Difference between revisions of "Coccidia"

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#REDIRECT[[:Category:Coccidia]]
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==Introduction==
 +
 
 +
[[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]]
 +
 
 +
 
 +
===Coccidia of Game Birds===
 +
*3 main species
 +
 
 +
*[[Caecum - Anatomy & Physiology|Caecal]] species most pathogenic causing white [[Caecum - Anatomy & Physiology|caecal]] cores
 +
 
 +
==Coccidia of Cattle==
 +
[[Image:Coccidia ruminant.jpg|thumb|right|150px|''Eimeria'' sp. of ruminants - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 +
[[Image:Coccidia oocyst ruminant.jpg|thumb|right|150px|Coccidia oocyst from ruminant faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 +
*Many species affect cattle
 +
 
 +
*Cattle under a year old are usually infected sporadically
 +
 
 +
*2-3 week prepatent period
 +
 
 +
*''Eimeria bovis''
 +
**Endogenous stages in central lacteal of villi and epithelial cells of [[Caecum - Anatomy & Physiology|caecum]] and [[Colon - Anatomy & Physiology|colon]]
 +
**Causes [[Intestine Diarrhoea - Pathology|diarrhoea]] and enteritis
 +
**Oocysts are 28x20μm
 +
**Moderately pathogenic
 +
 
 +
*''Eimeria zuernii''
 +
**Endogenous stages in connective tissue of lamina propria of the lower [[Small Intestine - Anatomy & Physiology|small intestine]] and in the epithelial cells of the [[Caecum - Anatomy & Physiology|caecum]] and [[Colon - Anatomy & Physiology|colon]]
 +
**More pathogenic than ''Eimeria bovis''
 +
**Causes blood stained dysentery, tenesmus and sloughed mucosa
 +
**Oocysts are spherical and measure 16μm
 +
 
 +
*Mainly occurs in calves in poor conditions and bought-in calves
 +
**Also occurs in suckler calves turned out in spring
 +
 
 +
*''Eimeria alabamensis'' associated with [[Intestine Diarrhoea - Pathology|diarrhoea]] in calves after spring turnout
 +
 
 +
*[[Materno-fetal immunity - WikiBlood#Passive transfer via colostrum|Passive immunity]] is sufficient during the neonatal period
 +
 
 +
*Can be concurrent with cryptosporidium, viral and bacterial agents
 +
 
 +
'''Diagnosis'''
 +
*History, clinical signs, [[Intestine Diarrhoea - Pathology|diarrhoea]] (often with blood) and a decrease in weight gain
 +
 
 +
*Post-mortem
 +
**Diffuse inflammation and thickening of [[Caecum - Anatomy & Physiology|caecal]] mucosa (and sometimes [[Ileum - Anatomy & Physiology|ileal]] and [[Colon - Anatomy & Physiology|colonic]] mucosa)
 +
**Masses of gamonts and oocysts in scrapings
 +
 
 +
*High faecal oocyst count
 +
**However, healthy animals can pass millions of oocysts from mixed species infections which have no pathogenic significance
 +
**Animals may die before oocysts are shed
 +
 
 +
'''Control'''
 +
*Improve husbandry
 +
**Improve sanitation
 +
**Increase bedding
 +
**Raise food and water troughs to avoid faecal contamination
 +
 
 +
*Preventative in-feed medication
 +
**E.g. Decoquinate
 +
 
 +
*Injectable antiprotozoals may limit oocyst production but animals should still be moved to a clean environment
 +
**E.g. Sulphamethoxypyridazine
 +
 
 +
==Coccidia of Sheep==
 +
[[Image:Isospora felis sporulated.jpg|thumb|right|150px|''Isospora felis'' sporulated - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
 +
[[Image:Isospora felis unsporulated.jpg|thumb|right|150px|''Isospora felis'' unsporulated - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
 +
*11 different Coccidia species although only two are of clinical significance
 +
**Giant schizonts visible as white spots
 +
 
 +
*''Eimeria ovinoidalis''
 +
**Highly pathogenic
 +
**[[Intestine Diarrhoea - Pathology|Diarrhoea]]
 +
**Parasitises the [[Caecum - Anatomy & Physiology|caecum]] and [[Colon - Anatomy & Physiology|colon]]
 +
 
 +
*''Eimeria crandalis''
 +
**Varying pathogenicity
 +
**Scours, grey, foul-smelling faeces
 +
**Parasitises the [[Small Intestine - Anatomy & Physiology|small intestine]], [[Caecum - Anatomy & Physiology|caecum]] and [[Colon - Anatomy & Physiology|colon]]
 +
 
 +
*2 week prepatent period
 +
 
 +
*Disease frequently seen in lambs under 6 months old
 +
**More often in twins and triplets when single lambs
 +
 
 +
*Oocyts from ewes (immune carriers) accumulate in poorly managed litter or around feed and water troughs
 +
 
 +
*Lambs born early in the year amplify the parasite problem increasing the parasite risk to lambs born later in the year
 +
 
 +
*Affected lambs may die before oocysts are found in the faeces
 +
**Post-mortem diagnosis difficult
 +
 
