[ti:Bird Flu Spread Increasing, Killing South American Wildlife]
[al:As It Is]
[ar:VOA]
[dt:2024-03-18]
[by:www.voase.cn]
[00:00.00]The deadly H5N1 bird flu virus is spreading more aggressively than ever before since its arrival in South America in 2022. 
[00:14.66]It is killing wild birds and marine mammals on the continent.
[00:20.64]Reuters recently spoke to eight experts in bird flu science.
[00:27.26]All said the current spread raises the risk of the virus becoming a bigger threat to humans.
[00:36.39]The more immediate concern is that the disease, which once affected mostly birdlife, appears to be spreading between mammals.
[00:49.39]The disease has already killed several dolphins in Chile and Peru.
[00:56.10]It has also killed about 50,000 seals and sea lions along the coasts and at least half a million birds across South America.
[01:09.77]Scientists have not yet tested infections in living animals to confirm mammal-to-mammal passage of the virus. 
[01:21.15]But they believe it is very likely.
[01:25.01]"It's almost certainly happened," said Richard Webby. 
[01:29.68]He is a virologist at St. Jude's Children's Research Hospital in Memphis, Tennessee.
[01:37.85]"It's pretty hard to explain some of these large infections and die off without having mammal-to-mammal spread."
[01:48.32]The same version of the virus has appeared in many bird species. 
[01:54.36]Among them are migrating species, scientists told Reuters.
[01:59.93]As climate change continues, animals are forced to move into new territories, often mixing with animals -- and viruses -- that are new to them.
[02:13.59]"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.
[02:31.04]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.
[02:47.34]The group plans to launch the world's first regional program to supervise bird flu spread.
[02:55.59]The program will run observation and response efforts, a PAHO official told Reuters.
[03:05.12]Since the virus was first detected in Colombia in October 2022, there have been two known cases in humans on the continent.
[03:18.34]One was in Ecuador. The other was in Chile. Birds passed the virus in each case.
[03:26.61]The patients survived. But often, H5N1 kills. About 60 percent of human cases of the virus end in death.
[03:39.82]The World Health Organization is unlikely to raise the H5N1 risk level for humans from the current "low" right now. 
[03:52.72]The experts would require evidence of human-to-human transmission or signs of viral changes that would target humans, experts said.
[04:06.27]Several drugmakers have said they are developing bird flu vaccines for humans.
[04:13.98]"We're seeing (the virus) do... little evolutionary steps that are on the long-term moving towards a potential human infection," said Ralph Vanstreels.
[04:27.04]He is a researcher at the University of California, Davis. He is studying South American variants of H5N1.
[04:39.77]With health officials and experts meeting in Rio this week, Latin American countries will be pressured to increase disease surveillance in the wild.
[04:53.20]The region's data is lacking and limited resources have left scientists struggling to understand how the disease is spreading in the wild.
[05:05.67]Scientists expect the number of cases is probably much higher than reported. Some cases are not getting laboratory testing.
[05:17.91]Bolivia, for example, did not register a case in the wild last year.
[05:24.55]But the disease has been reported in surrounding countries, said Manuel Jose Sanchez Vazquez, a disease expert for PAHO's animal health center.
[05:38.80]Overseeing the disease response can also be complex, Sanchez noted. Public health officials deal with threats to humans.
[05:50.69]Agricultural experts and veterinarians deal with health threats to farm animals, including birds, cows and pigs.
[06:01.56]But for wild animal health, care and supervision is provided mostly by environmental officials.
[06:12.21]The new regional commission is expected to be announced on Thursday. 
[06:17.14]The group would aim to set methods for observing, treating and reporting cases among government agencies.
[06:27.29]It could also help in sharing laboratory resources.
[06:33.57]"We are worried and we are vigilant," Sanchez said.
[06:38.42]"The more adaptation of the virus to mammals, the more likely it is that transmission to humans could happen."
[06:48.73]I'm Caty Weaver.