Montserrat Agüero, biologist: "We have never seen so many outbreaks of bird flu, now we have 50 times more outbreaks"

The biologist Montserrat Agüero put the world on alert just over a month ago.

Her analysis of an outbreak of bird flu at a Spanish mink farm showed that the virus most likely reached the farm via seagulls and there was able to be easily transmitted from mammal to mammal.

It had never happened.

The World Health Organization's new chief scientist, British doctor Jeremy Farrar, has warned that this is exactly how a "devastating flu pandemic" can start in people.

Agüero is the head of animal health at the Central Veterinary Laboratory of the Ministry of Agriculture, an international benchmark in the control of threatening diseases, in the Madrid town of Algete.

The A(H5N1) avian influenza virus has been circulating for almost three decades, but never as long as now.

Europe suffers the most devastating epidemic in history, with more than 50 million poultry slaughtered in one year.

Many American countries are on high alert.

The good news is that the virus fails to multiply in people's throats and only rarely manages to colonize the lungs.

Barely half a dozen cases have been detected worldwide since 2020. The bad news is that it can mutate and humanity has no defenses against this virus.

Since 2003, some 870 human cases have been reported and more than half have died.

The last one was an 11-year-old girl, who died in Cambodia this Wednesday.

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11-year-old girl dies of bird flu in Cambodia

The mink outbreak occurred on a fur farm in Carral, a Galician town near A Coruña.

The facility's 52,000 animals were immediately euthanized.

A couple of weeks ago, a lethal outbreak in sea lions in Peru once again set off the alarms.

Scientists do not rule out that it is the first time that the bird flu virus is transmitted between mammals in nature.

Agüero, born 60 years ago in the Segovian village of Aldehuela del Codonal, receives EL PAÍS in her office, next to the door of the high-security laboratory where they also diagnose other dangerous diseases that spread from animals to people, such as West Nile fever.

Ask.

His study suggests that the bird flu virus was transmitted from mink to mink on the Galician farm.

It is safe?

Answer.

There can be no absolute confirmation.

What indicates that there was transmission from mink to mink is how the infection process was on the farm.

It started in a localized point and slowly spread to the rest of the facilities, eventually affecting the entire farm.

This seems compatible with a contagion process from the affected mink to the following mink.

Different rows of animals were infected.

Q.

Is there any other hypothesis, apart from the contagion from mink to mink, that could explain this outbreak?

R.

It is difficult, because if there had been a simultaneous transmission through the feeding of the minks it would have been something much more general in the different points of the exploitation, but it was not like that.

And that hypothesis that it was through food seems clearly ruled out due to the origin of the food used.

They came from local chicken farms where there have been no outbreaks of bird flu.

Photograph distributed by the Franz Weber Foundation of seagulls at the Carral mink farm.Carmela Fernández

Q.

The Franz Weber Foundation published some photographs of the mink farm, with dozens of seagulls perched on the roof.

It does not seem ideal from a biosecurity point of view.

A.

No, of course.

These facilities are semi-open.

The minks are in cages, but there are open areas.

Contact with wild birds is possible.

Q.

Have you sequenced the complete genome of the mink virus?

R.

In the European reference laboratory, in Italy, they have sequenced four samples from four mink.

They are not absolutely identical, they have logical differences.

When the virus passes from one to another, mutations appear.

Regarding whether they are related to foreign viruses that could be the origin of the outbreak, among the many detections of flu in wild birds, a virus very similar to that of minks has been found in a Pontevedra gull.

The minks are in cages, but there are open areas.

Contact with wild birds is possible

Q.

In your analysis of the outbreak, you warn that mink farms are "shakers" of viruses.

Because?

A.

Mink is susceptible to bird viruses and human viruses.

So, if there is a coinfection in an animal, combinations of both viruses or drastic changes could occur that could generate viruses with other infection capabilities.

Q.

