Will Humans Be Affected by the Bird Flu Virus Discovered in Cow Milk Supplies?

Most researchers maintain that even if a human were to be infected by the bird flu virus, there is scant probability of widespread contamination, according to tests conducted thus far. Paris: While experts assert that the risk of food contamination is minimal, the detection of avian flu virus remnants in pasteurized cow milk in the […]

Most researchers maintain that even if a human were to be infected by the bird flu virus, there is scant probability of widespread contamination, according to tests conducted thus far.

Paris: While experts assert that the risk of food contamination is minimal, the detection of avian flu virus remnants in pasteurized cow milk in the United States has sparked worries regarding potential human transmission of the disease.

In a notable investigation, US officials announced on Tuesday that they discovered traces of the avian flu virus in the cow milk supply. However, the samples were deemed to present minimal risk to human health.

What information do we currently possess?

Officials stated that a human contracted Highly Pathogenic Avian Influenza (HPAI) with moderate symptoms, and the virus had been transmitted among dairy cattle herds throughout the United States.

Amid the ongoing outbreak, millions of chickens have succumbed to the H5N1 strain of Highly Pathogenic Avian Influenza (HPAI), while the infected cows have not experienced severe illness.

As per the US Food and Drug Administration, virus particles were detected in “milk from affected animals, in the processing system, and on the shelves” during a comprehensive nationwide evaluation.

Despite the virus being rendered inactive by the heat of the pasteurization process, the samples underwent testing using a quantitative polymerase chain reaction (qPCR) assay, which is capable of detecting residual genetic material from the infection.

What was the reason behind its occurrence?

The avian flu strain A/H5N1 emerged in 1996, but since 2020, there has been a significant rise in the number of bird populations contracting the virus and an increasing number of mammals have also been affected.

Experts were surprised when cows and goats were included in the list in March, as until that point, it was not believed that these animals could be affected by this specific virus.

“In the United States, a new H5N1 virus has intermingled with local viruses, and has the ability to multiply extremely rapidly in a cow’s udder,” stated Jean-Claude Manuguerra, who leads the Pasteur Institute’s department focused on infection risks and environmental concerns in Paris.

Nevertheless, while the ongoing outbreak of H5N1 has resulted in the deaths of millions of poultry, affected cows have not experienced significant illness.

Risk of a pandemic?

Most researchers think that even if the avian flu virus infects a human, there’s a slim chance of extensive spread based on current test results.

“Is the fact that virus traces have been found in cow milk worrying? No, although the fact that another animal is susceptible to contamination by this virus is not good news,” stated Virologist Bruno Lina, based at Lyon Hospital in southeast France.

“There’s a risk of random cases, in animals or humans. But we’re not seeing any major mutation of the virus that would lead to a greater pandemic risk than three or four months ago,” he stated.

Risk to human well-being?

A person who worked on a dairy farm in Texas and had contact with cattle in April was recovering from avian flu, as reported by US authorities.

Following direct contact with a cow, the individual only experienced a minor eye infection, and the symptoms were insignificant.

“What we know is that the virus can cause in humans an infection in two specific places: an eye infection — which is mild — or in the pulmonary alveoli, the deepest parts of the lung,” Lina stated.

In such cases, the infection could potentially lead to fatalities; of the roughly 900 documented cases of H5N1 in humans by the World Health Organization over the past two decades, around half have ended in death.

The risks are virtually negligible when consuming pasteurized milk, even if traces of the virus are detected.

“Pasteurisation destroys the virus even if it doesn’t eradicate every trace of its presence,” Lina stated.

How about unpasteurized milk?

While some countries, such as France, appreciate consuming raw cheeses, experts emphasize that the production process adheres to strict hygiene regulations.

“Has anyone ever been exposed to non-pasteurized milk contaminated by H5N1, and developed an infection by the normal means of consumption, the mouth or digestive tract? It’s never been demonstrated,” Lina stated.

Moreover, according to Manuguerra, the latest virus strain identified in the US is distinct from those already present in Europe.

Additionally, he mentioned that there have been no cases of H5N1 infections detected in French cows, for example.

“The warning has been sounded, there is extra vigilance — and these viruses can mutate so rapidly that you have to keep an eye on them,” he continued.

“But I think that consumers should not be worried.”