看国外 | 外国专家眼中的中国非瘟:一场人为灾难

看国外 2019-07-29 14:06:24

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Poor biosecurity practices, not disease virulence, are to blame for size of Chinese outbreak, scientists say.

科学家们表示,中国非瘟疫情的规模应归咎于糟糕的生物安全措施,而非疾病毒性。

Researchers long suspected that if African swine fever (ASF) reached China, the world would face an outbreak the likes of which it had never seen before.

长期以来,研究人员一直怀疑,如果非洲猪瘟(ASF)蔓延到中国,世界将面临前所未有的疫情。

Despite the headlines, ASF isn’t a particularly contagious disease. Yes, it’s capable of surviving outside a host much longer than most viruses — giving it an ability to remain virulent even after traveling long distances. But on the whole, it doesn’t spread nearly as quickly as other animal diseases such as avian influenza, and small outbreaks have occurred in Africa and across Europe throughout history. 

尽管经常上头条新闻,非洲猪瘟并不是一种特别具有传染性的疾病。是的,它在宿主外存活的时间比大多数病毒都要长,这使得它即使在长途旅行后也能保持毒性。但总的来说,它的传播速度远不及禽流感等其他动物疾病,历史上在非洲和整个欧洲也曾发生过小规模疫情。

Researchers suspect that human-caused risk factors such as high pig density and poor biosecurity practices ultimately laid the groundwork for today’s large-scale outbreak of ASF.

研究人员怀疑,人类引起的危险因素,如高猪群密度和糟糕的生物安全措施,最终为今天非洲猪瘟的大规模爆发奠定了基础。

“We had actually predicted in 2017 that China’s high pig density represented a high risk for a major ASF outbreak to occur,” said Dirk Pfeiffer who, alongside his colleagues, outlined the risk for an outbreak of ASF in China and Vietnam in the journal Veterinary Record. “It was just a matter of time.”

Dirk Pfeiffer和他的同事曾在《兽医记录》(Veterinary Record)杂志上概述了ASF在中国和越南爆发的风险,他提到“其实2017年我们就曾预测过,中国的高密度生猪养殖将是爆发非洲猪瘟的高风险因素”,“这只是时间问题” 。

Unlike influenza, ASF is not airborne and doesn’t spread particularly easily — infected pigs don’t become contagious for a week, sometimes longer, after they’ve begun to show symptoms. But ASF persists in the environment for months, and even a small amount of virus can result in illness. Consequently, the virus can be difficult to manage if the disease is not detected, and the infected pigs culled, soon after an outbreak is first detected.

不同于流感,非洲猪瘟不会通过空气传播,也不容易传播——受感染的猪在开始出现症状后一周内不会具有传染性,有时甚至更长时间。但是非瘟病毒能在环境中持续数月,即使是少量的病毒也能致病。因此,如果没有早发现,并在首次发现疫情不久就扑杀受感染的猪,那么这种病毒就很难控制。

In Africa, where the virus is endemic, outbreaks of ASF typically occur in small pockets that are relatively easy to contain, because that continent’s pig farms tend to be smaller and more widely dispersed. Across Europe, an emphasis on biosecurity measures to control ASF eventually stopped the disease, though it took decades to eradicate ASF entirely.

在非瘟病毒流行的非洲,非瘟暴发通常发生在相对容易控制的小区域,因为非洲大陆的养猪场往往规模较小,分布更广。在整个欧洲,对控制非瘟的生物安全措施的重视最终阻止了这种疾病,尽管彻底根除非瘟花了数十年的时间。

Perfect storm of risk factors

风险因素的风暴中心

But China is a perfect storm of risk factors, according to Pfeiffer, director of the Center for Applied One Health Research and Policy Advice at the City University of Hong Kong. The country contains nearly half of the globe’s swine population, producing the high densities that enable the virus to spread. But the majority of these pigs are raised on small farms of less than 100 pigs each, he said, where biosecurity may be less stringent.

Pfeiffer表示,中国是一个充满风险因素的风暴中心。这个国家拥有全球近一半的猪群,其密度之高使得病毒得以传播。但是,他说,这些猪中的大多数是在不足100头的小猪场里饲养的,这些猪场的生物安全可能不那么严格。

To complicate matters, China’s pork industry was on the cusp of industrialization, and farmers had begun shipping swine long distances to slaughterhouses thousands of miles away. All it took to kick off a major outbreak, Pfeiffer said, was the introduction of some contaminated pork product, feed or even equipment to enter China from Russia, where the genotype responsible for this current outbreak was already present.

更复杂的是,中国的猪肉工业正处于工业化的风口浪尖,养殖户把猪运到千里之外的屠宰场。Pfeiffer说,只要从俄罗斯引进一些受污染的猪肉产品、饲料,甚至是设备,就能引发一场大规模的疫情。俄罗斯已经出现了导致这次疫情爆发的基因型。

Given these circumstances, Pfeiffer believes it will take more than a vaccine to bring ASF under control.

考虑到这些情况,Pfeiffer认为控制非瘟需要的不仅仅是疫苗。

“We would not be able to achieve sufficiently high vaccination coverage to result in eradication of the ASF virus,” he said. “We will still need enhanced biosecurity measures and behaviors to be adopted by pig farmers, and it is unlikely that small farms in low- to middle-income countries will do that, for economic and socio-cultural reasons.”

他说:“我们无法实现足够高的疫苗覆盖率,以根除非瘟病毒。”“我们仍然需要加强养猪户的生物安全措施和行为,而由于经济和社会文化原因,中低收入国家的小型养猪场不太可能做到这一点。”

Eradicating the virus in China will require action not only from farmers, but from “millions of stakeholders involved in the pork value chain.” Chinese pig farms will likely become larger and begin to look much more like operations in the U.S. and Europe. But feed manufacturers, truckers and slaughterhouses will also have to reconsider their biosecurity protocol, he said.

要在中国根除这种病毒,不仅需要养殖户采取行动,还需要“涉及猪肉价值链的数百万利益攸关方”一起行动。他说:“中国养猪场很可能会变得更大,看起来更像美国和欧洲的猪场。但饲料制造商、卡车司机和屠宰场也将不得不重新考虑他们的生物安全协议。”

“The biosecurity issue is not just about farms,” Pfeiffer said. “It is also about slaughterhouses and pig transport vehicles, which need to be cleaned much better, and if food waste is used as pig feed, it needs to be properly heat treated. So, if you take that altogether, it is quite a tough task to make all those biosecurity changes in the pork food system.”

“生物安全问题不仅仅与农场有关,”Pfeiffer说。“这还涉及屠宰场和生猪运输车辆,它们需要更好地清洁。如果食品垃圾被用作生猪饲料,就需要进行适当的热处理。所以,如果把这些都考虑进去,要对猪肉食品系统进行所有这些生物安全方面的改革是一项相当艰巨的任务。”

文章来源:WATTAgNet

作者:EMMA PENROD

(文/爱猪网记者刘坤颖编译,爱猪网原创,转载请注明出处)


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