Emerging Viruses: Monkeypox on the up

Covid continues to rampage, monkeypox is spreading fast, and bird flu has seen its biggest season ever. Why?
28 June 2022
Presented by Chris Smith, Julia Ravey
Production by James Tytko, Chris Smith.


Monkeypox virus


Emerging viral infections go under our microscope this week, including the recent surge in monkeypox, the world's largest bird flu outbreak to date, and learning points from Covid-19. Plus, in the news, the biggest bacterium ever seen, brain training - or brain draining - apps, polio circulating in London, and signs we make friends with people who smell like we do! 

In this episode

Thiomargarita magnifica, a bacterium with an average cell length greater than 9,000 µm that is visible to the naked eye

01:06 - World's Biggest Bacterium

This is not a microbe! At 2 centimetres long, it's bigger than some insects...

World's Biggest Bacterium
Jean-Marie Volland, Lawrence Berkeley National Laboratory


Jean-Marie - When I opened them, they are leaf debris - pieces of dead leaves. Then, on the leaves, you can see white spaghetti-like filaments that are about one centimetre to two centimetres in length, swaying left, and right in the water attached, to the leaf. To give you an idea of the size, they are more or less the same size as a eyelash, most likely the biggest bacteria ever!

Chris - We call bacteria "microbes" because you need a microscope to see them. I mean, they are normally fractions of a millimetre across. This isn't a microbe: it's a "macrobe" I suppose you could say isn't it? Two centimetres!

Jean-Marie -Yeah, you could absolutely say that. They are, they are not fitting the definition of microbes very well. That is for sure. They are about 5,000 times bigger than most bacteria. It is the same thing as if you would discover tomorrow that some humans are five kilometres tall; like as tall as the Mount Everest, for instance. This is how gigantic they are.

Chris - Goodness! And what do these bacteria do?

Jean-Marie -They live happily in the mangrove waters. They feed on sulphur. They grow on the surface of the sediment at the bottom of the mangrove water.

Chris - How did they get that big and why?

Jean-Marie - That, that is a very good question that we have not answered yet . Two hypotheses: the, the first one is that if you are a small bacterium and you are being consumed by other microbes that are feeding on bacteria, if you grow to hundreds or even thousands of times bigger than your predator, then you don't have to worry about being eaten by it, right? And then the second idea is that they live in an environment that is unstable and they need to position themselves in a very specific place where they can extract the chemical energy they need for growing. And if they are bigger, they can probably better access this energy. So there is there are some hypothesis in, in that sense as well.

Chris - Are they definitely just one entity? So if you look at them, it's clearly just one bacterial cell - it's not a big assemblage of them that have all joined together and made a sort of "macro" cell?

Jean-Marie - That is a very good question. And the first part of the answer is yes, it is a single bacterial cell. We have done a lot of microscopic investigation to confirm that. Because there are some other large microbes that can make centimetre-long filaments, but they are composed of many cells. In our case, we prepared these giant cells in a way that we could observe them in their entirety. So we looked at entire cells with microscopes in three dimensions. We never detected any separation that would make the filament a multicellular filament. So we know it is a single cell.

Chris - Have you read its genetic code, because that can often give us clues about how something works and who its relatives are.

Jean-Marie - We have sequenced the genome. Yes. And that allowed us to place them on the tree of life. They belong to a group of bacteria called gamma proteobacteria. They are sitting on the tree of life in a branch that is completely away from the origin of eukaryotes for instance. So we know that they are not at the origin of the complex cells that make our body or, you know, other animals. And we have also some clues on the molecular basis for their extreme size. By reading the genome, we know that it has lost some of the genes that are necessary for bacteria to divide in the classical way. And we know that it has some of the genes that are necessary to increase the size, to elongate the cell, have been duplicated. So they are missing some division genes. And on the other hand, they have multiple copies of elongation genes. So that kind of connects very well with the unusual morphology that we observe.

Chris - And do you know how they have baby bacteria? How do they reproduce?

Jean-Marie - We do know, yes, we that is also a quite unusual way of making baby bacteria, like you said. They grow into these large filaments and at the tip of the filaments, the cell will produce a bud. So they will constrict really just the tip of the filaments. And this constriction will close off completely. And a small piece is gonna detach, find a good spot and grow into a new giant filament.

