出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/10/10 14:09:48」(JST)
| This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (December 2009) |
| Eimeria tenella | |
|---|---|
| Scientific classification | |
| Kingdom: | Protista |
| Phylum: | Apicomplexa |
| Class: | Conoidasida |
| Order: | Eucoccidiorida |
| Family: | Eimeriidae |
| Genus: | Eimeria |
| Species: | E. tenella |
| Binomial name | |
| Eimeria tenella |
|
Eimeria tenella is a species of Eimeria that causes hemorrhagic cecal coccidiosis in young poultry.
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.
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.
There are two generations of schizonts and merozoites which are morphologycally distinguishable.
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.
The infected fowl passes out oocysts or zygocysts with faecal matter. When their oocysts are swallowed by a new or healthy bird, its digestive juices dissolve the cystwall and release sporozoites which enter the host epithelial cells. Within the epithelial cells, the sporozoites grow in size and multiply by schizogony.
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 contractile 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.
This protist-related article is a stub. You can help Wikipedia by expanding it.
|
This medical article is a stub. You can help Wikipedia by expanding it.
|
| 関連記事 | 「Eimeria」 |