Difference between revisions of "Coccidiosis - Poultry"
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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''…') |
m (Text replace - 'Eimeria' to 'Eimeria') |
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| Line 2: | Line 2: | ||
'''Pathogenesis''' | '''Pathogenesis''' | ||
| − | *7 important ''Eimeria'' species | + | *7 important ''[[Eimeria spp.|Eimeria]]'' species |
*4 malabsorptive species | *4 malabsorptive species | ||
| − | **''Eimeria acervulina'' which is moderately pathogenic | + | **''[[Eimeria spp.|Eimeria]] acervulina'' which is moderately pathogenic |
| − | **''Eimeria maxima'' which is moderately pathogenic | + | **''[[Eimeria spp.|Eimeria]] maxima'' which is moderately pathogenic |
| − | **''Eimeria mitis'' which has low pathogenicity | + | **''[[Eimeria spp.|Eimeria]] mitis'' which has low pathogenicity |
| − | **''Eimeria praecox'' which has low pathogenicity | + | **''[[Eimeria spp.|Eimeria]] praecox'' which has low pathogenicity |
*3 haemorrhagic species | *3 haemorrhagic species | ||
| − | **''Eimeria tenella'' | + | **''[[Eimeria spp.|Eimeria]] tenella'' |
| − | **''Eimeria necatrix'' | + | **''[[Eimeria spp.|Eimeria]] necatrix'' |
| − | **''Eimeria brunetti'' | + | **''[[Eimeria spp.|Eimeria]] brunetti'' |
**All highly pathogenic | **All highly pathogenic | ||
**Form large sub-epithelial second generation schizonts at the base of intestinal crypts | **Form large sub-epithelial second generation schizonts at the base of intestinal crypts | ||
| Line 28: | Line 28: | ||
**Size of schizonts and oocysts found in mucosal scrapings | **Size of schizonts and oocysts found in mucosal scrapings | ||
| − | *''Eimeria acervulina'' | + | *''[[Eimeria spp.|Eimeria]] acervulina'' |
**Proximal gut | **Proximal gut | ||
**Thickening of walls | **Thickening of walls | ||
| Line 34: | Line 34: | ||
**Watery exudate | **Watery exudate | ||
| − | *''Eimeria maxima'' | + | *''[[Eimeria spp.|Eimeria]] maxima'' |
**Mid-gut | **Mid-gut | ||
**Thickening of walls | **Thickening of walls | ||
**Pink exudate | **Pink exudate | ||
| − | *''Eimeria tenella'' | + | *''[[Eimeria spp.|Eimeria]] tenella'' |
**Swollen [[Caecum - Anatomy & Physiology|caeca]] | **Swollen [[Caecum - Anatomy & Physiology|caeca]] | ||
**Thickening of wall | **Thickening of wall | ||
**Dark colouring containing a core of necrotic tissue and blood | **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 | + | *Lesion scoring is the best method of diagnosing the severity of the lesions and therefore the causative ''[[Eimeria spp.|Eimeria]]'' species |
| − | *''Eimeria necatrix'' | + | *''[[Eimeria spp.|Eimeria]] necatrix'' |
**Mid-gut | **Mid-gut | ||
**Ballooning of wall | **Ballooning of wall | ||
| Line 53: | Line 53: | ||
'''Immunity''' | '''Immunity''' | ||
| − | *Different ''Eimeria'' species produce different levels of protective immunity | + | *Different ''[[Eimeria spp.|Eimeria]]'' species produce different levels of protective immunity |
**''E.maxima'' -> ''E.brunetti'' and ''E.acervulina'' -> ''E.tenella'' and ''E.necatrix'' | **''E.maxima'' -> ''E.brunetti'' and ''E.acervulina'' -> ''E.tenella'' and ''E.necatrix'' | ||
| Line 86: | Line 86: | ||
**Paracox | **Paracox | ||
***Multivalent attenuated [[Vaccines - WikiBlood#What antigen(s) do we use in the vaccine?|live vaccine]] for replacement layers and broilers | ***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'' | + | ***Contains 7 live strains of ''[[Eimeria spp.|Eimeria]]'' |
***Lack the most pathogenic life cycle stage making the prepatent period shorter | ***Lack the most pathogenic life cycle stage making the prepatent period shorter | ||
***Known as '''precocious''' strains | ***Known as '''precocious''' strains | ||
| Line 92: | Line 92: | ||
***[[Vaccines - WikiBlood|Vaccinated]] birds have sub-optimal growth rates so is not used for broilers | ***[[Vaccines - WikiBlood|Vaccinated]] birds have sub-optimal growth rates so is not used for broilers | ||
**Paracox 5 | **Paracox 5 | ||
| − | ***Contains 5 strains of the most pathogenic ''Eimeria'' | + | ***Contains 5 strains of the most pathogenic ''[[Eimeria spp.|Eimeria]]'' |
***Used for broilers | ***Used for broilers | ||
***Sprayed onto the first feed offered to new batches of chicks | ***Sprayed onto the first feed offered to new batches of chicks | ||
Revision as of 22:51, 8 April 2010
Pathogenesis
- 7 important Eimeria species
- 4 malabsorptive species
- 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 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 here
- Vaccines
- Paracox
- Multivalent attenuated 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 vaccinated on a single occasion when 1-9 days old through oocyst suspension in the feed or water
- 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
- Paracox
- Integrated control
- Careful management is needed so in-feed prophylaxis and 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