People have passed swine flu to pigs at least 370 times over 12 years in the US. Better understanding how the virus behind the disease moves between humans and pigs could help to reduce infections and ensure vaccines stay effective.

Swine flu is the common name for a condition that originated in pigs. It is caused by a type of influenza A, known as H1N1, of which a variant called pdm09 led to an outbreak in people in 2009. Since then, the variant has lingered in pigs and infected a small number of people, with some recorded cases of transmission between the two.

at the US Department of Agriculture and his colleagues wanted to investigate how pdm09 has spread since 2009. They analysed genetic sequences of all the H1N1 virus samples collected in people and pigs in the US between 2009 and 2021. Of these, 12,823 human and 1112 swine samples were of the pdm09 strain.

Viruses evolve quickly in a host’s body and often develop specific traits in different species, says Anderson. To assess which of these samples were a result of transmission between the two species, the researchers looked at how similar the samples were to each other. If one version of the virus in a person looked reasonably different to versions in other people, they assumed it was passed by a pig. Conversely, if a version of the virus in a pig looked different to those in other pigs, they assumed it was passed by a person.

From this, the researchers estimated there were 370 cases of human-to-swine transmission and 17 cases of swine-to-human transmission over the study’s 12-year period, with most of these probably occurring due to farming. However, the true number may be higher as not all infections lead to ill health and can therefore go unreported, says Anderson.

The virus also appeared to evolve particularly rapidly in pigs and continued to circulate in these animals. Vaccines against swine flu can become less effective due to these evolutionary changes, says Anderson.

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Between 2020 and 2021, during the height of the covid-19 pandemic, cases of pdm09 fell in people but continued to circulate in pigs as a carryover from infections in these animals from previous years. This suggests it is possible to reduce the interspecies transmission of swine flu if proper control measures are taken, says at the University of Bergen, Norway.

“We have to understand all the components associated with the transmission of the viruses between different hosts,” says Anderson. “Hopefully if we do that, we could improve animal health and human health.”

Ferrets fight flu

Journal reference: Crucell/Scripps study, ; National Institutes study,

Happy as a pig in litter (Image: Khaled Desouki/AFP/Getty)

At the height of the 2009 swine flu pandemic, the Egyptian government ordered that all of the nation’s pigs – some 300,000 animals – should be slaughtered. They thought this would help to limit the spread of swine flu in dense urban environments such as Cairo. But the cull had an interesting, if all too predictable, side effect.

Pigs were an unofficial part of the nation’s waste-processing infrastructure. They were tacitly relied upon as a key component of the public sanitation regime, and wiping them out resulted in rapidly growing piles of organic waste in the streets.

When we think of cities, traditionally this brings to mind roads, homes and vehicles. But animals are as much a functional part of the modern city as subways and skyscrapers.

This is the age of animals as infrastructure.

Animal Labour

Chicago’s O’Hare Airport, one of the busiest in the world, recently turned to animals as a workforce for seasonal landscape maintenance. In 2013, the airport added what the Chicago Department of Aviation (CDA) called its .

This motley crew of sheep, llamas, goats and donkeys has since been put to work as a lawn-mowing service. Indeed, the animals have proven themselves to be a cost-effective means for keeping grass and shrubs under control in spaces “that are difficult to maintain with traditional landscaping equipment”, the CDA explained.

Even better, from an aviation safety perspective, it reduces the number of birds nesting near the airport’s runways that could cause a bird-strike.

Unconventional lawn-mower (Image: MIRA OBERMAN/AFP/Getty)

The tactic of using animals in cities to manage or even cull other animals is a surprisingly common one. It is also not without its comedy. In London during the second world war, for example, the UK security service MI5 actually created a special falconry unit for hunting down pigeons feared to be carrying messages to German spies. However, as historian Calder Walton points out in his book Empire of Secrets, the only thing those unfortunate pigeons were guilty of was inspiring paranoia.

Dubai has made falconry a minor but dependable part of its pest-control strategy. Amid the 7-star hotels, artificial islands and supertall skyscrapers, . Elsewhere, falcons are being trained with the help of drones – that is, robots are helping to domesticate animals to work for humans.

Several Californian cities have also picked up on the falconry game, incorporating animals into their urban sanitation regimes. Contractors such as Airstrike Bird Control and Pacific Coast Falconry are hired to put trained falcons to work patrolling everything from vineyards to landing strips and golf courses to parks. Even in the heart of Santa Monica, . Birds are being used to get rid of other birds and all their associated waste – not to mention any talon-sized vermin.

What unites these examples is the way in which municipal infrastructure is being expanded to include living creatures. In many ways, of course, this is simply the contemporary urbanization of a practice that goes back millennia. However, the ensuing juxtapositions – of 21st-century landscapes and cities being maintained not by high-tech machines or by specialty equipment but by neo-medieval groups of trained animals – can be quite jarring. Animal labour is once more becoming an explicit component of the modern metropolis, as much a part of the city as subway cleaning crews or distant landfills.

