Summary Risk Profile on Cysticercus bovis in meat from domestic cattle
Bovine cysticercosis is a parasitic disease of cattle caused by the larval stage (Cysticercus bovis) of the human tapeworm Taenia saginata. The indirect life cycle of this taeniid involves only humans as the primary host and bovines as the intermediate host. Infection of humans with the adult tapeworm, known as taeniosis, occurs via the consumption of beef which has been insufficiently cooked or frozen to kill the cysticerci. Although multiple infections in humans can occur, most cases of taenio sis involve a single tapeworm, which can persist for years. The adult tapeworm develops to reproductive maturity as early as 10-12 weeks after infection. The adult tapeworm regularly sheds its most posterior and mature segments, called gravid proglottids, which are discharged from infected humans spontaneously or with defecation. Upon release, these proglottids contain thousands of infective eggs that can remain in the proglottid or be expelled into the surrounding fecal matrix or environment. E ggs can remain infective for several months under cool and moist environmental conditions, and can be disseminated by water and other fomites. Upon ingestion of contaminated feed or water by a bovine intermediate host, a hexacanth embryo, or oncosphere, hatches from the egg and penetrates the intestinal mucosa within a few hours to enter the cardiovascular or lymphatic system. Once it reaches a suitable muscle or other tissue site it develops into a cysticercus and becomes infective for a human host after about 10-12 weeks. In cattle, cysticerci are found predominantly in cardiac and skeletal musculature, and occasionally in other sites including liver, lungs, kidneys and lymph nodes. Cysticerci remain infective for several months to a year or more
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| Format: | Document biblioteca |
| Language: | English |
| Published: |
2013
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| Online Access: | https://openknowledge.fao.org/handle/20.500.14283/AU620E http://www.fao.org/3/a-au620e.pdf |
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