Chris - Does anything eat them? Have they got enemies?

Jean-Marie - We don't know that. I was discussing that with our collaborator in Guadeloupe just before on this interview. And what they said is that they have looked at other giant sulphur microphones and they, they have analysed their - we could call it - their chemical signature and they try to see if they find this same chemical signature in some of the predators and they could not find it. So they don't have any evidence that, you know fish or small animals in the mangrove are feeding on those giant bacteria. We know that they are not consumed by the classic predators of bacteria, because they are just too big to be eaten by other microbes that would normally feed on bacteria. So we don't know who is eating the giant bacteria!

A person playing crash bandicoot on a smart phone

07:20 - Brain-Training App Impacts Vary

Apps that claim to 'train your brain' may only work in certain groups of individuals

Brain-Training App Impacts Vary
Anja Pahor, University of California Riverside

If you go onto an app store and type “brain training”, you are confronted with thousands of games to download. But while playing for fun is all well and good, devoting hours to a game under the misapprehension that you are boosting your brainpower means you might have been misled. Anja Pahor from the University of California Riverside set out to test who is really benefiting from brain training. And Julia Ravey gave the game designed for their experiments a go…

Julia - So, what I have to do is I'm a little astronaut that's running through the world and I've got to collect gems. I can only collect a gem if the gem that I've seen before it is identical to it, which requires me to keep in my mind what that first gem was. [PLAYS GAME] So now I've got to remember three gems in a row, which is a blue circle, a pink diamond, and a green triangle. So the next gem I come across, if it's not a blue circle, because that's three gems back, I'm not allowed to take it. So the next gem I need to pick up, if it's a blue one, I can pick it up. Yep, blue. The next one needs to be a pink gem. Blue, pink, green, pink. Yep. And if this is green - ah, it's yellow, not going to go for it. I completed the level! So I'm playing this memory recall game, and this is being used in a study to test if brain training games are actually impacting our transferable skills outside the game. Because it's important to differentiate if I'm just going to get really good at this one game, or is it that my memory is actually improving. At the minute, evidence for brain training games being able to increase cognitive skills is still lacking...

Anja - Almost everyone has an app that is mentally challenging. Some of them are for fun, but the claims that some of these apps have made are that you will not only improve on the game or on the app itself, but it might transfer to other areas of your life - so you might be able to focus better at work - this is what scientists call far transfer. This however is somewhat questionable and inconsistent findings have been reported in the literature. We need to be careful when evaluating these types of apps to see what they're promising.

Julia - How have you tried to better understand if these games train our brains?

Anja - We developed an app in our lab and we've been testing for years and we've been running participants in our lab and trying to figure out which features of our working memory training app work in which don't. And we conducted three experiments with almost 500 people and basically repeatedly showed that if someone improves on the main training task, but is not able to perform equally well on the same type of task, but with these different memory objects, then they are unlikely to show improvements in a different context or in a different task. This finding is fairly straightforward, but it can help resolve some of the controversies in the field, which has shown these inconsistent findings regarding the effectiveness of brain training. In our lab, instead of asking the question "does brain training work?" and just averaging over large groups of people, we are trying to figure out how brain training works and for whom.

Julia - And is the opposite of that true as well? So say if someone was good at a word game, and then they had this near transfer being good at another word game, they'd have better far transfer as well?

Anja - Yes, this is what our findings would support. So if they can apply what they've learned to a similar task, then they're more likely to show far transfer as well.

Julia - And do we know who these people are, who have these better transferable skills? Do they have anything in common?

Anja - So we haven't looked at that data yet, but we are planning to examine that in the future.

Julia - So how are you planning to expand your research into brain training games using bigger populations?

Anja - We have recently actually launched a large scale citizen science study that aims to recruit 30,000 individuals. We are including many different training conditions and games, and we will be trying to figure out which types of games work best for which groups of people. And we can only do this when we have a very large and a diverse sample of hopefully thousands of participants.

Julia - And so is the aim in the future to have brain training games that work more on a personalised level? So you can look at an individual and think about what games would work best for them?

