Why Unprecedented Bird Flu Outbreaks Are Concerning Scientists

Why Unprecedented Bird Flu Outbreaks Are Concerning Scientists thumbnail

A highly contagious and deadly strain of the avian influenza virus has infected millions of birds across North America, Asia, Africa, Europe and Asia. Scientists are especially concerned about the spread of the virus in wild birds. These outbreaks pose a serious risk to vulnerable species and are difficult to contain. They also increase the chance that the virus will spread to humans.

Since October, the H5N1 strain has caused nearly 3,000 outbreaks in poultry in dozens of countries. More than 77 million birds have been culled to curb the spread of the virus, which almost always causes severe disease or death in chickens. Another 400,000 non-poultry birds, such as wild birds, have also died in 2,600 outbreaks — twice the number reported during the last major wave, in 2016-17.

Researchers believe that the virus is spreading faster in wild birds than ever before, making it difficult to contain outbreaks. The virus is spread by wild birds, whose migration patterns determine where and when it will spread. Large outbreaks will likely continue in Asia and Europe, with infections spreading to other continents like South America and Australia.

Although people can get the virus, it is rare. Since October, there have been only two cases reported. One each in the United Kingdom (UK) and the United States (US). Scientists are concerned that the virus is more likely to spread into humans due to its high levels in bird populations. The Avian influenza viruses are slow to change over time. However, the right mutation could make them more transmissible to humans and other species, according Ian Barr, deputy director at the WHO-collaborating influenza centre at Doherty Institute, Melbourne, Australia. He says that these viruses are “like ticking time bombs.” He says that occasional infections are not a problem, but the gradual gaining function of these viruses is what is really of concern.

Virus origin

The highly pathogenic H5N1 strain emerged in commercial geese in Asia in around 1996, and spread in poultry throughout Europe and Africa in the early 2000s. By 2005, the strain was causing mass deaths in wild birds, first in East Asia and then in Europe. Andy Ramey, a researcher wildlife geneticist at US Geological Survey Alaska Science Center, Anchorage, said that the strain has infected wild birds in many countries. Ramey claims that H5N1 has become more adaptable to wild birds through repeated spillovers. He says it’s “now an emerging wildlife disease”.

In 2014,, a new H5 lineage called 2.3.4.4 emerged and began infecting wild birds. This opened up the possibility for the virus’s spread to North America. Since then, the lineage has dominated all outbreaks in the world, even the current ones.

Some wild bird species are more affected than others. For instance, some infected mallard ducks (Anas platyrhynchos) show no signs of disease, whereas the virus killed roughly 10% of the breeding population of barnacle geese (Branta leucopsis) in the Norwegian archipelago of Svalbard late last year and hundreds of Dalmatian pelicans (Pelecanus crispus) in Greece earlier this year. Wildlife researchers are trying understand how the virus affects different species. They are particularly concerned about the virus’s impact on vulnerable bird species with smaller populations or restricted geographic ranges, and species that are particularly susceptible to infection, such as whooping cranes (Grus americana) and emperor geese (Anser canagicus), Ramey says.

Ramey says that only a small percentage of wild bird cases are reported and diagnosed. He believes that more monitoring could reveal the true extent of wild bird mortality.

Controlling spread

Better monitoring of infected wild bird could alert poultry facilities to the possibility of future outbreaks. However, large populations of poultry or migratory birds are at high risk for further outbreaks, according to Keith Hamilton, head, department for preparedness, resilience and health at the World Organisation for Animal Health.

Tracking disease in wild birds can be resource-intensive and difficult due to the sheer number of them, Hamilton states. Hamilton suggests focusing surveillance on areas that are more likely to be infected, such as breeding grounds or flyways.

A vaccine for poultry could help reduce the spread of the disease and decrease the number of birds in production plants, according to Michelle Wille, an Australian wild-bird virologist at The University of Sydney. The poultry industry can improve biosecurity by limiting entry to facilities, protecting their water supplies and decreasing contact between wild birds and poultry.

Although poultry populations can be controlled to prevent the spread of highly pathogenic Avian Influenza, researchers stress that wild birds should be left alone to reduce the risk of further outbreaks. Lina Awada, a veterinarian epidemiologist at World Organisation for Animal Health, said that killing wild birds to prevent more infections would not work due to their large size and wide ranges. She says it could make matters worse as wild-bird behaviours and movements would be disrupted, which could lead to further spread of the virus.

” In the same way that we shouldn’t shoot bats due to coronavirus, Wille states that it is best to not try to kill wild birds.

Researchers believe that a holistic approach is necessary to understand how avian flu spreads through wild birds, poultry, and humans. Collaboration between animal-health groups and public-health researchers is crucial for preventing spillover events to people. Wille states, “If we control it in poultry, then we control it in humans, and it is likely that we control the wild birds, too.”

This article is reproduced with permission an

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