Highly pathogenic avian influenza is devastating to birds, and humans could be next

Still suffering from Pandemic Fatigue? Then you may not yet know about a virus that has gripped the nation. It resulted in over 50 million deaths in 2022 alone, but don’t panic just yet. So far, these deaths have only affected birds in the United States. Highly pathogenic avian influenza A (HPAI), a particularly thorny form of the H5N1 flu, is highly contagious among birds and can have a nearly 100 percent fatality rate for the winged animals, according to the National Emerging Special Pathogens Training and Education Center.

Bird flu does not spread to humans very often. The US reported its first human case of HPAI last April in a person involved in the culling of birds at a farm where H5N1 had been confirmed to infect the poultry. According to the World Health Organization, the patient was isolated and recovered after treatment with antivirals.

But under the right conditions, some spillover cases can quickly become a public health problem of epidemic proportions. Ebola is one example: since it was first described in 1976, the virus has intermittently spread to humans in regions where it is endemic. However, the worst outbreak of the virus happened in 2014, when it spread to more than 28,000 people in West Africa, killing more than 11,000 people.

Recent reports that HPAI has infected and killed thousands of sea lions in South America have researchers concerned that the virus could one day spread between humans or participate in a dangerous melting pot in a mammalian host.

“We’ve been thinking a lot about this strain lately because it can potentially be a zoonotic disease” that’s transmitted from animals to humans, Adel Talaat, a microbiologist at the University of Wisconsin-Madison, told The Daily Beast. Talaat has been working on developing an avian flu vaccine that could one day be given to poultry.

Wait, are we vaccinating birds now??

The US hasn’t vaccinated poultry against bird flu, but researchers like Talaat think we should start. He and his team are working on nanovaccines – injections in which active components are very small to better trigger an immune response. Its vaccine is given via a spray rather than an injection to vaccinate large numbers of birds more quickly.

It is important to note that the goal of vaccinating birds is not the same as it is for humans. Farm birds to be vaccinated are only a portion of the world bird population, so the goal of vaccinating them is more to minimize the economic costs associated with HPAI and bird culling than to achieve any meaningful form of flock immunity. Methods for vaccinating wild bird populations are not currently practical, Talaat said, prompting researchers to focus their efforts on what they can feasibly control.

Cases of sea lions could be a sign for the future

Recent reports of sea lions transmitting HPAI to each other and dying from the disease are more alarming to humans than it might sound. Researchers typically view zoonotic diseases in multiple stages, and a number of mutations in the influenza virus are necessary for the pathogen to spread between people rather than just occasionally from birds. That the virus easily infects one species of marine mammal means it’s not as far from spreading between humans as we’d like to believe.

A second concern associated with infection of non-avian animals with HPAI is the risk of antigenic cross-over. The surface proteins of influenza viruses are recognized and used by our immune system to produce appropriate neutralizing antibodies. But over time, these proteins change to the point where they are no longer recognizable. This process can also occur abruptly when two subtypes of influenza virus meet in a single host. Antigenic shifts occurred in particular to bring about the 2009 “swine flu”. “If there is a shift, most people will have little or no immunity to the new virus,” according to the Centers for Disease Control and Prevention.

The antigen shift is a real threat that’s becoming more likely as the virus continues to infect sea lions, Talaat said. Monitoring is all researchers can do at the moment: “We have to pay attention – it’s the best we can do at this point,” he said.

What happens if the virus jumps? am i at risk

“We have to be ready, and by that I mean we have to be ready with a new vaccine,” Talaat said. “These events are happening due to the continuous evolution of the virus and we have no control over it. We have no fences preventing us from coming into contact with wild birds.”

The CDC has produced a vaccine candidate that could be used to make a vaccine for humans if needed. Countries would also need to be armed with a surplus of existing antiviral drugs. Aside from taking normal precautions about our hygiene and limiting the time we spend with birds, there’s not much you or I could do, Talaat said.

So how concerned should I be?

Right now it’s a watch-and-wait scenario.

“Honestly, I’m not worried about us in the United States,” Talaat said. Relatively few people are directly involved in handling birds, and the US does not have outdoor animal markets, which play a key role in initiating and spreading zoonotic outbreaks. However, that risk assessment would change if the virus were found to spread between people. “That would definitely be a different story,” he said.

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