Eimeria tenella is a species of Eimeria that causes hemorrhagic cecal coccidiosis in young poultry.
| Eimeria tenella | |
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| Species: | E. tenella
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| Eimeria tenella | |
Description
This species has a monoxeous life cycle with the definitive (only) host as chickens; it is extremely host-specific. Acquired via fecal contamination of food and water (oral-fecal route), it undergoes endogenous merogony in the crypts of Lieberkuhr (intestinal ceca of chicken) and gametogony in epithelial cells of the small intestines. Fusion of microgamete and macrogamete forms results in unsporulated zygotes, which are released with feces of chicken. The zygote sporulates after one to five days, and becomes infective.
Diagnosis is based on finding oocysts in feces. While no effective treatment exists, the rate of infection can be reduced via prophylates, anticoccidial drugs and vaccination of baby chicks.
Life Cycle
Eimeria tenella is monogenetic. Various stages of complicated life cycle may conveniently be described under two phases, asexual cycle or schizogony and sexual cycle involving gametogony. Much of life cycle is intracellular.
Schizogony
There are two generations of schizonts and merozoites which are morphologycally distinguishable.
First generation schizogony
The beginning of complex life cycle of Eimeria tenella may be taken to be initiated by infection of epithelial cells of host caecum by sporozoites.
Infection by sporozoites
The infected fowl passes out oocysts or zygocysts with faecal matter. When there oocysts are swallowed by a new or healthy bird, its digestive juices dissolve the cystwall and release sporozoites which enter the hut epithelial cells. Within the epithelial cells, the sporozoites grow in size and multiply by schizogony.
Sporozoite
It is the earliest intracellular stage of parasite. It is elongated, slightly curved, microscopic unicellular organism with one end pointed and the other end blunt. The pellicle, forming external envelope, contains longitudinally arranged contractike microtubules which help in wriggling movements of organism. Cytoplasm includes a vesicular nucleus, a mitochondrion, golgi bodies, endoplasmic reticulum, ribosomes, lysosomes and vacuoles containing reserve food, etc. Penetration of sporozoite into host epithelial cell is facilitated by the lytic secretion stored in roptries of parasite.
Bibliography
- Transclusion error: {{En}} is only for use in File namespace. Use {{langx|en}} or {{in lang|en}} instead. R.L. KOTPAL (2006)
- Transclusion error: {{En}} is only for use in File namespace. Use {{langx|en}} or {{in lang|en}} instead. RL Stotish & al. (1976), http://www.jbc.org/content/251/2/302.full.pdf Studies of a glycoprotein in the oocysts of Eimeria tenella]. ; Journal of Biological chemistry, vol 251, n°2, 25 janv 1976, pp 302 à 507
