Difference between revisions of "Tissue cyst-forming coccidia"

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#REDIRECT[[:Category:Tissue Cyst Forming Coccidia]]
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==Toxoplasma==
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*1 major pathogenic species called ''Toxoplasma gondii''
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*Causes disease in a wide range of animal species including humans
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*Important cause of abortion in sheep
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*Zoonotic
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**Can cause abortion
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**Can cause congenitally aquired defects
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*Forms a sporulated oocyst which is only 10μm
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**Contains 2 sporocysts with 4 sporozoites
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*Transmission through ingesting the intermediate host or via the faecal-oral route
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'''Life Cycle'''
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*Complex
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*Usually indirect
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*Gametogeny (sexual stage) is host specific for felids
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*Any warm blooded animal can act as a facultative intermediate host
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**Asexual reproduction occurs in the intermediate host forming tissue cysts
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**Intermediate host swallows sporulated oocysts or tissue cysts
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**Can be transferred between intermediate hosts by carnivorism
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Toxoplasma can cause [[Pancreas Inflammatory - Pathology#Acute haemorrhagic pancreatitis|acute interstitial pancreatitis]] in systemic toxoplasmosis
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*''T. gondii'' in [[Respiratory Parasitic Infections - Pathology#Toxoplasmosis|pneumonia]]
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*''Toxoplasma gondii'', ''Sarcocystis'' and ''Neospora caninum'' in [[Muscles Inflammatory - Pathology#Protozoa|myositis]]
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==Sarcocystis==
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*Most infections are asymptomatic
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*Heavy infections are causes of chronic wasting in large animals, hide sondemnation and downgrading of carcasses
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*''Sarcocystis'' should be differentiated from other tissue-cyst forming coccidia
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*There are many species of ''Sarcocystis''
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*Sporulated oocyst has 2 sporocysts containing 4 sporozoites
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**Naked oocyst usually seen in faeces as the oocyst wall is very delicate
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*Indirect life cycle
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*Life cycle alternates between the final and the obligatory intermediate host
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*Only one final and one intermediate host
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==Neospora==
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*2 main species
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**''Neospora caninum'' in the dog
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**''Neospora hughesi'' in the horse
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*Sporulated oocysts measuring just 10μm
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*Oocyst contains 2 sporocysts with 4 sporozoites
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*Life cycle similar to ''Toxoplasma gondii''
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*Limited range of warm-blooded intermediate hosts
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**Asexual reproduction occurs in intermediate host forming tissue cysts
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*Host range of sexual stage is unknown for ''N.caninum''
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**Intermediate host for ''N.hughesi'' is the horse, but the definitive host is unknown
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*Route of transmission not fully understood

Revision as of 09:04, 17 November 2008



Infectious agents and parasitesWikiBugs Banner.png
PARASITES
PROTOZOA



Toxoplasma

  • 1 major pathogenic species called Toxoplasma gondii
  • Causes disease in a wide range of animal species including humans
  • Important cause of abortion in sheep
  • Zoonotic
    • Can cause abortion
    • Can cause congenitally aquired defects
  • Forms a sporulated oocyst which is only 10μm
    • Contains 2 sporocysts with 4 sporozoites
  • Transmission through ingesting the intermediate host or via the faecal-oral route

Life Cycle

  • Complex
  • Usually indirect
  • Gametogeny (sexual stage) is host specific for felids
  • Any warm blooded animal can act as a facultative intermediate host
    • Asexual reproduction occurs in the intermediate host forming tissue cysts
    • Intermediate host swallows sporulated oocysts or tissue cysts
    • Can be transferred between intermediate hosts by carnivorism

Toxoplasma can cause acute interstitial pancreatitis in systemic toxoplasmosis

  • T. gondii in pneumonia
  • Toxoplasma gondii, Sarcocystis and Neospora caninum in myositis

Sarcocystis

  • Most infections are asymptomatic
  • Heavy infections are causes of chronic wasting in large animals, hide sondemnation and downgrading of carcasses
  • Sarcocystis should be differentiated from other tissue-cyst forming coccidia
  • There are many species of Sarcocystis
  • Sporulated oocyst has 2 sporocysts containing 4 sporozoites
    • Naked oocyst usually seen in faeces as the oocyst wall is very delicate
  • Indirect life cycle
  • Life cycle alternates between the final and the obligatory intermediate host
  • Only one final and one intermediate host

Neospora

  • 2 main species
    • Neospora caninum in the dog
    • Neospora hughesi in the horse
  • Sporulated oocysts measuring just 10μm
  • Oocyst contains 2 sporocysts with 4 sporozoites
  • Life cycle similar to Toxoplasma gondii
  • Limited range of warm-blooded intermediate hosts
    • Asexual reproduction occurs in intermediate host forming tissue cysts
  • Host range of sexual stage is unknown for N.caninum
    • Intermediate host for N.hughesi is the horse, but the definitive host is unknown
  • Route of transmission not fully understood