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The persistence of bird flu -

Bird flu remains a growing issue, especially in the United States, persisting longer than expected and raising concerns about its potential impact on human health. The more the virus circulates, the greater the chance it will evolve into a form more dangerous to humans.

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The H5N1 strain -

The primary bird flu strain in the US, H5N1, mainly affects birds but has spread to mammals, including house cats and cattle. It has caused millions of bird deaths, which has recently led to shortages of eggs and poultry.

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Origins -

Avian influenza has been documented since at least the late 1800s. The first recognized outbreak was in 1878 in Italy, where it was described as “fowl plague.” Initially, little was known about the virus, and its impact was largely limited to poultry.

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Uncovered in Scotland -

The highly pathogenic H5N1 strain, now infamous for its role in bird flu outbreaks, was first detected in birds in Scotland in 1959. But it wasn’t until the late 1990s that it became widely recognized as a significant global threat.

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Deadly nature -

Between 2003 and 2010, over 500 human cases of H5N1 were reported, with a mortality rate exceeding 50%. Unlike seasonal flu, H5N1 caused severe respiratory failure that often led to death, making it one of the deadliest influenza viruses to infect humans.

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The first case in American cattle -

In 2024, H5N1 was detected in American dairy cattle for the first time. This marked a worrying shift, as cows were not previously known to be significant hosts for bird flu. The virus’ presence in milk raised new food safety questions.

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New variants -

Besides H5N1, another bird flu virus, H5N9, has been detected in California, and a new H5N1 variant has recently been spreading more rapidly among cattle. There has even been a potential case of a cat infecting its owner, which raises further fears of an evolving strain more capable of human transmission.

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The looming pandemic threat -

Experts fear that continued human infections could lead to a virus capable of human-to-human transmission. If such a strain emerges, a new pandemic could follow. It is critical to track the virus and prevent its spread as much as possible.

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Severity -

Historically, over half of human H5N1 infections were fatal, but recent cases in the US have been significantly milder. Experts believe that this may be a sign that the virus is weaker.

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Possible reasons -

Scientists also speculate that the virus may have become less virulent. Others suggest that human immunity from seasonal flu may offer some protection, or the way people are getting infected (mainly from cattle) might make the disease less severe than when it is transmitted from birds.

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Different species -

A cattle-infecting H5N1 variant seems milder for humans, while another variant called D1.1 that affects wild birds and poultry is more dangerous. This explains why some infections, like those in house cats, appear particularly severe compared to cattle-related cases.

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Cows -

The more dangerous D1.1 strain has been detected in cattle, while dairy workers have also tested positive for this strain. Experts have highlighted that the virus’ risk to humans is not negligible.

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The risk of infection from food -

Nonetheless, no confirmed human infections in the United States have been linked to contaminated food. Meat and dairy products undergo rigorous testing, and proper cooking and pasteurization effectively kill the virus, which ensures that commercially sold products remain safe for consumption.

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Pasteurization -

Pasteurization successfully neutralizes H5N1 in milk and eggs. Despite the discovery of trace amounts of the virus in milk, testing confirms that pasteurized dairy poses no known risk to human health.

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Raw milk -

Unpasteurized milk, on the other hand, poses a real risk. Some suspected cases have linked bird flu to raw milk consumption, although this has not been definitively proven. Experts strongly advise against drinking raw milk due to the potential for high viral loads.

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Unpasteurized pet food -

Pets are also at risk from raw food products. Many cases have surfaced in which house cats have died after consuming raw, contaminated pet food. Some unpasteurized pet dairy products in the US have already been recalled for contamination concerns.

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Food industry -

Bird flu in the US has led to the culling of millions of animals, disrupting the poultry, egg, and dairy industries. With over 900 cattle herds affected and countless birds killed, shortages are widespread, and food prices continue to climb.

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Long recovery periods -

Once a farm is infected, it must undergo extensive cleaning and pass a biosecurity inspection before operations can resume. This process takes months, which delays the replenishment of livestock and further strains the food supply chain.

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Biosecurity measures -

Strict biosecurity measures on farms and in food processing plants include sanitizing equipment and limiting outside contamination. Preventing the virus from spreading between farms is key to controlling its impact on agriculture.

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Infected chickens -

Even when chickens survive the virus, they stop laying eggs. This, combined with mass culling efforts, has contributed to egg shortages and soaring prices.

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Dairy cows also suffer -

Cattle infections mean infected dairy cows temporarily stop producing milk. Even after recovering, some cows may not regain full milk production. This creates additional disruptions in the dairy industry and leads to milk shortages.

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Buying pasteurized products -

Experts urge people to purchase only pasteurized animal products to reduce infection risks. Those who choose to consume raw milk should at least boil it first, as heating can help neutralize the virus and make it safer for consumption.

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Avoiding sick animals -

Pets and humans alike should steer clear of sick or dead birds, as well as infected or weakened cats. Since the virus spreads through secretions, minimizing contact with affected wildlife or domestic animals lowers transmission risk.

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Protective gear -

Workers exposed to infected animals should wear face shields, masks, gloves, and coveralls. This precaution limits their risk of contracting the virus, especially for those in high-exposure environments like poultry farms, dairies, and veterinary clinics.

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Seasonal flu vaccines -

Although not directly protective against H5N1, flu vaccines could help reduce the severity of bird flu infections. Keeping flu rates down also lowers the risk of coinfection (where a person is infected with both bird flu and seasonal flu at the same time), which could lead to dangerous new viral mutations.

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Increasing flu testing -

To prevent unnoticed human-to-human transmission, the Centers for Disease Control and Prevention (CDC) is ramping up bird flu testing among people with flu-like symptoms. Identifying infections early allows for better containment strategies and helps track any emerging threats.

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Pets remain vulnerable -

Cats are especially at risk of bird flu due to their natural tendency to hunt infected birds. Pet owners should monitor outdoor pets closely and keep them away from sick or dead birds to avoid possible exposure.

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Vaccination efforts -

Some countries, including China and Egypt, have implemented poultry vaccination campaigns to limit bird flu’s spread. But vaccines are not always effective against evolving strains, and there are still ongoing debates about the best strategies for control.

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Preparedness -

While your eggs and meat are far from containing bird flu, it is still a good idea to be vigilant and take other precautions. Flu viruses can evolve quickly, and a more dangerous strain could emerge at any time.

Sources: (National Geographic) (CDC) (CNN)

See also: Coca-Cola recalls drinks amid safety concerns

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