H5N1 Kills 50 Million Birds, Spreads to Mammals

Since 2022, the virus has infected more than 100 million birds worldwide, killed more than 50 million, and killed millions of poultry.

This year saw the worst outbreak of highly pathogenic avian influenza H5N1 worldwide, killing millions of birds. The virus, known to cause severe illness and death in birds, has also been detected in mammals and humans.

This has put health officials on high alert about the impact of the outbreak on public health.

high bird mortality

There are many different subtypes of avian influenza, but H5N1 is a highly pathogenic subtype that kills birds. Since 2022, the virus has infected more than 100 million of her birds worldwide, killed more than 50 million, and killed millions of poultry. Unlike previous outbreaks of highly pathogenic subtypes of avian influenza, H5N1 has had a major impact on wild bird species, including many endangered wild bird species.

It is difficult to ascertain how many wild birds have been affected by the virus, but the largest impact on domestic poultry seen so far is in addition to eagles, pelicans, geese, waterfowl, gulls, falcons and sandpipers.・A significant impact was seen on plovers. , at least in the United States

The impact of H5N1 on wild bird populations depends on several factors, including the level of exposure, geographical location, and migration patterns of affected species.

High mortality rates in wild birds due to viruses can have significant ecosystem impacts, such as vulnerability to predators and changes in species composition in affected ecosystems, and impact not only birds but also biodiversity. may give.

It raises concerns about the spread of the virus among endangered bird populations.

In recent weeks, at least 20 California condors, which have been endangered since the 1980s, were reportedly infected with H5N1 bird flu. With an estimated 300 condors left in the wild, this represents about 7% of the species. H5N1 has also killed scores of bald eagles and Caspian terns in the United States since January 2022, and thousands of cranes in Israel. Last year, H5N1 hit a colony of endangered African herring penguins in South Africa, killing at least 30 penguins. The uncontrolled spread of the virus could therefore devastate already vulnerable populations of endangered birds around the world, leading to mass extinctions of some species.

spread to animals

The highly contagious H5N1 virus can occasionally spill over from birds to animals through direct or indirect contact with infected birds and their droppings.

Worryingly, there have been several reports of the spread of H5N1 to mammals during the current outbreak from various countries, and apart from domestic animals such as dogs and cats, sea lions, mink, foxes, wild bears, It infects species such as skunks.

In 2023 alone, H5N1 killed more than 3,000 sea lions in Peru. In a recent yet-to-be-peer-reviewed study, scientists found that the virus can spread efficiently among ferrets in the laboratory. , reported in heavily bred mink on farms in Spain.

Transmission of H5N1 from birds to mammals is rare, but when it does occur, it could be a cause for concern because the virus could accumulate mutations and potentially acquire the ability to start outbreaks in humans. There is a nature. H5N1 has a high mortality rate of over 60% in humans and is transmitted to humans primarily through close contact with infected birds and animals, handling of infected poultry or exposure to contaminated environments.

In recent months, sporadic cases of H5N1 infection in humans have also been reported in Ecuador, Cambodia and most recently Chile. Given the ongoing threat of influenza pandemics, monitoring spread in mammalian populations is important in areas of close human-animal contact. However, the World Health Organization (WHO) has assessed her risk of H5N1 to humans as low because the virus is not yet efficiently transmitted between humans.

However, large and unabated outbreaks in avian species and less rare spread to mammals could potentially provide an opportunity for the virus to adapt to mammalian infection.

Strengthen countermeasures

The current H5N1 outbreak continues unabated with devastating impacts on bird populations worldwide, with significant ecological and economic impacts, making it more difficult for birds and humans to survive. There has never been a better time to start preparatory efforts towards building better and more efficient vaccines and genomics surveillance to map the current situation. Evolving virus. Enhanced biosecurity measures are also needed to protect both animals and public health.

( Bani Jolly and Vinod Scaria are researchers at the CSIR Institute of Genomics and Integrative Biology (CSIR-IGIB).Opinions expressed are personal)