 +
*Different species of ''Eimeria'' occurs in sheep and goats
 +
 
 +
*Infection may be coincident with ''Neospora'' or ''Cryptosporidium'' infections
 +
**Mixed infections complicate the diagnosis as oocyst differentiation is difficult
 +
 
 +
*Other non-pathogenic species can cause papillomatous mucosal growths
 +
 
 +
'''Control'''
 +
*Improve husbandry
 +
**Avoid overcrowding
 +
**Decrease stress
 +
 
 +
*Improve hygiene by dagging ewes
 +
 
 +
*Avoid mixing lambs of different ages
 +
 
 +
*Preventative measures include creep feeding lambs with decoquinate or oral dosing with diclazuril when lambs are 4-6 weeks
 +
**A second dose can be given after 3 weeks
 +
 
 +
==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]]

Revision as of 21:51, 8 April 2010

Introduction

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

Eimeria spp.

Isospora spp.

Coccidiosis

Coccidia of Poultry

Coccidiosis - Poultry

Coccidia of Turkeys

Coccidia of Geese

Coccidia of Ducks


Coccidia of Game Birds

  • 3 main species

Coccidia of Cattle

Eimeria sp. of ruminants - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
Coccidia oocyst from ruminant faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
  • Many species affect cattle
  • Cattle under a year old are usually infected sporadically
  • 2-3 week prepatent period
  • Eimeria bovis
    • Endogenous stages in central lacteal of villi and epithelial cells of caecum and colon
    • Causes diarrhoea and enteritis
    • Oocysts are 28x20μm
    • Moderately pathogenic
  • Eimeria zuernii
    • Endogenous stages in connective tissue of lamina propria of the lower small intestine and in the epithelial cells of the caecum and colon
    • More pathogenic than Eimeria bovis
    • Causes blood stained dysentery, tenesmus and sloughed mucosa
    • Oocysts are spherical and measure 16μm
  • Mainly occurs in calves in poor conditions and bought-in calves
    • Also occurs in suckler calves turned out in spring
  • Eimeria alabamensis associated with diarrhoea in calves after spring turnout
  • Can be concurrent with cryptosporidium, viral and bacterial agents

Diagnosis

  • History, clinical signs, diarrhoea (often with blood) and a decrease in weight gain
  • Post-mortem
    • Diffuse inflammation and thickening of caecal mucosa (and sometimes ileal and colonic mucosa)
    • Masses of gamonts and oocysts in scrapings
  • High faecal oocyst count
    • However, healthy animals can pass millions of oocysts from mixed species infections which have no pathogenic significance
    • Animals may die before oocysts are shed

Control

  • Improve husbandry
    • Improve sanitation
    • Increase bedding
    • Raise food and water troughs to avoid faecal contamination
  • Preventative in-feed medication
    • E.g. Decoquinate
  • Injectable antiprotozoals may limit oocyst production but animals should still be moved to a clean environment
    • E.g. Sulphamethoxypyridazine

Coccidia of Sheep

Isospora felis sporulated - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine
Isospora felis unsporulated - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine
  • 11 different Coccidia species although only two are of clinical significance
    • Giant schizonts visible as white spots
  • 2 week prepatent period
  • Disease frequently seen in lambs under 6 months old
    • More often in twins and triplets when single lambs
  • Oocyts from ewes (immune carriers) accumulate in poorly managed litter or around feed and water troughs
  • Lambs born early in the year amplify the parasite problem increasing the parasite risk to lambs born later in the year
  • Affected lambs may die before oocysts are found in the faeces
    • Post-mortem diagnosis difficult
  • Different species of Eimeria occurs in sheep and goats
  • Infection may be coincident with Neospora or Cryptosporidium infections
    • Mixed infections complicate the diagnosis as oocyst differentiation is difficult
  • Other non-pathogenic species can cause papillomatous mucosal growths

Control

  • Improve husbandry
    • Avoid overcrowding
    • Decrease stress
  • Improve hygiene by dagging ewes
  • Avoid mixing lambs of different ages
  • Preventative measures include creep feeding lambs with decoquinate or oral dosing with diclazuril when lambs are 4-6 weeks
    • A second dose can be given after 3 weeks

Coccidia of Goats

Goats - nabrown RVC
Eimeria leukarti - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
Isospora suis oocyst from pig faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
Isospora canis - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
Coccidia in Cat Faeces - Joel Mills
Isospora felis - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
  • Many Eimeria species
  • 2 Eimeria are pathogenic
  • 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
  • Besnoitia bennetti in 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
  • Very short 1 week prepatent period
  • 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 diarrhoea should be looked for
  • Hepatozoon americanum and subclinical H. canis in periosteal bone formation
    • Both are Tick borne diseases
      • H. canisRhipicephalus sanguineus
      • Ticks become infected by ingesting a blood meal containing macrophages and 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
    • 1 in the bile duct
  • Eimeria steidae
    • Parasitises the bile duct epithelium
    • Travels via the bile duct to the liver where it forms large white nodules
    • Oocysts travel in the bile and are passed out in the faeces
    • Causes ascites, 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

Coccidia Flashcards