Anja - Exactly. We think that that is the future for brain training because there is just no one type of game that will work for everyone. We know that there are substantial individual differences in responsiveness to training, and we really need to take that into account.

To take part in the citizen science study, visit https://bgc.ucr.edu/trainmymemory/?r=bbc

Electron micrograph of the poliovirus. Poliovirus is a species of Enterovirus, which is a Genus in the family of Picornaviridae, and is an RNA virus.

Polio Transmission in London
Wendy Barclay, Imperial College London

This week there were alarming reports of polio virus, which can cause paralysis, circulating in London. The detection was made by sampling sewage from Becton. This is worrying because, for 20 years, the UK has enjoyed “polio elimination” status, meaning the disease does not circulate here. But, what’s actually been detected is the genetic signature of polio vaccine, rather than the wild-type disease itself. Nevertheless, this is concerning because we don’t use live polio vaccines here any more, so this must have come in from abroad; and the sustained presence of the agent over many months, which is what’s been found, suggests that it’s found a toe-hold in the community, arguing that not enough people have been vaccinated to stop polio spreading. And if the spreading, weakened vaccine strain mutates into a nastier form, which can happen, we could have a problem. Virologist Wendy Barclay…

Wendy - We've had this announcement from the UK health security agency that some poliovirus has been picked up in sewage samples. So we do this routine surveillance where we look to see what viruses are out there in the water, and it can indicate what viruses might be circulating in a community in a certain place. Whereas we normally pick up very few of these polio viruses. There've now been some reports all the way through from February, till May. There is some vaccine derived polio virus in the sewage samples that have been collected in North and East London. This has caused some alarm because there's more of it than usual and over a longer period than usual, which suggests that there could well be some level of circulation in the community there.

Chris - If it's a vaccine, why are we bothered?

Wendy - The fact that it's a vaccine is interesting in several ways. First of all, we don't use the live oral vaccine against polio virus at all in the UK. We use what's called the inactivated polio virus vaccine. So that tells us that this virus which is circulating has been introduced from somewhere outside of the UK. The fact that it's circulating again is not unheard of, but the fact that it's circulating suggests that actually there are a group of people in whom it's circulating who are not immune to polio, and that's a bad way to be. We don't want there to be groups of people in the UK who aren't immune to polio.

Chris - So we've got really two headaches here in the sense that we've got admittedly vaccine derived polio virus circulating, so it's not just a one off pickup from one person shedding it. The fact that it's been there for months shows that it must be circulating among a group of people. And this shows that there's enough people who are not immune to polio in the immediate area this is happening, that it is clearly transmitting among those people.

Wendy - Yes, that's right. And then the third thing to worry about is that although the live attenuated polio virus vaccine that we have used orally in the UK in the past and is still used in a few places in the world is a good vaccine, it is attenuated as with all viruses, it can mutate. And if it reverts to being fully virulent, what that means is that it's a vaccine derived virus, but it's no longer necessarily completely attenuated and could cause serious illness.

Chris - So what will the public health practitioners who have sounded the alarm now be doing?

Wendy - So what public health agencies will be encouraging people to do is to come forward and get a polio vaccine. They will be offered the inactivated polio virus vaccine, which is widely available in the UK, and that will protect them against any serious consequences of picking up this particular vaccine derived polio virus.

The tympanometer, minus the smartphone, can be assembled for a material cost of around $28. The hardware design and software code are open-source and freely available.

17:48 - Smartphone tympanometer identifies ear issues

In resource-poor settings, diagnosing ear problems is challenging. A smartphone & some cheap parts can help...

Smartphone tympanometer identifies ear issues
Justin Chan, University of Washington

Being able to hear properly is critical for the development of language and education. But in resource poor settings, like Third World countries, it can be hard to achieve an accurate diagnosis of an underlying ear disorder that may be hampering hearing and therefore damaging a person’s potential. That’s because the equipment needed is often preclusively expensive. But now scientists at the University of Washington have come up with a way to use a smart phone to study the performance of the middle ear. This is called “tympanometry” and Julia Ravey heard from Justin Chan how it works…

Justin - Ear infections affect the mobility of the ear drum because fluid that's infected or not infected, can accumulate behind the eardrum and make it stiff. And tympanometry is really one of the key tests that are used to measure middle ear function but these devices are quite expensive. They're two to five thousand uUS dollars, and this makes them inaccessible, especially in low to middle income countries. These hospitals have to rely on a very small number of tympanometry devices. So patients are coming from like nine hours drive away just for hearing screenings or other types of checkups like this.

