Difference between revisions of "Coccidia Life Cycle"
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Coccidia belong to the phylum Apicomplexa and are protozoan parasites of mammals, birds and reptiles. Coccidia have three major stages to their life cycle: Sporogony, Schizogony, Gametogony. The first two stages are asexual, with sexual reproduction occurring in the third stage. The following is a general life cycle though there is some variation in the various suborders. | Coccidia belong to the phylum Apicomplexa and are protozoan parasites of mammals, birds and reptiles. Coccidia have three major stages to their life cycle: Sporogony, Schizogony, Gametogony. The first two stages are asexual, with sexual reproduction occurring in the third stage. The following is a general life cycle though there is some variation in the various suborders. | ||
| − | ===Sporogony=== | + | ===Sporogony/Sporulation=== |
Thick shelled oocysts are passed unsporulated in the feaces of the host, these consist of a single nucleus in a large pool of protoplasm. Sporulation occurs when conditions in the environment are suitable; high humidity, good oxygenation, and temerpatures around 27C. The nucleus will divide a number of times depending on the species of coccidia and the number of sporocysts it will form. After division of the nucleus the protoplasm will form conical bodies around each nucleus budding off from the central core. The nucleus and conical body together will then form a sproblast. The sporoblast will creates a wall for itself by secreting materials, at the same time the protoplasm forms two sporoziotes within the sporocyst wall. This process can take between 2 and 4 hours under optimal conditions but may take considerably longer if conditions are not suitable. | Thick shelled oocysts are passed unsporulated in the feaces of the host, these consist of a single nucleus in a large pool of protoplasm. Sporulation occurs when conditions in the environment are suitable; high humidity, good oxygenation, and temerpatures around 27C. The nucleus will divide a number of times depending on the species of coccidia and the number of sporocysts it will form. After division of the nucleus the protoplasm will form conical bodies around each nucleus budding off from the central core. The nucleus and conical body together will then form a sproblast. The sporoblast will creates a wall for itself by secreting materials, at the same time the protoplasm forms two sporoziotes within the sporocyst wall. This process can take between 2 and 4 hours under optimal conditions but may take considerably longer if conditions are not suitable. | ||
| − | ===Schizogony=== | + | ===Merogony/Schizogony=== |
| − | + | Once the sporozoites have been formed the oocyst is an infective '''sporulated oocyst''' that is ingested by the host for the life cycle to continue. The remaining stages of the life cycle occur endogenously within the host. Once ingested the sporozoites are released from the oocyst and activated by trypsin or bile before invading intestinal epithelial cells. Once the sporozoites have invaded an epithelial cell they become rounded and are called trophozoites. This trophozoite will then divide into a number of elongated nucleated merozoites, collectively known as a meront. Once the meront has grown and matured sufficiently it ruptures along with the epithelial cell, freeing the merozoites to either infect another epithelial cell and repeat the progress or progress on to sexual reproduction. | |
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*Another generation of schizonts form which is the beginning of the sexual phase of reproduction called '''gametogony''' | *Another generation of schizonts form which is the beginning of the sexual phase of reproduction called '''gametogony''' | ||
Revision as of 13:10, 18 July 2010
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This article is still under construction. |
Coccidia belong to the phylum Apicomplexa and are protozoan parasites of mammals, birds and reptiles. Coccidia have three major stages to their life cycle: Sporogony, Schizogony, Gametogony. The first two stages are asexual, with sexual reproduction occurring in the third stage. The following is a general life cycle though there is some variation in the various suborders.
Sporogony/Sporulation
Thick shelled oocysts are passed unsporulated in the feaces of the host, these consist of a single nucleus in a large pool of protoplasm. Sporulation occurs when conditions in the environment are suitable; high humidity, good oxygenation, and temerpatures around 27C. The nucleus will divide a number of times depending on the species of coccidia and the number of sporocysts it will form. After division of the nucleus the protoplasm will form conical bodies around each nucleus budding off from the central core. The nucleus and conical body together will then form a sproblast. The sporoblast will creates a wall for itself by secreting materials, at the same time the protoplasm forms two sporoziotes within the sporocyst wall. This process can take between 2 and 4 hours under optimal conditions but may take considerably longer if conditions are not suitable.
Merogony/Schizogony
Once the sporozoites have been formed the oocyst is an infective sporulated oocyst that is ingested by the host for the life cycle to continue. The remaining stages of the life cycle occur endogenously within the host. Once ingested the sporozoites are released from the oocyst and activated by trypsin or bile before invading intestinal epithelial cells. Once the sporozoites have invaded an epithelial cell they become rounded and are called trophozoites. This trophozoite will then divide into a number of elongated nucleated merozoites, collectively known as a meront. Once the meront has grown and matured sufficiently it ruptures along with the epithelial cell, freeing the merozoites to either infect another epithelial cell and repeat the progress or progress on to sexual reproduction.
- 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