A terrible trail has been left in its wake: since October 2021, avian flu has killed 15 million domestic birds and forced the killing of an astounding 193 million more. After rapidly spreading to bird populations in South and Central America, the rogue virus has moved from Europe and Asia to North America.
Also, it is no longer just for birds. Grizzly bears in Nebraska and Montana, a red fox in Montana, six skunks and raccoons in Oregon, a Kodiak bear in Alaska, and other wild mammals are among those in the United States that have either died from or were culled due to avian influenza epidemics.Then, in January, the World Health Organization (WHO) revealed the first case of avian influenza in South America, which was found in a little girl in Ecuador.
These outbreaks are resembling the opening minutes of a pandemic film, with the scene-stealer taking place in Galicia, Spain, in October. There, the mortality rate in a 50,000-animal mink farm increased week by week. Avian influenza was considered a possibility following a recent outbreak on the seashore close to Corua that resulted in the sickness or death of 27 seabirds. Sequencing, however, uncovered something more sinister: a mutation that had allowed the first-ever widespread instance of direct mammal-to-mammal bird flu transmission.
In the past year, there have only been five human instances of avian flu. Yet, the WHO reports that the fatality rate for H5N1 avian influenza cases in humans in the past was 53%.
The virus is causing a shortage of poultry, killing large numbers of wild birds, and increasingly spreading to mammals, which raises the following general query: Could bird influenza develop into a full-fledged pandemic from an ecological catastrophe?
The quick response: According to scientists, there is currently little chance of widespread bird flu transmissions to, and among, humans. The next pandemic could be caused by the rapidly spreading avian influenza infection, which, if it spreads to people, could have a fatality rate that is significantly higher than COVID-19.
The mafia takes over Avian influenza is a general term for a number of flu types. The H5N1 strain is the one that often causes worry, with each letter and number designating a different type of bonding protein that the virus carries on its surface. But one must go back to China in the late 1990s to fully comprehend H5N1 and put its recent spread into context.
H5N1 first appeared in Chinese poultry industry in 1996, according to Isabella Monne, a researcher from Italy's Istituto Zooprofilattico Sperimentale delle Venezie who recently examined the mink outbreak in Galicia. High populations and crowded living conditions favored the emergence of more virulent strains, which in 2005 spread to wild bird populations.
Because of this, the virus was able to spread over Asia, Europe, and the Middle East. 468 human cases, mostly among poultry workers, led to 282 fatalities between 2003 and 2009. The number of host species and populations increased dramatically from 2010 to 2020. In total, 457 people have died from the virus in the past 20 years.Later, in 2021, a leading family or clade of H5N1 variations carried out a mafia-like conquest. The 2.3.4.4b clade had moved to Canada and the US by the end of 2021 in addition to accounting for the great majority of new cases in Europe, Asia, and the Middle East. The clan also relocated to Central and South America in 2022.
According to Kaitlin Sawatzki, a molecular virologist and coordinator of animal monitoring at Tufts University, the rise in mammalian infections is not unexpected given the surge in outbreaks among domestic and wild birds. She described the overflow to mammals as isolated events.
H5N1 is predominantly a gastrointestinal sickness that spreads by feces in birds, according to Sawatzki.
According to William Schaffner, a professor of medicine in the Division of Infectious Diseases at Vanderbilt University, the virus must bind to receptors in the lungs in order to infect people. These receptors are difficult for the virus to connect to. Only poultry workers who breathe in contaminated faecal dust often contract the infection because of this forced adaptation to reproducing in the lungs. Also, it explains why there have never been numerous instances of transfer from mammal to mammal.
prior to Galicia.Minks, seals, and…people?
According to Monne, the Galician minks were most likely exposed to wild birds after H5N1 epidemics in nearby bird populations. Monne herself contributed to the discovery that the virus altered the PB2 gene in the large population of mammalian hosts.
The PB2 mutation is known to improve the activity of an enzyme involved in viral replication in mammalian cells, though it is yet too early to say how much this contributed to the virus' jump to minks. The H1N1 swine flu strain that produced the 2009 pandemic, which claimed the lives of between 123,000 and 203,000 people globally, also carried the same mutation.