Julia - And how does a tympanometer work?

Justin - I can present that in the context of what we have here. So what we built was a low cost tympanometry device. This is smartphone-based with parts that are only about 20 or 30 US dollars, and the parts can be purchased anywhere. So the hardware and the software for this are open source for anyone to replicate. What I'm showing here is the attachment; a syringe. So this is a medical syringe. And the idea here is that we have a motor that moves the plunger very small amounts; at sub millimetre precision. And this connects through a series of tubes that ends up in the ear. So the plunger actually ends up moving the eardrum very small and precise amounts. And at the same time, we are sending a sound via the same tubing into the eardrum and we are measuring the sound that comes back. What happens is that the recording of the sound changes as you flex the eardrum and this recording it's called a tympanogram. That's used for making clinical decisions, especially related to diagnosing ear disorders.

Julia - And so that device - you've just shown me it there - it's sort of like a box that sits on the back of your smartphone and it's all very compact and portable. There's a big long tube with almost like an earbud on the end that goes into the eardrum. And that's taking a measurement of how stiff or how flexible the eardrum is. So then do you get a readout of that on your smartphone?

Justin - Exactly. You get a real time reading on a smartphone like this. This graph here just looks like a little mountain. So the height of the mountain and the width of the mountain are key metrics that are used to determine how flexible the eardrum is. So for example, an eardrum which is too flexible will have a much higher peak one than one that's not flexible enough, with maybe a lower peak. And if you have an ear infection where your eardrum is stiff, it will actually just show up as flat; the eardrum will not move at all, even if you are adding or decreasing pressure.

Julia - And have you tested this out and compared it to the original machine that will be used in this situation to see how they compare?

Justin - Yes, we conducted clinical testing on 50 paediatric ears, and this was done in parallel with a clinical-grade tympanometry device. And we showed in our study that there was good agreement between both devices of about 86%. So this is promising and we think that for future studies, testing this out in the field will be useful to evaluate the durability of the device.

Julia - And once you get the read out from the device - say you've built it and you've done a read out - and it's saying that your eardrum doesn't respond as it should be doing so potentially you have an infection. Then what do people do with that information?

Justin - This information is typically used by a clinician in combination with other tests to guide middle ear disorder diagnosis. So this is typically just one part of a battery of tests to diagnose the function for the middle ear. This can diagnose quite a large range of disorders, so the exact follow up procedure will vary from patient to patient.

A man's nose.

People Befriend People Smelling Like They Do
Noam Sobel, Weizmann Institute

“We sometimes encounter people, even perfect strangers, who begin to interest us at first sight, somehow suddenly, all at once, before a word has been spoken.” - the words of Fyodor Dostoevsky in his novel “Crime and Punishment.” It might have been written in 1866, but it’s still absolutely true today: there are people with whom we feel an instant bond when we meet them. But rather than it being down just - as Dostoevsky suggested - to what they look like, what they smell like might be a hidden part of the formula. A new study has shown that people with the same body odour profiles are much more likely to “click” instantly and become friends. It was an idea hatched by Inbal Ravreby, at the Weizmann Institute in Israel. She works with Noam Sobel, who joined Chris to talk about the work, but from a slightly unusual venue, because Israel’s got strikes going on, just like we have…

Noam - I'm actually hiding behind some building in a pool with my children running around here somewhere because there's a teacher's strike in Israel today. So life has been turned upside down a bit.

Chris - <Laugh> So we've got trains on strike. You've got teachers on strike, but science prevails. We're gonna try and converse all the same and you're hiding behind this cafe. I hope they don't mind. Tell us about this study. The people that you're there at the pool with, do they smell like you?

