3. Coccidia Coccidiosis of chicken, geese Flashcards
Is coccidiosis caused by one genus of protozoal parasites?
No. Mainly Eimeria genus but also Isospora, Cycloisospora
Eimeria is stenoxen and hemoxen, what does it mean?
Stenoxen - host range is very narrow. Usually specific to one host
Hemoxen - full life-cycle is completed in one host
Prepatent period
Period between infection with a parasite and detection of oocyst
Lyfe cycle of Eimeria species
- Unsporulated oocysts (in feces of infected animals, non-infectious stage) -›
- Sporulation in outside world (temperature, humidity, oxygen) -› becoming infectious (!)
- Sporulated oocysts will be consumed by animals -› animals get infected -›
- Inside of the body (temperature, pH, CO2, intestinal fluids) sporozoites get free from oocysts penetrating cells of the host
- Asexual development: schizogony
- Sexual development: gametogony (microgametocytes, macrogametocytes
Schizogony - ?
Asexual development of Eimeria species. Sporozoites -› Trophozoit -› Shizont -› Merozoits. Host cells will be destroyed.
Schizogony repeats several times (usuallly 2-6 times). Lasts usually 2-3 days.
?
Schizonts of Eimeria spp. Coccidiosis
(can be in midterm!!)
Gametogony
Sexual development. Microgametocystes + macrogametocytes -› macrogamonts.
Result of gametogony: oocysts
Oocysts in different stainings:
- Giemsa: stay white - not used for oocysts
- Iodine (everythyng yellow) - not used for oocysts
- Kinyoun staining - oocysts will be red, everything else is bluish
Parasites causing coccidiosis in chicken by pathogenicity:
STRONGLY PATHOGENIC:
- Eimeria necatrix
- Eimeria tenella
- Eimeria brunetti
Moderately pathogenic:
- Eimeria maxima
Weakly pathogenic:
- E. mitis
- E. acervulina
- E. praecox
Coccidiosis in duodenum of chicken
2 weakly pathogenic species: E. acervulina and E. praecox
E. acervulina: discrete white foci - PP: 4-5 days
E. praecox: usually no macroscopic lesions ‹ 4 days
Coccidiosis in jejunum of chicken (strongly pathogenic one)
E. necatrix
Haemorrhagic enteritis. White spots -› “salt and pepper”
PP: 6-7 days (usually during this period already kills the chicken)
Coccidiosis in jejunum of chicken (moderately pathogenic one)
E. maxima
Petechial haemorrhage, catarrhal imflammation
Large schizonts nests (whitish dots)
PP: 5-6 days
Coccidiosis of distal part of jejunum and ileum in chicken?
E. mitis
Coccidiosis in caeca of chicken:
E. tenella - strongly pathogenic species
Extensive haemorrhage, deep erosion of epithelium, partially clotted or clotted blood in the lumen
PP: 6-7 days
Coccidiosis in lower small intestine. caeca, colon, rectum, cloaca
E. brunetti - srongly pathogenic species
PP: 5 days
haemorrhagic, catarrhal exsudate and coagulative necrosisof the mucosal surface
Coccidiosis in geese. Forms.
- Intestinal coccidiosis: E. anseris, E. nocens
- Renal coccidiosis: E. truncata - greyish white foci
for midterm only E. truncata is important
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Kidney -› only E. truncata is in the kidney. Gametogony
