Difference between revisions of "Echinococcus granulosus"
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| − | ''Echinococcus granulosus'' is an important zoonosis as | + | ''Echinococcus granulosus'' is an important zoonosis as it's metacestode, the hydatid cyst, can develop in humans, as well as in many other animals. The hydatid cyst can grow to the size of a ping-pong ball in sheep, a tennis ball in horses, and a football in man. The metacestode of the related ''Echinococcus multilocularis'' (the alveolar cyst) is even more dangerous, but fortunately does not occur in the UK. |
==Hosts== | ==Hosts== | ||
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There may be several thousand adult tapeworms in an infected animal. The scolex is deeply buried in an intestinal crypt, so microscopic inspection of a mucosal scraping is necessary to detect infection. | There may be several thousand adult tapeworms in an infected animal. The scolex is deeply buried in an intestinal crypt, so microscopic inspection of a mucosal scraping is necessary to detect infection. | ||
| − | The terminal proglottid forms approximately half the total length. The proglottids are shed in the faeces. The oncosphere are capable of surviving in the environment, for up to two years. They are then ingested by the intermediate host e.g. the sheep, where they penetrate the gut lining. | + | The terminal '''proglottid''' forms approximately half the total length. The proglottids are shed in the faeces. The '''oncosphere''' are capable of surviving in the environment, for up to two years. They are then ingested by the intermediate host e.g. the sheep, where they penetrate the gut lining. |
The oncosphere then travels to the liver and the lungs, where the hydatid then begins growth. This is a slow process taking around 6-12 months, and the cysts are capable of growing up to 20cm in length. | The oncosphere then travels to the liver and the lungs, where the hydatid then begins growth. This is a slow process taking around 6-12 months, and the cysts are capable of growing up to 20cm in length. | ||
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[[Category:Taeniidae]] | [[Category:Taeniidae]] | ||
[[Category:To_Do_-_Max]] | [[Category:To_Do_-_Max]] | ||
| + | [[Category:To_Do_-_Review]] | ||
[[Category:Respiratory Parasitic Infections]][[Category:Cattle]] | [[Category:Respiratory Parasitic Infections]][[Category:Cattle]] | ||
[[Category:Sheep]] | [[Category:Sheep]] | ||
Revision as of 11:36, 26 July 2010
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This article is still under construction. |
| Also known as: | Dwarf dog tapeworm
|
Scientific Classification
| Kingdom | Animalia |
| Phylum | Platyhelminthes |
| Class | Cestoda |
| Order | Cyclophyllidea |
| Family | Taeniidae |
| Genus | Echinococcus |
| Species | E. granulosus |
Echinococcus granulosus is an important zoonosis as it's metacestode, the hydatid cyst, can develop in humans, as well as in many other animals. The hydatid cyst can grow to the size of a ping-pong ball in sheep, a tennis ball in horses, and a football in man. The metacestode of the related Echinococcus multilocularis (the alveolar cyst) is even more dangerous, but fortunately does not occur in the UK.
Hosts
Intermediate hosts: Ruminants and man.
Definitive hosts: Dogs and wild canids.
Identification
The adults are 6 mm in length. They have a scolex and three or four individual segments. The brood capsules float in the vesicular fluid, forming 'hydatid sand.'
Life-Cycle
There may be several thousand adult tapeworms in an infected animal. The scolex is deeply buried in an intestinal crypt, so microscopic inspection of a mucosal scraping is necessary to detect infection.
The terminal proglottid forms approximately half the total length. The proglottids are shed in the faeces. The oncosphere are capable of surviving in the environment, for up to two years. They are then ingested by the intermediate host e.g. the sheep, where they penetrate the gut lining.
The oncosphere then travels to the liver and the lungs, where the hydatid then begins growth. This is a slow process taking around 6-12 months, and the cysts are capable of growing up to 20cm in length.
The definitive host e.g. the dog, then ingests the offal of the intermediate host, and the life cycle continues.
The prepatent period of E. granulosus is 6-7weeks. No more than one gravid segment is passed by each tapeworm each week. This species therefore has a low biotic potential.