Noam - I think the chlorine is probably knocking. Everybody's smell out here, but this study is about the fact that people are smelling each other and they're probably making decisions based on that. And so this particular study is decisions of the type of who you would like to befriend or become friends with. Basically it built on two observations. So one is we know for a long time that people are constantly sniffing and smelling themselves. If you just observe people, whether I do that now at the pool or you at, at your radio station or wherever people are constantly smelling themselves. Of course, if you wanna take this to the extreme, in our lab, we call this the "Lev Effect" named after German football coach, Joachim Low - or "lef" depends how you wanna pronounce it - and to those of you who have a spare minute - and this is not for the faint of heart - you can go into YouTube and perform the search "Joachim Low sniff", and you will be amazed! But that aside, we all do this. So, people are constantly sniffing themselves. We also sniff strangers, but we tend to do this in a covert manner. For example, a study from our group demonstrated that often after we shake hands with individuals, the hand that shook then comes to our nose. And the question is, what does this serve? Why do we do this? And what Inbal, the lead author, hypothesised is that we're comparing - at some subconscious level - we're comparing our own odour to other people's odour. And if the odors are the same, then that promotes social interaction. That's good for connecting. So we become friends with people who look like us, with people who have similar values to ours, even with people who have similar patterns of brain activity to ours. So similarity promotes friendship. Maybe similarity promotes friendship in body odour as well!

Chris - So how did you test that then?

Noam - Inbal concentrated on a very particular type of social setting? What she refers to as "click friends". Now, this is something we're all really familiar with from our life. Do you have any person you ever met and, you know, the minute you met, you clicked? Everybody's familiar with this phenomenon, but how did that happen? What was it there that made you click? And Inbal hypothesised that this would be chemistry. So she recruited from around Israel pairs of click friends. And once she identified a cohort of both male and female click friends, she then sampled their body odours.

Chris - But how do you actually smell that, and work out what the smells are that are on the odour profile?

Noam - Right then Inbal carried out two types of experiments. In one, she used the device we call an electronic nose. Now this is a bit deceiving because it's not really a nose, but it's a set of chemical sensors that are supposed to act like a nose. And so she smelled these pairs of body odours with an electronic nose, and then she smelled also just random pairs of people. And she asked whether the electronic nose finds the body odour of click friends to be more similar to each other than just random people. And the answer was a resounding yes, click friends smell more similar than just random pairs of individuals.

Chris - What about if you go the next step and say, "I'm now gonna ask a human to do it."

Noam - And so Inbal did exactly that, and she had cohorts of smellers smell these body odours and rate their similarity. And once again, consistent with the e-nose results, she found that smellers find that click friends - these pairs of people who are friends - smell more similar to each other than just random pairs of people.

Chris - Have you gone a step further, which is to make someone smell different?

Noam - Ah, have you been spying?

Chris - Well, maybe. I've been hanging around your swimming pool! Because, if you could take someone who, you know shouldn't be friends and subvert the smell system by making them smell better, could you do that? Or have you tried that?

Noam - So you, you know, so that's a superb question and, you know, in science jargon, what that means, if a scientist tells you that your question is superb, that means that's just what they're working on now. So yes, we're doing exactly that right now. We found a way to engineer people's body odour. And so we have now formed groups of people that we've engineered to have body odour X and other groups of people that we've engineered to have body odour Y. And we're seeing if the Xs get along together with themselves better than they get along with the Ys!

Chris - Does it work?

Noam - I don't know yet. We're also doing part of it while conducting functional magnetic resonance imaging, or brain imaging. So in other words, we're measuring the brain response while all this is happening, because we also want to identify the mechanism that's underlying all this. But we're doing exactly what you suggested we do. Namely, see if we can engineer a social interaction by engineering body odour.

Chris - Do we sort of do that as a race anyway, because when I get out the shower, I reach for the deodorant tin or I reach for the aftershave or whatever. We all do it. We all distort our natural smell profile a bit don't we?

Noam - I, you know, that's, that's a good question that, that actually we haven't yet really systematically addressed. We don't know. I'll just say one word on that. There's an interesting set of studies from about 20 years ago or 15 years ago. And what they found is that people actually select perfumes that are in a way of function of their own genetic makeup. So even your selection of perfumes is not a random act. It's something that reflects your body chemistry in some way!

Virus cells

30:49 - What is an emerging infection?

Knowing the enemy is the first step to overcoming it...