In fact, as New York City discovered after the wreckage of Hurricane Sandy, animal labour had actually been humming away all along, unseen but no less vital.

Insect assistants

In the aftermath of catastrophic flooding, scientists were keen to learn how Hurricane Sandy might have affected the birds, insects and rats of New York City. A team led by entomologist Elsa Youngsteadt at North Carolina State University in Raleigh found that these creatures were far more resilient than had been expected. Indeed, they were thriving, consuming organic waste and discarded food at a stunning rate.

Insects along a single stretch of Broadway in Manhattan were found to be responsible for consuming as much as Arthropods – a group that includes spiders, ants and millipedes – are the great unacknowledged garbage disposal of New York City.

Nature’s waste disposal crew (Image: Steve Cicero/Getty)

Taking the pigs out of Cairo – or the ants out of Manhattan – is, in some senses, equivalent to a refuse-collector strike.

In recognising this critical infrastructural role, however, we must also recognise the near certainty that simply cohabiting with other animals may not be enough for the sheer scale of our urban needs. Instead, it is highly likely that we will soon engineer whole species specifically to function as permanent parts of our everyday urban infrastructure, and we must be prepared to discuss the ethical implications of this before it happens.

Genetic civil engineering

For US-based science writer , author of , this apparently futuristic vision has already happened. In her book, Anthes takes a long look at the emerging world of engineered animals. These creatures are either biological spectacles to be treated as household pets – genetically modified to glow in the dark, say – or augmented by technology to become living sensors, registering scientifically useful data about their environments. Mosquitos that help protect humans against malaria are already being created, too, making insects a de facto part of our global public health infrastructure.

Technologies such as genetic engineering, cybernetics and cloning will “give us all sorts of ways to make animals more useful to us,” says Anthes. “And the more useful we make animals, the more likely we are to actually use them.” Such technologies are now “allowing us to engineer new beasts of burden,” she says. “In a sense, we can turn new species, which we might never have relied on before, into tools or even service providers.”

Anthes points to the growing use of cyborg insects for search and rescue. This means sending sensor-equipped roaches deep into the rubble of a collapsed building in order to find survivors. But, Anthes suggests, there is no real reason why this insect-provided service could not be useful outside the scope of a disaster scene, becoming both ubiquitous and constant.

Today, for example, we rely on devices such as radon detectors, smoke alarms and seismographs to keep tabs on the built environment, alerting us to possible problems or looming emergencies. But, just as O’Hare Airport partially replaced its lawn-care crew with a herd of charismatic animals, London or New York might turn to insect sensors to infest – and thus study – otherwise unreachable urban spaces. If we need more data, we’ll just send more bugs.

From there, it is only a question of scale and, of course, that business buzzword: optimisation. Think goats bred for more efficient grass digestion used to clear our airports and highways, cyborg falcons engineered for stronger eyesight to replace CCTV and even cyberbugs sent trundling into the streets of Manhattan to reclaim valuable recyclables from our rubbish. The growing temptation will be to turn to engineered animals, rather than to existing equipment or inanimate machines, to perform future urban work for us. This has fantastic environmental benefits – but extraordinary ethical risks.

Ultimately, the question is not if this is going to occur. Animals are already being used as functional components of urban infrastructure around the world. The question is: are we morally and legislatively prepared for a world in which we are building whole creatures – new beasts of burden, as Anthes says – for this very purpose? What will it mean when civil engineering has become genetic?

How worried should we be about the newly created viruses?
Not much at all – and certainly not about either of the claims above. But there might be cause for concern in the way this kind of research is being regulated.

Did Yoshi Kawaoka actually make a copy of the deadly 1918 pandemic virus that evades human immunity and vaccines?
No. The work looked at the potential evolution of a current strain of winter flu.

Kawaoka has told żěè¶ĚĘÓƵ that he was exposing the currently circulating winter flu virus descended from the 2009 swine flu to the immune reactions it induces in people and animals, to see what mutants emerge. “This kind of work has been done for more than 30 years, to help in the selection of vaccine strains,” he says.

Why is such work necessary?
Flu is different from diseases like measles, which – if they don’t kill you – leave you immune for life. You can catch flu again and again because it evolves so fast.

After a particular flu virus has dominated a few winter flu seasons, most people’s immune systems recognise and kill it. At that point, a mutant of that virus will emerge that is slightly different to the original flu. This becomes the new dominant winter flu. This process is called “immune escape” and it is why winter flu is often mild: the virus isn’t very different from the last flu we caught, so we have some immunity – just not quite enough to stop it completely.

Every now and then, though, a new flu breaks out to which most people have no immunity. This is a pandemic, and it is usually more deadly than ordinary flu. The last one was the swine flu pandemic of 2009.

After the initial outbreak a pandemic virus keeps circulating as winter flu, becoming less nasty as more people are exposed and get immunity to it – whereupon it starts producing escape mutants like ordinary flu does. The 2009 virus is now starting to do that.

