Caryospora bubonis
| Caryospora bubonis | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Caryospora bubonis | ||||||||||||
| ( Cawthorn & Stockdale , 1980) |
Caryospora bubonis is a unicellular organism from the group of coccidia (Coccidia) with a parasitic way of life, which leads to coccidiosis in the affected hosts. The great horned owl ( Bubo virginianus ),native to North America,has been identified as the only final host to date, but the experimental infection was successful in both the whooping crane ( Grus americana ) and the sandhill crane ( Grus canadensis ). Other vertebrates from the bird's food spectrum, primarily mice, probably serveas intermediate hosts .
distribution
Nothing is known about the specific distribution of the pathogen; its distribution area is probably identical to that of the host animals and is therefore limited to parts of North America.
features
As with all coccidia, Caryospora bubonis differs in both shape and size depending on the stage. The cells of the free and infectious form in liquids or fresh preparations are arched and reach sizes of two to five micrometers. The oocysts , on the other hand, are round and contain the mature sporozoites .
Development cycle
The life cycle of Caryospora bubonis can take place either directly from final host to final host or indirectly, whereby an intermediate host is required in the indirect form. The cycle itself is no different from other known coccidia.
Oocysts develop in the ultimate host and are excreted with the faeces and ingested by the intermediate host. They contain a sporocyst with four sporozoites and can remain infectious for long periods of time. In the intermediate host (vertebrates and birds) the sporocysts hatch and actively penetrate into nucleated cells, where they form tachyzoites through asexual division and float into the blood. Tissue cysts form in the tissues and persist mainly in the muscles , but also in the brain or the retina of the eye . In this form, they are then in turn taken up by the ultimate host, who eats the intermediate host.
The bradyzoites are released in the intestine and penetrate the epithelial cells . There is a schizogony (asexual reproduction) take and / or there are macrogamont and microgamonts formed. The macrogamonts form macrogametes, while a microgamont forms microgametes. The macrogamete is fertilized by a microgamete and a zygote (diploid) develops, which then matures into an unsporulated oocyst. This is then excreted with the feces and, under the influence of oxygen, matures into infectious sporulated oocysts.
literature
- PHG Stockdale, RJ Cawthorn: The Coccidian Caryospora bubonis in the Great Horned Owl ( Bubo virginianus ) . Journal of Protozoology 28 (2), 1980; Pages 255-257