An infectious and deadly strain of bird flu virus has infected tens of millions of domestic birds throughout Europe, Asia, Africa, and North America. But scientists are deeply concerned about the unprecedented spread of wild birds – the outbreak poses a serious threat to endangered species, which are difficult to contain and increase the likelihood that the virus will spread to humans.
Since October, the H5N1 virus has caused an outbreak of nearly 3,000 chickens in many countries. More than 77 million chickens have been killed to prevent the spread of the virus, which causes serious diseases or deaths in chickens. Some 400,000 non-poultry birds, such as wild birds, have also died in the 2,600 outbreak – more than double the number reported during the last major wave of 2016-17.
Scientists are concerned that high levels of the virus in around the bird population
Researchers say that the virus seems to spread more easily to wild birds than ever before, making it increasingly difficult to prevent the spread of the disease. Wild birds help to transport the virus around the world, with their migration determining when and where it will spread next. The Asian and European regions will likely continue to experience major outbreaks, and the disease could spread to as far away from the affected continents as South America and Australia.
Although people can get the virus, infections are rare. Only two cases have been reported since October, one in the United Kingdom and the United States. But scientists are concerned that high levels of the virus around the bird population mean that they are more likely to become infected in humans. Bird flu viruses change little over time, but mutations can make them more susceptible to infection in humans and other species, ”said Ian Barr, deputy director of the World Health Organization (WHO) at Doherty Institute in Melbourne, Australia. He says: “These germs are like time bombs. “Occasional infections are not a problem – it is a gradual detection of the effectiveness of these germs,” he said.
The origin of the virus
The most dangerous form of H5N1 appeared in commercial guinea fowl in Asia around 1996, and it spread to poultry throughout Europe and Africa in the early 2000’s. In 2005, the species caused a number of deaths in wild birds, first in East Asia and then in Europe. Since then, the species has repeatedly attacked wild birds in many parts of the world, says Andy Ramey, a wildlife geneticist at the US Geological Survey Alaska Science Center in Anchorage. With repeated flow, Ramey says, H5N1 seems to be accustomed to wild birds. “Now it is an outbreak of wildlife,” he said.In 2014, a new H5 virus that was more dangerous – called 2.3.4.4 – emerged and began infecting wild birds without killing them regularly. This created the possibility of the virus spreading to North America for the first time. Descendants have always been the best in the world, including modern ones.
Why the virus affects species
The virus affects more species of wild birds than others. For example, some infected Mallard ducks do not show any signs of the disease, and the virus killed about 10% of the geese on the Norwegian island of Svalbard late last year and hundreds of Dalmation pelicans in Greece earlier this year. Wildlife researchers are trying to understand why the virus affects species so differently. They are particularly concerned about the impact of the virus on endangered or limited bird species, as well as species at risk of infection, such as whooping cranes and emperor geese, says Ramey.
Ramey adds that only a small percentage of incidents in wild birds are detected and reported. More vigilance may reveal the true death toll on wild birds, he says.Better monitoring of infected wild birds can also help to warn poultry communities about the risk of future outbreaks – although regions with large poultry or migratory birds are at high risk of outbreaks no matter how good their surveillance is, said Keith Hamilton, head of department. department of preparedness and resilience in the World Animal Health Organization.Tracking diseases in wild birds uses resources and is challenging due to their large population, Hamilton said. He suggests targeting surveillance of areas where they may be exposed to the virus, such as popular airlines or breeding grounds.
An effective poultry vaccine could help stop the spread, as well as a reduction in the number of birds in production facilities, says Michelle Wille, a veterinarian at the University of Sydney in Australia. The poultry industry can also continue to improve animal protection by restricting access to facilities, protecting their water resources and reducing contact between poultry and wild birds.
Killing wild birds to prevent other diseases
Although chickens can be killed to prevent the spread of bird flu, researchers emphasize that wild birds should not be harmed in order to reduce the spread of disease. Killing wild birds to prevent other diseases will not work because of their size and population, says Lina Awada, a veterinarian at the World Animal Health Organization. It could make the situation worse, as it would disrupt wildlife movement and behavior, helping the virus to spread more widely, he said.
“In the same way we should not be shooting bats because of the coronavirus, the solution to this is not to try to kill wild birds,” said Wille.The researchers say that what is needed is an integrated approach to how bird flu spreads to wild birds, chickens, and humans. Collaboration between public health researchers and animal health groups is essential to documenting human events. “If we control this in poultry, we control this in humans, and we may be controlling this in wild birds,” Wille said.
Source Journal Reference:Brittney J. Miller,Why unprecedented bird flu outbreaks sweeping the world are concerning scientists, Nature news Feature (2022), doi: https://doi.org/10.1038/d41586-022-01338-2