What is an emerging infection?
Jonathan Ball, University of Nottingham

As if anyone needed reminding, for the last 2 years the world has been in thrall to the Covid-19 pandemic. Before that, a huge outbreak of Zika virus that was linked to birth defects hit Central and South America and then rapidly spread to other countries. A couple of years before that happened, the world saw the first cases of Ebola outside of Africa and the largest recorded outbreak of the disease within the continent itself. Shortly before that, swine flu swept the globe, hot on the heels of the original SARS virus that emerged from China in late 2002 and spread internationally...

Jonathan - An emerging infection, Chris, is an infection that has suddenly appeared within a population or sometimes we can think of emerging infections as something that has been infecting humans for quite some time, but it suddenly gets introduced into a new geographical range, for example. So generally we think of them as new kids on the block as it were.

Chris - And where do most of them come from? When we've got a new entity, it didn't just pop into existence. It must have come from somewhere. So where do most of them appear from?

Jonathan - It's a great question. If we think about the novel infections, the unknown infections, for example, things like SARS Coronavirus, MERS coronavirus, and indeed the recent SARS two. These are viruses which have been circulating in animals, we think in bats, and they may well find their way into what we call an intermediate species. This is a species that acts as a kind of gateway into humans. So the virus jumps from the bats potentially into this intermediate species and then into humans. And if the virus is able to infect and replicate and then transmit in humans, that virus can then start to explore humans as a new host. Now, sometimes the virus needs to gain some mutations to be able to do that, but, sometimes the virus is pretty much ready to go and we think that's certainly the case for the related SARS viruses. And so that's one example of a virus popping out of an animal host into humans. And we can think of HIV as being very similar, also Ebola virus. But if we think about things like a Zika, for example, what we see there is a virus that has expanded its range. So it's gone to new geographical locations. And so what's happened is the virus has been circulating for a very long time in Africa, also in the equatorial ranges within Asia. And then something's happened that has allowed that virus to then transmit across the Pacific ocean and then find its way to Central and South American shores. And so it's these sorts of activities, also things like climate change, etc., that allow the viruses to expand their geographical range in their hosts. As the climate, the globe, warms, so the insects that carry many of these infections, infections like Chikungunya virus, Dengue virus, these are all viruses that rely on insects to spread them. And as the global temperatures warm, the insect ranges increase and therefore you get the viruses introduced into populations.

Chris - So it sounds to me really that you're saying there are possibly three things going on: one is that we, in some way, bring ourselves into contact with where a virus naturally is, or we move the virus to somewhere else or, something else changes which encourages an animal or a thing that has the virus to move. But, either way, it ends up with the virus, or where it is, rubbing up against us. And that gives it the chance to jump.

Jonathan - Yeah, absolutely. If you think that human populations have increased significantly also because of that, we then need more resources. We've started to encroach on wildlife habitats. What that does is bring us into close contact with animals that we wouldn't have normally come into contact with. And, of course not just us, but also the animals that we've domesticated and tamed, for example, livestock. So it's this encroachment upon habitats, but also the globalization. So the fact that we can travel huge distances, and the fact that we ship goods over huge distances, has given not only the viruses, but sometimes the insects that the viruses rely on, the opportunity to explore new domains and new realms and new human populations.

Chris - Yes, I did read the headline when the World Cup came to South America, and they were saying "fever pitch" because of the worry about people moving on mass by the million to go and watch World Cup games. But I suppose it's that mass movement that has the potential just very briefly to amplify these sorts of outbreaks.

Jonathan - It is. You know, wherever you've got people moving over large distances very rapidly, then you can see the transfer of infectious diseases following those mass migrations. So we live in a different world than we did several decades ago. And that's why we're seeing far more of these emerging infections.

Monkeypox graphic

36:56 - Monkeypox in the population

Why the sudden uptick in cases of this smallpox relative?

Monkeypox in the population
Michael Head, University of Southampton

In mid-May, alarm bells began to ring among public health practitioners in a number of countries when they noticed a sudden spike in cases of the rare disease monkeypox. Caused by a close relative of the smallpox virus, it’s normally found only in a handful of African countries where it’s naturally an infection of small mammals like rats and squirrels. In this respect, monkeypox is a misnomer: monkeys are only an accidental victim, like we occasionally are. People who catch the disease, usually after contact with an infected animal, often present with a high fever, swollen glands, muscle aches and weakness, and a pustular blistering rash. So why are lots of cases abruptly cropping up among men in western countries with no travel history to parts of the world where the disease is endemic? What’s changed? So far 2000 cases have been found across 40 countries, and one person has died. Michael Head is a global health researcher at the University of Southampton..

