When a chicken flu virus struck a main poultry farm in Russia earlier this yr, it was a reminder that the coronavirus inflicting the pandemic was not the one harmful virus on the market.

The authorities shortly examined the birds and moved into excessive gear, killing 800,000 chickens, disposing of the carcasses and cleansing the farm to cease the potential unfold to different rooster farms. But they have been additionally involved for people.

They examined the birds and sequenced the virus, figuring out that it was the H5N8 pressure of avian flu, extremely harmful to each wild and home birds. It is established in Asia and has been more and more inflicting lethal outbreaks in birds in Europe. H5N8 viruses have infected some poultry flocks in the United States, but the viruses come from a totally different although associated lineage of virus, distinct from the present H5N8 viruses in Asia and Europe. Flu viruses mix and mutate continuously in unpredictable methods.

In the brief interval from Dec. 25, 2020, to Jan. 14 of this yr, more than seven million birds were lost to H5N8 outbreaks in Europe and Asia. Europe alone had 135 outbreaks amongst poultry and 35 amongst wild birds. Of course, to put the numbers in context, people devour about 65 billion chickens every year, and one estimate places the variety of chickens on the globe at anyone time at 23 billion.

As damaging as H5N8 has been to birds, it had by no means contaminated individuals. Until February. The Russian well being authorities additionally examined about 200 of the individuals concerned within the cleanup of the farm in Astrakhan, utilizing nasal swabs and later blood exams for antibodies. They reported that for the first time, H5N8 had jumped to people. Seven of the employees appeared to have been contaminated with the virus, though none of them grew to become sick. Only a type of seven circumstances, nonetheless, was confirmed by genetically sequencing the virus.

Nonetheless, the potential hazard of the brand new virus and its soar to people set off alarm bells for Dr. Daniel R. Lucey, a doctor and a specialist in pandemics at Georgetown University.

To Dr. Lucey, nobody else appeared to be taking the an infection of people with H5N8 as “of any concern.” He added, “I think it’s of concern.”

Other scientists stated they weren’t as apprehensive.

Dr. Florian Krammer, a flu researcher on the Icahn School of Medicine at Mt. Sinai, stated he was extra involved about different avian flu viruses like H5N1 which have already proven themselves to be harmful to individuals. Another avian influenza virus, H7N9, infected people for the first time in 2013. There have been more than 1,500 confirmed cases and more than 600 deaths since then. Since 2017 there have been solely three confirmed circumstances and the virus does not jump easily from person to person.

It is all the time doable that any virus can evolve human-to-human transmission, in addition to change into extra harmful. But H5N8 would have each hurdles to soar. Compared to different viral threats, Dr. Krammer stated, “I’m not worried.”

Dr. Richard J. Webby, a flu specialist on the St. Jude Graduate School of Biomedical Sciences and director of the W.H.O.’s Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, stated that the entire H5 viruses are of concern as a result of a few of them have contaminated and killed individuals. But, he stated, “They all have the same sort of binding capacity to human cells, which is limited,” he stated. Flu viruses use a barely totally different manner to connect to cells in birds than to cells in people and being good at one often means not being good on the different.

Dr. Webby additionally stated that whereas seven infections would definitely be of concern, just one an infection has been confirmed. The exams of the opposite six concerned nasal swabs and blood antibody exams. In individuals with no signs, he stated, nasal swabs can merely point out that that they had breathed in virus. That wouldn’t imply it had contaminated them.

Blood antibody exams even have a potential for error, he stated, and will not be in a position to distinguish publicity to one flu virus from one other.

Nor did he see any scientific foundation for suggesting that H5N8 is extra doubtless than another chicken flu to evolve human-to-human transmission. But any virus may evolve that capability.

Dr. Lucey stated that he was heartened to see that the U.S. Centers for Disease Control and Prevention had ready a candidate vaccine for H5N8 before it had infected humans. Candidate vaccines are merely first steps in planning for potential issues, and haven’t been by means of any testing. They exist for a lot of viruses.

“Humans should be routinely tested those for the virus, right at the time of the outbreak in birds,” Dr. Lucey stated. He favors the protocol adopted in Astrakahn, and argues that for any outbreak amongst birds, public well being authorities ought to check people who find themselves uncovered to sick birds with nasopharyngeal swabs and an antibody check, adopted by different antibody exams a few weeks later.

An upcoming editorial within the journal Travel Medicine and Infectious Disease additionally takes up the Astrakahn incident and requires elevated monitoring of all H5 viruses.

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