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Created page with 'Coccidia - Poultry '''Pathogenesis''' *7 important ''Eimeria'' species *4 malabsorptive species **''Eimeria acervulina'' which is moderately pathogenic **''Eimeria maxima''…'
[[Coccidia - Poultry]]
'''Pathogenesis'''
*7 important ''Eimeria'' species
*4 malabsorptive species
**''Eimeria acervulina'' which is moderately pathogenic
**''Eimeria maxima'' which is moderately pathogenic
**''Eimeria mitis'' which has low pathogenicity
**''Eimeria praecox'' which has low pathogenicity
*3 haemorrhagic species
**''Eimeria tenella''
**''Eimeria necatrix''
**''Eimeria brunetti''
**All highly pathogenic
**Form large sub-epithelial second generation schizonts at the base of intestinal crypts
**Deep eruptions form when cells rupture to release merozoites
**Destruction of crypt stem cells and marked haemorrhage
**Blood stained faeces
**High morbidity and high mortality
'''Diagnosis'''
*Post-mortem diagnosis of lesion severity
**Region of intestine affected
**Appearance of lesion
**Presence or absence of haemorrhage
**Size of schizonts and oocysts found in mucosal scrapings
*''Eimeria acervulina''
**Proximal gut
**Thickening of walls
**'White ladder lesions' produced by dense foci of gamonts and oocysts
**Watery exudate
*''Eimeria maxima''
**Mid-gut
**Thickening of walls
**Pink exudate
*''Eimeria tenella''
**Swollen [[Caecum - Anatomy & Physiology|caeca]]
**Thickening of wall
**Dark colouring containing a core of necrotic tissue and blood
*Lesion scoring is the best method of diagnosing the severity of the lesions and therefore the causative ''Eimeria'' species
*''Eimeria necatrix''
**Mid-gut
**Ballooning of wall
**White spots and petechiae forming 'salt and pepper' lesions
**Haemorrhage into lumen
'''Immunity'''
*Different ''Eimeria'' species produce different levels of protective immunity
**''E.maxima'' -> ''E.brunetti'' and ''E.acervulina'' -> ''E.tenella'' and ''E.necatrix''
*There is no cross immunity between species
*There is very little passive immunity
*Evokes a cell-mediated response
*All ages of poultry are susceptible
'''Epidemiology'''
*Oocysts are ubiquitous and robust
**Able to survive several months to years
*It is impossible to keep buildings free from infection
**Chicks become infected by pecking the ground shortly after being placed in the poultry house
*Biotic potential is enormous
**Generation time is short
**Massive infections can build up rapidly
*Immunity develops relatively slowly
**With high stocking densities the situation is explosive
'''Control'''
*Chemical
**Intensive poultry production is largely dependent on the use of anticoccidial drugs
**For more information see [[Anti-Protozoal Drugs|here]]
*[[Vaccines - WikiBlood|Vaccines]]
**Paracox
***Multivalent attenuated [[Vaccines - WikiBlood#What antigen(s) do we use in the vaccine?|live vaccine]] for replacement layers and broilers
***Contains 7 live strains of ''Eimeria''
***Lack the most pathogenic life cycle stage making the prepatent period shorter
***Known as '''precocious''' strains
***Chicks [[Vaccines - WikiBlood|vaccinated]] on a single occasion when 1-9 days old through oocyst suspension in the feed or water
***[[Vaccines - WikiBlood|Vaccinated]] birds have sub-optimal growth rates so is not used for broilers
**Paracox 5
***Contains 5 strains of the most pathogenic ''Eimeria''
***Used for broilers
***Sprayed onto the first feed offered to new batches of chicks
*Integrated control
**Careful management is needed so in-feed prophylaxis and [[Vaccines - WikiBlood|vaccination]] do not fail
**Remove litter and thoroughly clean houses in between crops
***Optimum turn-around time is 10 days
**Use the lowest stocking density which is compatible with economic production
**Water bowls, roofs and walls should be well maintained to prevent litter becoming damp
**Stress factors should be avoided and adequate nutrition provided[[Category:Coccidia]][[Category:Poultry]]
'''Pathogenesis'''
