in numerous tissues
 
 
 
==Coccidia of Cats==
 
*2 common ''Isospora'' species with little clinical significance
 
 
 
*Oocysts in faeces have to be distinguised from those of ''Toxoplasma'' (smaller) and ''Sarcocytis'' (sporulated or naked sporocyts in faeces)
 
 
 
==Coccidia of Rabbits==
 
*3 pathogenic ''Eimeria'' species
 
**2 in the [[Caecum - Anatomy & Physiology|caecum]]
 
**1 in the bile duct
 
 
 
*''Eimeria steidae''
 
**Parasitises the bile duct epithelium
 
**Travels via the bile duct to the [[Liver - Anatomy & Physiology|liver]] where it forms large white nodules
 
**Oocysts travel in the bile and are passed out in the faeces
 
**Causes ascites, [[Intestine Diarrhoea - Pathology|diarrhoea]], weight loss and polyuria
 
 
 
*Serious disease of both pet and farmed rabbits
 
 
 
*Treatment is by administration of drugs in drinking water
 
**E.g. Toltrazuril
 
 
 
*Hygiene is the best method of prevention to prevent sporocysts from sporulating
 
 
 
*Medicated feed can be used in commercial units
 
**E.g. Rabenidine
 
 
 
==[[Protozoa Flashcards - Wikibugs#Coccidia|Coccidia Flashcards]]==
 
[[Category:Coccidia]]
 

Latest revision as of 16:48, 20 May 2010

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