Difference between revisions of "Coccidia"
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− | # | + | [[Coccidiosis]] |
+ | |||
+ | ==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 | ||
+ | [[Eimeria spp.|''Eimeria'' spp.]] | ||
+ | |||
+ | |||
+ | [[Isospora spp.|''Isospora'' spp.]] | ||
+ | |||
+ | |||
+ | [[Coccidia - Poultry]] | ||
+ | |||
+ | [[Coccidiosis - 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 | ||
+ | |||
+ | ==Other Avian Coccidia== | ||
+ | ===Coccidia of Turkeys=== | ||
+ | |||
+ | *5 ''Eimeria'' species | ||
+ | **2 important pathogenically | ||
+ | |||
+ | *''Eimeria'' in [[Caecum - Anatomy & Physiology|caeca]] causes petechial haemorrhages and caseous [[Caecum - Anatomy & Physiology|caecal]] cores | ||
+ | |||
+ | *''Eimeria'' in the anterior and mid-intestine causes necrotic enteritis and petechial haemorrhages | ||
+ | |||
+ | *Causes watery [[Intestine Diarrhoea - Pathology|diarrhoea]] in young poults and some mortality | ||
+ | |||
+ | ===Coccidia of Geese=== | ||
+ | *3 ''Eimeria'' species | ||
+ | |||
+ | *2 intestinal species causing macroscopic lesions in [[Urinary System - Anatomy & Physiology#The Kidney|kidney tubules]] | ||
+ | **Oocysts carried in urine and pass out with faeces | ||
+ | |||
+ | *Renal species cause severe disease in goslings | ||
+ | **Depression, emaciation, [[Intestine Diarrhoea - Pathology|diarrhoea]] and sometimes death | ||
+ | |||
+ | ===Coccidia of Ducks=== | ||
+ | [[Image:Crested duck.jpg|thumb|right|150px|Crested duck - nabrown RVC]] | ||
+ | *Several ''Eimeria'' species | ||
+ | |||
+ | *Another coccidia species which produces 8 sporozoites but these are not enclosed in a sporocyst | ||
+ | |||
+ | *Causes severe enteritis and mortality in ducklings | ||
+ | **Haemorrhages and pale focal lesions in [[Small Intestine - Anatomy & Physiology|small intestine]] | ||
+ | |||
+ | ===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 21:42, 8 April 2010
Introduction
- 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
Coccidiosis - 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 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
Other Avian Coccidia
Coccidia of Turkeys
- 5 Eimeria species
- 2 important pathogenically
- Eimeria in the anterior and mid-intestine causes necrotic enteritis and petechial haemorrhages
- Causes watery diarrhoea in young poults and some mortality
Coccidia of Geese
- 3 Eimeria species
- 2 intestinal species causing macroscopic lesions in kidney tubules
- Oocysts carried in urine and pass out with faeces
- Renal species cause severe disease in goslings
- Depression, emaciation, diarrhoea and sometimes death
Coccidia of Ducks
- Several Eimeria species
- Another coccidia species which produces 8 sporozoites but these are not enclosed in a sporocyst
- Causes severe enteritis and mortality in ducklings
- Haemorrhages and pale focal lesions in small intestine
Coccidia of Game Birds
- 3 main species
Coccidia of Cattle
- Many species affect cattle
- Cattle under a year old are usually infected sporadically
- 2-3 week prepatent period
- Eimeria bovis
- 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
- Passive immunity is sufficient during the neonatal period
- 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
- 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
- 11 different Coccidia species although only two are of clinical significance
- Giant schizonts visible as white spots
- Eimeria crandalis
- Varying pathogenicity
- Scours, grey, foul-smelling faeces
- Parasitises the small intestine, caecum and 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
- Many Eimeria species
- 2 Eimeria are pathogenic
- Cause 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 diarrhoea
- 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
- Causes profuse diarrhoea
- 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. canis – Rhipicephalus 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
- Both are Tick borne diseases
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
- 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