The worst bird flu outbreak in US history is 'wiping out everything in numbers we've never seen before.' Here's what you need to know.

• A new strain of bird flu, also known as avian influenza, is spreading across the US.
• The H5N1 strain is causing a variety of new problems and has killed more than 58 million birds.
• One scientist said the variant is "wiping out everything in numbers we've never seen before." 

The US is currently experiencing its worst-ever outbreak of bird flu, also known as avian influenza, and a new strain could become endemic in the US, a new study has found.

The outbreak is "wiping out everything in numbers we've never seen before," Professor Jennifer Mullinax from the University of Maryland told Sky News. The new H5N1 strain has already killed over 58 million chickens, turkeys, and other birds, per Reuters.

The US is no stranger to the impact of the disease, with the H5N8 strain leading to the culling of 50 million birds in 2015. But the new, more contagious strain is particularly affecting wild birds, Sky reported.

Johanna Harvey, a postdoctoral researcher and lead author of the study published in Conservation Biology at the University of Maryland, said, "Unlike H5N8, this disease is heavily impacting wild birds." 

"It's difficult to estimate how many birds are truly affected across wild populations, but we're seeing dramatic disease impacts in raptors, sea birds, and colonial nesting birds. And we now have the highest amount of poultry loss to avian influenza, so this is a worst-case scenario," she added.

The researchers believe that bird flu will probably become endemic, where a disease is constantly present within an area or community in the US, which could affect food security and the economy.

Last week the US Government started testing four new bird flu vaccines to try and protect the poultry from this mass outbreak, per Reuters.

Are humans in danger? 

The disease can and does affect humans, but it's rare. 

The first case of H5N1 infection in a human in the US was reported in April 2022. A man was also diagnosed with the virus in Chile, according to the World Health Organization.

Most cases of human infection have been found in Southeast Asia, per data from the Centers for Disease Control and Prevention. There were only three cases of human infection in 2023, two in Cambodia and one in China. One of the people infected in Cambodia, an 11-year-old girl, died from the illness. 

Speaking about this death to AP, Professor James Wood, head of the department of veterinary medicine at Cambridge University, said there is no reason to be unduly concerned about human infection with avian influenza.

"Tragic though this case in Cambodia is, we expect there to be some cases of clinical disease with such a widespread infection. Clearly, the virus needs careful monitoring and surveillance to check that it has not mutated or recombined, but the limited numbers of cases of human disease have not increased markedly, and this one case in itself does not signal the global situation has suddenly changed," he said.

Markets are in trouble

Farmers and the markets are being hit hard by the ravages of avian flu.

In January, Insider's George Glover explained into the egg crisis facing Americans as prices surged almost 60% in 2022 due to the influenza outbreak.

The average cost of a dozen eggs rose 59% last year, according to the Bureau of Labor Statistics, with prices more than doubling in West Virginia and six states in the upper Midwest.

The jump was caused by the unprecedented spread of disease and 2022's high inflation rates raising farmers' costs — and it doesn't look like it will change soon.