*7 important ''Eimeria'' species
*4 malabsorptive species
**''Eimeria acervulina'' which is moderately pathogenic
**''Eimeria maxima'' which is moderately pathogenic
**''Eimeria mitis'' which has low pathogenicity
**''Eimeria praecox'' which has low pathogenicity
*3 haemorrhagic species
**''Eimeria tenella''
**''Eimeria necatrix''
**''Eimeria brunetti''
**All highly pathogenic
**Form large sub-epithelial second generation schizonts at the base of intestinal crypts
**Deep eruptions form when cells rupture to release merozoites
**Destruction of crypt stem cells and marked haemorrhage
**Blood stained faeces
**High morbidity and high mortality
'''Diagnosis'''
*Post-mortem diagnosis of lesion severity
**Region of intestine affected
**Appearance of lesion
**Presence or absence of haemorrhage
**Size of schizonts and oocysts found in mucosal scrapings
*''Eimeria acervulina''
**Proximal gut
**Thickening of walls
**'White ladder lesions' produced by dense foci of gamonts and oocysts
**Watery exudate
*''Eimeria maxima''
**Mid-gut
**Thickening of walls
**Pink exudate
*''Eimeria tenella''
**Swollen [[Caecum - Anatomy & Physiology|caeca]]
**Thickening of wall
**Dark colouring containing a core of necrotic tissue and blood
*Lesion scoring is the best method of diagnosing the severity of the lesions and therefore the causative ''Eimeria'' species
*''Eimeria necatrix''
**Mid-gut
**Ballooning of wall
**White spots and petechiae forming 'salt and pepper' lesions
**Haemorrhage into lumen
'''Immunity'''
*Different ''Eimeria'' species produce different levels of protective immunity
**''E.maxima'' -> ''E.brunetti'' and ''E.acervulina'' -> ''E.tenella'' and ''E.necatrix''
*There is no cross immunity between species
*There is very little passive immunity
*Evokes a cell-mediated response
*All ages of poultry are susceptible
'''Epidemiology'''
*Oocysts are ubiquitous and robust
**Able to survive several months to years
*It is impossible to keep buildings free from infection
**Chicks become infected by pecking the ground shortly after being placed in the poultry house
*Biotic potential is enormous
**Generation time is short
**Massive infections can build up rapidly
*Immunity develops relatively slowly
**With high stocking densities the situation is explosive
'''Control'''
*Chemical
**Intensive poultry production is largely dependent on the use of anticoccidial drugs
**For more information see [[Anti-Protozoal Drugs|here]]
*[[Vaccines - WikiBlood|Vaccines]]
**Paracox
***Multivalent attenuated [[Vaccines - WikiBlood#What antigen(s) do we use in the vaccine?|live vaccine]] for replacement layers and broilers
***Contains 7 live strains of ''Eimeria''
***Lack the most pathogenic life cycle stage making the prepatent period shorter
***Known as '''precocious''' strains
***Chicks [[Vaccines - WikiBlood|vaccinated]] on a single occasion when 1-9 days old through oocyst suspension in the feed or water
***[[Vaccines - WikiBlood|Vaccinated]] birds have sub-optimal growth rates so is not used for broilers
**Paracox 5
***Contains 5 strains of the most pathogenic ''Eimeria''
***Used for broilers
***Sprayed onto the first feed offered to new batches of chicks
*Integrated control
**Careful management is needed so in-feed prophylaxis and [[Vaccines - WikiBlood|vaccination]] do not fail
**Remove litter and thoroughly clean houses in between crops
***Optimum turn-around time is 10 days
**Use the lowest stocking density which is compatible with economic production
**Water bowls, roofs and walls should be well maintained to prevent litter becoming damp
**Stress factors should be avoided and adequate nutrition provided[[Category:Coccidia]][[Category:Poultry]]