This constant evolution means the flu vaccine has to be redesigned every year for whatever new mutant comes along. Because it takes six months to make, virologists and manufacturers which viruses circulating this winter are likely to dominate next winter. Since the 1980s this process has been aided by experiments in which the current flu is exposed to antibodies and other immune molecules from people or experimental animals, to see what mutants evolve.

So this work has nothing to do with the 1918 pandemic flu that killed more than 50 million people worldwide?
Both the 1918 flu and the 2009 pandemic virus belong to the same family of flu, but they are very different – the 2009 virus isn’t nearly as lethal as the 1918 flu. Itdominated this year’s winter flu season in the northern hemisphere. There is little reason to think the lab-generated mutants will be more virulent.

Kawaoka has done recent work in which he compared viruses resembling it now circulating in birds to a reconstructed 1918 virus, to assess whether it could re-emerge. He concluded it might. That work was criticised for creating dangerous viruses that might not otherwise evolve; it was also done with stringent security measures to prevent viruses escaping.

So is there a problem?
Yes. The problem is not this particular research, but the secrecy that can surround such work. Kawaoka has sent his 2009 virus work to a leading journal, which prevents him from saying much about it before the work appears in print.

And the work was approved by US funding agencies under specific rules for this kind of research, but that process is not open to public scrutiny, even though experts differ on potential risks and benefits.

Both kinds of secrecy have led to misleading public reports. That could make it harder for researchers to do the really important work we need to defend ourselves from flu – which is evolving, whatever we do.

Google may be a master at data wrangling, but one of its products has been making bogus data-driven predictions. A study of Google’s much-hyped has consistently overestimated flu cases in the US for years. It’s a failure that highlights the danger of relying on big data technologies.

Google Flu Trends, which launched in 2008, monitors web searches across the US to find terms associated with flu activity such as “cough” or “fever”. It uses those searches to predict up to nine weeks in advance the number of flu-related doctors’ visits that are likely to be made. The system has consistently overestimated flu-related visits over the past three years, and was especially inaccurate around the peak of flu season – when such data is most useful. In the 2012/2013 season, it predicted twice as many doctors’ visits as the US Centers for Disease Control and Prevention (CDC) eventually recorded. In 2011/2012 it overestimated by more than 50 per cent.

The study’s lead author, of Northeastern University, says the fixes for Google’s problems are relatively simple – much like recalibrating weighing scales. “It’s a bit of a puzzle, because it really wouldn’t have taken that much work to substantially improve the performance of Google Flu Trends,” he says. Merely projecting current CDC data three weeks into the future yields more accurate results than those compiled by Google Flu Trends. Combining the two resulted in the most accurate model of all. Lazer says Google Flu Trends does have promise, especially at predicting flu trends over smaller areas than the CDC takes into account, which could enable individual cities or states to prepare.

Neil Richards, a data and privacy lawyer at Washington University in St Louis, says the study is an important insight into the immense power that the analysis of large data sets has afforded technology companies like Google and Facebook – and why that power is dangerous. “We now have technology companies with power that rivals the state in some respects, and which have much more of an impact on our daily lives,” Richards says. Understanding the failings and the function of technology companies is becoming increasingly important, as they wield ever more power.

, a technology ethicist at Rochester Institute of Technology in New York, says Google Flu’s failures hint at a larger problem with the algorithmic approach taken by technology companies to deliver services we all want to use. The problem is with the assumption that either the data that is gathered about us, or the algorithms used to process it, are neutral. The main concern of tech companies like Google, or data brokers like Acxiom, is to use patterns in that data that can make them money (like where an advert should be placed on screen to maximise the chance that men in Boston aged between 25 and 30 will click it). How they go about that has a huge impact on our lives, and yet we have no idea how it works.

“Algorithmic accountability is one of the biggest problems of our time,” Selinger says. “More and more decisions made about us are computed in processes we don’t have access to.”

Selinger points out that the other areas of life where people make decisions that affect our welfare are much more transparent – we have an opportunity to a fair trial when accused of breaking the law, for instance, and can raise issues with our credit score if we feel it’s wrong. In contrast, a business that finds itself pushed to the second page of Google’s search results or delisted from Google Maps can never know the reason – the algorithms which make that decision are Google’s property.

Unfortunately, the power of Google’s algorithms are hard to substantiate. “We all have some sense of what could really go wrong,” Selinger says. “But when it comes to big data and data brokers and companies there’s only a few of little things on the radar – , for instance.”

The issues are serious enough for President Obama to order a review, led by John Podesta, of the risks big data poses to privacy. The first of three conferences examining the legal, technical and sociological issues surrounding big data .

The more that real-world decisions are based on algorithms, the more important transparency into those processes becomes, Richards says. Already, automated systems determine whether people receive loans or jobs. Algorithmic analysis may be used to determine no-fly lists. The Intercept, drawing on the documents leaked by Edward Snowden last year, has reported that analysis on data held by the NSA has been used to target drone strikes.

“Now that data scientists have achieved a remarkable level of social power, I hope we’ll see them recognising that with that power comes a great degree of professional responsibility, the same way doctors and lawyers and journalists do,” says Richards.

Journal reference: Science, DOI: 10.1126/science.1248506