Michael - So, this Monkeypox outbreak is not like any Monkeypox outbreak we've seen before. Usually, they've been quite small in number and have been restricted to the parts of Sub-Saharan Africa that you mentioned, particularly Nigeria and Ghana, or sometimes the Democratic Republic of Congo. Here, the index case, that first case of this outbreak, will almost certainly have had a travel history with those parts of the world. We may or may not have detected the index case here and maybe it went under the radar, but it's almost certain that it will have come from that part of the world and that it will have brought the Monkeypox infection with them. With these cases that have been reported over the last few weeks, they are almost all, if not actually all, linked to these sexual networks amongst men who have sex with men and the transmission has taken place within those networks. We know that Monkeypox spreads predominantly via skin to skin contact. Well, it's very, very close contact. So, it's presumably the case that the rashes and the blisters that we see typically present with Monkeypox, as they appear on the skin, that will have been the mode of transmission from one person to another. So far, the wider community has not been impacted. So it's very, very different to, for example, Covid, which of course is a respiratory infection where everyone is at risk around an infectious person. But with Monkeypox, you do need that close contact. And within these sexual networks, there has been that close contact enough to transmit it initially, and then to sustain transmission across a few countries.

Julia - So we're seeing these cases of Monkeypox increasing, but we've had imported cases in the past before. So why is it now that these cases are taking hold?

Michael - So there will be a combination of several different factors that are combining here to create an outbreak that appears to be sustaining for at least a little while. One of that is population mixing as a result of restrictions being lifted from the pandemic that we've seen over the last two years. Populations are starting to mix in greater numbers. And if you introduce one infection into that community, you then provide opportunities to transmit further. As we have seen within these sexual networks, specifically with Monkeypox, we know that the smallpox vaccine does provide some level of protection against Monkeypox. Now, the smallpox vaccine was used routinely in decades previous across the globe, but it's not been used routinely for many years now. So it might well be that we're seeing a reduction in population levels of immunity against smallpox, which is therefore translating into reduced immunity to Monkeypox as well. And if there are, again, encounters between humans and animals to create that initial infection, then the population mixing might mean further cases beyond the index case. So there's a few factors like that that are combining to create outbreaks. Like we're seeing here with Monkeypox.

Julia - Now we've been seeing this increased transmission, what is being done to contain it?

Michael - So the key aspect of this will be the contact tracing by the public health teams to find contacts of cases and people who might be at high risk of infection. And that is a little bit of a tricky job here, because we do want to highlight the problem to those high risk populations, who are these gay sexual networks, but also we don't wish to stigmatize them. So it does pose a little bit of a problem for the public health teams. And of course the media and people who have to report on it, but we do want people to come forward. The sexual health teams who are dealing with this are extremely expert at doing so. So, actually, within this particular population, with a population that's probably used to being contacted about possible outbreaks, and certainly a public health level of expertise is used to addressing these problems as well. So that contact tracing will be crucial to reduce the number of new cases, to highlight the transmission, and where the risk areas are, and ultimately to slow down the outbreak and eventually bring it to a close.

Julia - And now that we're seeing these cases here, do we think that Monkeypox could become endemic in other countries like the UK? So if it got into these small mammals that normally carry the disease, could it then just become a disease that's in the background here in the UK?

Michael - That is a concern, yes. We certainly don't know if that will happen, or even if it's likely to happen. But it's something that the public health teams, the global health teams, will need to keep a very close eye on, to see if it does become endemic in our rodent populations, for example, or in any other small animals. It could happen. It may or may not happen. There's a lot we don't know about Monkeypox because there's been so few cases, generally speaking, across the world, and certainly few cases in Europe or North America, or other westernised parts of the world. So, again, a bit like Covid, it's a crash course in learning about an infectious disease as the outbreak happens. So only time will tell on that.

a photo of migrating birds

43:26 - Biggest Ever Bird Flu Outbreak

Some diseases can experience a resurgence after a long time in the background...