According to Wenqing Zhang, the head of the World Health Organization's (WHO) worldwide influenza program, "the mutation is a signal that this virus is trying to overcome the barrier between species and adapt to the mammalian population."
The mink case, in Sawatzki's opinion, is not definitely an instance of persistent transmission. While being alarming, the PB2 mutation prevented the virus from spreading to humans or other mammals. It led nowhere. No employees had the infection. They killed the minks. The viral genome underwent careful analysis and sequencing.
She finds more alarming the mass extinction of harbour seals that occurred off the Maine coast of the US last year as well as the more recent deaths of 2,500 seals off the coast of Dagestan, Russia. She said that seals are not exposed to or ingest large enough numbers of birds to account for their high infection rates.
The implication is that although it hasn't been proven, the seals may have a different, as of yet undiscovered, pathway of infection in a wild population that is difficult to monitor or cull.
No protection
What does this all entail for the health of people?
Humans may contract the H5N1 respiratory infection either directly from an animal or indirectly through person-to-person transmission. The latter has only ever been suspected in a very tiny number of completely unverified occurrences, the most recent of which occurred ten years ago.
Also, a lot of the recent avian flu headlines have focused on stories of effective monitoring. Zhang claims that for more than 70 years, the WHO has been keeping tabs on influenza outbreaks and viruses. The organization actively sequences variants that appear throughout the world, monitoring the emergence of mutations of concern. This capability has only gotten better since the COVID-19 pandemic.
The WHO's Pandemic Influenza Preparedness Framework requires that a part of any vaccinations produced be contributed to the organization in the event of an epidemic. Similar to this, stocks of already available antivirals would probably be reasonably effective against an outbreak.
Pandemic H5N1 risk is not now very high. Yet, Zhang predicted that "there would be another influenza pandemic" at some point in the future. The repercussions could be severe if avian influenza is the cause of that pandemic.
The complete lack of protection to the virus is the adverse effect of H5N1 viruses infrequently infecting people, according to Zhang. Hence, if the virus did develop a reliable method of human-to-human transmission, or much worse, between humans, it would very surely result in a pandemic.
And the mechanism for that evolution is easily accessible.
The genome of influenza viruses is eight segments long. Each segment has the potential to reassort, or exchange genes, with other influenza viruses present in a host. This makes minks and swine, which are susceptible to acquiring human, swine, and avian influenza viruses, potential mixing bowls, Schaffner told Al Jazeera.
This genetic rearrangement could produce a lethal new virus with H5N1's virulence and mortality as well as the receptors to precisely target people in, let's say, a pig infected with a human-associated flu virus and an avian influenza virus at the same time.
Currently in crisis
Schaffner estimated that it would take six to seven months to develop a completely new vaccine. Antiviral supplies already on hand would probably be used up fast, he said. Hence, lockdown measures would likely be used if the avian flu that is sweeping the globe does cause a pandemic among people in order to purchase time for a vaccine.
Schaffner added, "COVID has informed us about the outcomes of behavioral therapies. We experienced a season with nearly no influenza "when we were socially withdrawing and all donning masks" during lockdowns.
Following COVID-19, people are skilled at distancing techniques. Of course, a jaded public could be reluctant to support another lockdown. However, Schaffner thinks that as casualties start to mount, people will probably toe the line, delaying the development of a potential avian influenza pandemic given the high mortality of historical H5N1 outbreaks.
present-day crisis
Schaffner predicted that the creation of a brand-new vaccination will take six to seven months. Existing antiviral supplies will likely run out quickly, he predicted. In order to buy time for a vaccine, lockdown measures would likely be implemented if the bird flu that is sweeping the globe does spread to humans.
"COVID has informed us about the results of behavioral therapy," Schaffner continued. During lockdowns, "we were socially withdrawing and donning masks," we had a season with almost no influenza.
People are adept at distancing methods after COVID-19. Naturally, a weary populace could be reluctant to endorse yet another lockdown. Given the high mortality of previous H5N1 outbreaks, Schaffner believes that as casualties start to mount, individuals will likely toe the line, delaying the emergence of a potential avian influenza pandemic.
H5N1 is already a problem in terms of nutrition, the economy, and the environment. The globe is on alert due to the high-stakes threat of a human bird flu pandemic, notwithstanding the current low risks.
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