The Dutch virologist Marion Koopmans, who traced the origin of the covid for the World Health Organization, reacted to the outbreak in mink with a phrase: "We are playing with fire."

Do you think we are playing with fire?

A.

It is not something that I can say from my experience or my knowledge of these viruses.

I think it is very important to convey that there are very powerful surveillance and control systems for these dangerous pathogens, which is why we have detected this.

In the event of any respiratory symptoms and increased mortality, a diagnosis is made and action is taken quickly.

Q.

A 9-year-old girl from a village in Ecuador tested positive for bird flu on January 7th.

She lived with chickens and spent a couple of weeks with severe symptoms without anyone realizing that it was bird flu.

In Spain there may be great surveillance networks, but the situation is different in rural areas of Ecuador, Vietnam, China... Are you worried about the lack of surveillance in other countries?

R.

It worries me like any other person, but I can't comment on what I don't know.

Surveillance systems in Spain work.

Anything that arises is being watched and controlled.

Three technicians inspect the carcass of a sea lion in the Paracas National Reserve, in Peru, in January.SERNANP

Q.

Preliminary analysis of the avian influenza outbreak in Peruvian sea lions also suggests that there may have been mammal-to-mammal transmission.

On a beach, 100 sea lions appeared floating.

It is difficult to explain without transmission from one to another.

A.

Yes, they are indications that transmission could have occurred between them, but there are more doubts there, because their feeding points were not controlled [as they were at the mink farm].

There are other hypotheses of simultaneous contagion, such as the consumption of infected bird remains, for example.

Q.

Are you concerned that there is transmission of bird flu between wild mammals in Spain?

A.

We have not received samples from wild mammals in which high mortality has occurred.

Q.

So, for the moment, bird flu in Spain is only in birds.

R.

In birds, yes, but the novelty this year is that the virus is circulating much more, not only in Spain, but throughout the world.

It is circulating even in summer, when it usually did not circulate.

We've had outbreaks pretty much all year long.

Avian flu is circulating even in summer, when it usually did not circulate

Q.

Can the epidemic disappear on its own?

Or is bird flu already going to be endemic?

A.

Influenza has circulated in wild birds forever.

What there has not been at other times is such numerous outbreaks.

I don't know what the future of this will be.

Q.

Is it the record of circulation of avian flu since there are records?

A.

In my experience since 2008 we have never had this level of outbreaks, of course.

Q.

What was normal?

R.

_

Spain has had very, very, very sporadic cases until 2020. Between September 2020 and September 2021, three outbreaks were detected in wild birds.

Between January 4, 2022 and January 18, 2023, 149 outbreaks in wild birds have been reported.

There are 50 times more outbreaks, plus another three in zoos and 37 in poultry farms.

Q.

You highlight the finding in mink of viruses with the T271A mutation, which already appeared in the 2009 swine flu pandemic virus. What does this mutation imply?

A.

My colleagues from the European reference laboratory [the Experimental Zooprophylactic Institute of Venice, in Italy] are the ones who have described this mutation and its implications.

They comment that it favors the virus infecting mammalian cells.

Q.

Avian influenza A(H5N1) viruses are very awkward at infecting the upper respiratory tract of humans, but rarely do they infect the lower respiratory tract.

A.

Yes, indeed.

Avian influenza viruses are poor at infecting mammalian cells, but changes may occur that make them more capable of infecting.

Q.

The Dutch virologist Thijs Kuiken wondered in this newspaper: "If he has managed to go from mink to mink and from sea lion to sea lion, why won't he go from human to human?"

A.

The virus that we have described in mink does not contain the characteristic and necessary mutations to infect humans, according to our colleagues at the European reference laboratory, who are experts on the subject.

Does not have them.

And another very important thing is that at no time was the presence of the virus detected in the workers of that mink farm.

They have been monitored and semi-quarantined and there have been no cases.

Q.

Mink farm workers are required to wear face masks since the covid pandemic.

A.

Yes, the masks have probably prevented any presence of the virus in the workers.

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