Bird Flu Spread Increasing, Killing South American Wildlife

Bird Flu Spread Increasing, Killing¹ South American Wildlife

　　The deadly H5N1 bird flu virus is spreading more aggressively than ever before since its arrival in South America in 2022. It is killing wild birds and marine² mammals on the continent.

　　Reuters recently spoke³ to eight experts in bird flu science. All said the current spread raises the risk of the virus becoming a bigger threat to humans.

　　The more immediate⁴ concern is that the disease, which once affected⁵ mostly birdlife, appears to be spreading between mammals.

　　The disease has already killed several dolphins in Chile and Peru. It has also killed about 50,000 seals and sea lions along the coasts and at least half a million birds across South America.

　　Scientists have not yet tested infections in living animals to confirm mammal-to-mammal passage of the virus. But they believe it is very likely.

　　"It's almost certainly happened," said Richard Webby. He is a virologist at St. Jude's Children's Research Hospital in Memphis, Tennessee. "It's pretty hard to explain some of these large infections and die off without having mammal-to-mammal spread."

　　The same version of the virus has appeared in many bird species. Among them are migrating species, scientists told Reuters.

　　As climate change continues, animals are forced to move into new territories, often mixing with animals -- and viruses -- that are new to them.

　　"It's a matter of time before you will detect the first South American strain in North America," said Alonzo Alfaro-Nunez, a viral ecologist at the University of Copenhagen in Denmark.

　　Human risk

　　The growing concern led the intergovernmental Pan American Health Organization (PAHO) to gather health experts and officials for a meeting this week in Rio de Janeiro, Brazil.

　　The group plans to launch the world's first regional program to supervise bird flu spread. The program will run observation and response efforts, a PAHO official told Reuters.

　　Since the virus was first detected in Colombia in October 2022, there have been two known cases in humans on the continent. One was in Ecuador. The other was in Chile. Birds passed the virus in each case.

　　The patients survived. But often, H5N1 kills. About 60 percent of human cases of the virus end in death.

　　The World Health Organization is unlikely to raise the H5N1 risk level for humans from the current "low" right now. The experts would require evidence of human-to-human transmission or signs of viral changes that would target humans, experts said.

　　Several drugmakers have said they are developing bird flu vaccines⁶ for humans.

　　"We're seeing (the virus) do... little evolutionary⁷ steps that are on the long-term moving towards a potential human infection," said Ralph Vanstreels. He is a researcher at the University of California, Davis. He is studying South American variants⁸ of H5N1.

　　Regional response

　　With health officials and experts meeting in Rio this week, Latin American countries will be pressured to increase disease surveillance in the wild.

　　The region's data is lacking and limited resources have left scientists struggling to understand how the disease is spreading in the wild. Scientists expect the number of cases is probably much higher than reported. Some cases are not getting laboratory testing.

　　Bolivia, for example, did not register a case in the wild last year. But the disease has been reported in surrounding countries, said Manuel Jose Sanchez Vazquez, a disease expert for PAHO's animal health center.

　　Overseeing the disease response can also be complex, Sanchez noted⁹. Public health officials deal with threats to humans. Agricultural experts and veterinarians deal with health threats to farm animals, including birds, cows and pigs. But for wild animal health, care and supervision¹⁰ is provided mostly by environmental officials.

　　The new regional commission is expected to be announced on Thursday. The group would aim to set methods for observing, treating and reporting cases among government agencies. It could also help in sharing laboratory resources.

　　"We are worried and we are vigilant¹¹," Sanchez said. "The more adaptation of the virus to mammals, the more likely it is that transmission to humans could happen."

　　Words in This Story

　　detect — v. to discover or determine the existence, presence, or fact of

　　region — n. an administrative¹² area, division, or district

　　response — n. an act or instance of replying; answer

　　evolution — n. a process of change in a certain direction

　　potential — adj. existing in possibility : capable of development into actuality

　　vigilant — adj. alert to signs of danger

　　adaptation — n. modification¹³ of an organism or its parts that makes it more fit for existence under the conditions of its environment

　　veterinarian — n. a medical doctor of animals

1 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

2 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

3 spoke   

n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说

参考例句：

• They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
• The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。

4 immediate   

adj.立即的；直接的，最接近的；紧靠的

参考例句：

• His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
• We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。

5 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

6 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。

7 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

8 variants   

n.变体( variant的名词复数 )；变种；变型；（词等的）变体

参考例句：

• Those variants will be preserved in the'struggle for existence". 这些变异将在“生存竞争”中被保留下来。 来自辞典例句
• Like organisms, viruses have variants, generally called strains. 与其他生物一样，病毒也有变种，一般称之为株系。 来自辞典例句

9 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

10 supervision   

n.监督，管理

参考例句：

• The work was done under my supervision.这项工作是在我的监督之下完成的。
• The old man's will was executed under the personal supervision of the lawyer.老人的遗嘱是在律师的亲自监督下执行的。

11 vigilant   

adj.警觉的，警戒的，警惕的

参考例句：

• He has to learn how to remain vigilant through these long nights.他得学会如何在这漫长的黑夜里保持警觉。
• The dog kept a vigilant guard over the house.这只狗警醒地守护着这所房屋。

12 administrative   

adj.行政的，管理的

参考例句：

• The administrative burden must be lifted from local government.必须解除地方政府的行政负担。
• He regarded all these administrative details as beneath his notice.他认为行政管理上的这些琐事都不值一顾。

13 modification   

n.修改，改进，缓和，减轻

参考例句：

• The law,in its present form,is unjust;it needs modification.现行的法律是不公正的，它需要修改。
• The design requires considerable modification.这个设计需要作大的修改。