Difference between revisions of "Coccidia"
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**Endogenous stages in central lacteal of villi and epithelial cells of caecum and colon | **Endogenous stages in central lacteal of villi and epithelial cells of caecum and colon | ||
**Causes [[Intestine Diarrhoea - Pathology|diarrhoea]] and enteritis | **Causes [[Intestine Diarrhoea - Pathology|diarrhoea]] and enteritis | ||
− | **Oocysts are | + | **Oocysts are 28x20μm |
+ | **Moderately pathogenic | ||
*''Eimeria zuernii'' | *''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 dysentry, tenesmus and sloughed mucosa | ||
+ | **Oocysts are spherical and measure 16μm | ||
*Mainly occurs in calves in poor conditions and brought-in calves | *Mainly occurs in calves in poor conditions and brought-in calves |
Revision as of 21:35, 15 November 2008
This article is still under construction. |
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Eimeria spp.
Isospora spp.
Coccidia of Poultry
Other Avian Coccidia
Coccidia of Cattle
- 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 dysentry, tenesmus and sloughed mucosa
- Oocysts are spherical and measure 16μm
- Mainly occurs in calves in poor conditions and brought-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
- 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 faecal and water troughs to avoid faecal contamination
- Preventative in-feed medication
- E.g. Decoquinate
- Injectible 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 Eiemria
- 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
- 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