On present understanding, H5 and H7 viruses are introduced to poultry flocks in their low pathogenic form.
据目前所知，H5和H7型病毒以低致病形式传给禽类。
It spreads very rapidly through poultry flocks, causes disease affecting multiple internal organs, and has a mortality that can approach 100%, often within 48 hours.
它在禽类中传播非常迅速，感染多个内脏器官，通常在48小时内，死亡率可达到100%。
On a more sobering note, the report notes that avian flu is now endemic in the poultry flocks of many countries in the region and indeed has spread to Europe and central Asia.
报告以一种使人清醒的口气指出，禽流感目前在东亚很多国家的禽类中流行，并确实已传播到欧洲和中亚。
Culling of infected or potentially exposed poultry flocks is a standard control measure that has proved effective in halting past epidemics of avian influenza in several countries.
剔除感染的或有暴露可能的禽类是公认的一项有效的控制措施，通过它成功地阻断了以前几个国家发生的禽流感流行。
Considerable circumstantial evidence suggests that migratory birds can introduce low pathogenic H5 and H7 viruses to poultry flocks, which then mutate to the highly pathogenic form.
相当多的旁证表明侯鸟能够传播低致病性禽流感的H5和H7亚型病毒给家禽，然后，变异成高致病性类型。
Poultry flocks are worst affected, transmitting the virus easily in crowded conditions; however, the infection of wild birds is also an increasing concern.
家禽最容易感染该病，因为拥挤的环境使传播该病毒变得容易。但野鸟感染病例变得越来越多。
Poultry flocks are worst affected, transmitting the virus easily in crowded conditions; however, the infection of wild birds is also an increasing concern.
家禽最容易感染该病，因为拥挤的环境使传播该病毒变得容易。但野鸟感染病例变得越来越多。
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