Teenager infected with H5N1 bird flu is in critical condition

Canadian health officials announced Tuesday that a teenager is in critical condition after contracting H5N1 avian influenza of unknown origin.

According to British Columbia Health Officer Bonnie Henrythe child was suffering from acute respiratory distress and was admitted to the hospital on Friday.

The teenager is Canada's first presumed case of H5N1 avian influenza.

“Our thoughts continue to be with this man and his family,” Henry said.

Authorities believe the virus was transmitted through an animal source. However, the teenager was not on the farm or near known wild birds or backyard poultry, which are common sources of the disease.

According to a CBC interview with Henry, the teen had no contact with birds, but had been exposed to a variety of other animals, including dogs, cats and reptiles, in the days before he became ill. Tests on these animals have so far been negative.

Health authorities are also tracing the people the boy came into contact with, but so far no other cases have been identified.

Jennifer Nuzzo, director of Brown University's Pandemic Center, said the situation is “scary.” “It is an absolute tragedy that there are children and teenagers who have become seriously ill with this virus. But sadly, what we know about H5N1 and its ability to cause disease… All things considered, this is not surprising.”

He pointed out that since the late 1990s, when the current strain of bird flu emerged in China's Guangdong province, the fatality rate has been close to 60%. That number is likely an exaggeration, she said, because most of the people tested for the disease are those who went to hospitals and clinics seeking treatment. People with mild symptoms or no symptoms are likely not tested.

Nevertheless, Nuzzo said that while this virus could be “much less deadly than anything we've seen before,” it still remains the same virus that we've seen for so long, including COVID-19. He said it could be far more deadly than previous pandemics.

She said the incident was concerning for three reasons. The first is the severity of the teen's illness. Second, “we don't know how this teenager got infected.” Her third concern is how government authorities are dealing with the outbreak, which she said is likely to “continue to spread from animals to humans without proactive measures.” “I'm doing it,” he explained.

He said the virus may not ultimately become more virulent or more efficient at moving between people, “but we can't wait for that possibility to happen.” I don't think so.''

Since the virus appeared in wild birds in North America in 2021, most cases of infection in humans have remained mild. Since 2022, there have been 47 human cases in the United States, including 25 in dairy workers, 21 in poultry workers, and one in Missouri where the source of infection has not yet been identified.

However, recent research from the U.S. Centers for Disease Control and Prevention shows that the virus is more prevalent among dairy workers than previously thought. When 115 dairy workers in Michigan and Colorado were tested for antibodies, eight tested positive for the disease, or 7% of the study population. This indicates that the worker has not reported illness or is asymptomatic.

Nuzzo also pointed to recent research. Published in Nature (led by Yoshihiro Kawaoka)H5N1 experts at the University of Wisconsin-Madison believe that the virus first reported in a dairy worker in Texas has acquired mutations that make it more severe in animals, while also allowing it to spread between animals through airborne transmission. It was shown that it was possible to move more efficiently. Breathing.

When Kawoaka exposed ferrets to this virus isolate, 100% died. Additionally, the amount of virus they were initially exposed to didn't seem to matter. Even very low doses caused death.

Kawoaka said in an interview with the Times that the mutations seen in this particular isolate have appeared elsewhere in past occurrences of birds and mammals, and “in that sense, it's a very orthodox mutation.” Ta.

The strain isolated from the Canadian teenager has not yet been genetically sequenced, so it is unclear whether it carries these mutations or others.

Fortunately, the isolate has not been seen since infecting a dairy worker in Texas. It is unclear why the worker did not show more severe symptoms.

However, there are some hypotheses.

Kawaoka's research shows “inefficient replication” of the virus in human corneal cells. If a worker exposes their eyes to contaminated milk droplets or rubs their eyes with contaminated gloves, the virus may be stalled and multiply as it would if the worker were exposed through inhalation. I can't do that.

Nuzzo said there are other theories, such as one that people exposed to the 2009 H1N1 pandemic may have developed some level of immunity to the “N1” part of the virus, which may simply be the case. He emphasized that this is a hypothesis.

The other traces back to a person's first exposure to influenza.

There's a scientific hypothesis called “protoantigenic sin,” which states that a first exposure to a particular virus “may kind of set the tone” for a person's immune system going forward. suggests. So, this worker's first flu exposure, his immune system has the necessary defenses to suppress H5N1.

“There are far more questions than answers at the moment. So, while there are a lot of interesting hypotheses as to why recent cases have been mild, there are many indications that this virus could be very deadly. There is simply not enough evidence to simply throw away more than 20 years' worth of evidence about this virus,” Nuzzo said.

With human flu season in full swing, Nuzzo said it's critical that people do what they can to prevent the spread of the disease.

He said both seasonal influenza and H5N1 vaccines should be offered to dairy workers.

Unfortunately, she said, “our surveillance efforts to detect on-farm outbreaks, while improving, still fall short of what we even need to know about these outbreaks.” “I haven't.”

In the meantime, you should have vaccines and antivirals on hand.

“The news of a very serious human case of avian influenza is a huge wake-up call and should immediately mobilize efforts to prevent further human pandemics,” said Farm Forward Executive Director Andrew Decoris. he said. “We could have prevented the spread of avian influenza in poultry farms across America, but we didn't. We could have prevented the spread of avian influenza in dairy farms, but we didn't. did.”

“Factory farms, notorious for raising billions of sickly animals in filthy and cramped conditions, are a contributing factor to the emergence and spread of viruses like avian influenza (H5N1),” Decoliolis said. said in a statement. “We are now on the brink of another pandemic, and the agencies charged with regulating farms and protecting public health are outpacing the spread of the virus.”

As of Wednesday, 492 dairy herds across 15 states were infected with H5N1. More than half, 278, live in California. Two pigs were also infected in Oregon.