Biggest Ever Bird Flu Outbreak
Ian Brown, Animal and Plant Health Agency

Not all emerging infections are brand new kids on the biological block: some are old diseases in a new form. Flu is a good example. This is originally an infection of aquatic birds that has jumped into humans more recently, giving us human flu, but continues to circulate in its bird hosts as “bird flu” from where it occasionally makes new jumps into humans, spawning flu pandemics. And the more bird flu cases there are, the greater the risk of this happening. In fact, in recent months, many countries have seen massive bird flu activity. And much of that is down to us. Ian Brown monitors this at the Animal and Plant Health Agency...

Ian - Currently we're hopefully about to exit the largest ever outbreak the UK has had. And this is a problem that's not just in the UK, it's across Europe, across Central Asia, down in Africa, and into North America. So what's happening here is this bird flu strain has been evolving in wild birds. And of course, some of those wild birds move substantial distances on their normal migration, taking the virus with them and where they take that virus it will occasionally then spill over into poultry, chickens, turkeys, ducks, and this virus has a very highly lethality and it's happening now because this virus has improved its fitness. So a bit like COVID has done with new variants emerging, it's exactly the same. It's happened with birth flu. New variants have suddenly emerged over a period of time. And now we've got a particularly fit strain.

Chris - Given that flu has been around for thousands to millions of years. Why are we seeing this intensifying? Something must have changed which is driving this harder.

Ian - Yeah. That reflects a number of different systems. In some areas we rear and produce birds in a different way to how we used to. There's greater connectivity, there's greater density. So that means when a disease enters those birds, it's more easily able to spread. We also produce birds in an environment where connectivity with wild birds is relatively free and easy. So the virus can move between poultry and wild birds in both directions. Then you've got the dimension of climatic factors: urbanisation, wild birds will go through their annual cycle, which involves, for some species, migrating. And of course that is a key mechanism for moving this virus.

Chris - The parallels, as you highlight, with COVID are quite striking aren't they? So what you're seeing at the moment is a variant of the virus that's a bit like Omicron. It's evolved to become really easy to spread, but then you've got the human factor that also hands the trump card to the virus, because we've got loads and loads of animals all packed together in quite high density intensive farming. And then we've got the vector, which is like us on aeroplanes with COVID going on. Those wild birds from one henhouse to the next.

Ian - Behaviour is obviously a critical part. As you say, once the virus is in poultry of course, if we don't take steps to limit it's spread from one farm to another or one premise to another, then of course the virus is very able and efficient at doing that. And in some areas they do have this problem of stopping lateral spread as we say, spread between different sites and different farms.

Chris - What's the risk to humans? Is there one?

Ian - This virus in some circumstances can rarely jump to humans. We had a single case in the UK this winter which was through very close contact with birds, very mild clinical disease, and was only picked up through active surveillance. In some situations, people can get exposure to a very high dose and they can suffer more severe disease. That is a very rare event. And this virus is a bird virus. It wants to be in a bird. It does not want to be in a human.

Chris - But as we saw with Covid, one theory is that, this being a bat virus, it took people getting up close to bats and putting pressure on the virus, as it were, to jump the species barrier. It got into a person, once it's into a person, it can humanise. Is there not a risk that it could turn from something which is not very good at infecting humans into something that's much better at infecting humans. And then we could get an outbreak in humans of a new kind of flu?

Ian - Yeah. And that is a risk. And of course, that is the theory for the emergence of pandemic flu. Generally, when the virus is able to cross, it's because there's no hygiene measures being taken by those individuals. They're exposed to the birds and their secretions that are full of virus. So they get exposed to high amounts of virus. The second thing of course is managing the infection when they are in birds: taking prompt action to isolate those birds and deal with the outbreak effectively. And of course, that's what we aim to do internationally. So it's about prevention of exposure. It's about monitoring those people, but it's about taking action to control the infection effectively in birth. Now, if that is done, you can mitigate that risk. But where that isn't done, the virus has the opportunity to jump into a human and then maybe successfully make that transmission from one human to another.

Chris - Climate change is predicted to really shrink the amount of livable land area that we have available to us. It probably goes for animals too, doesn't it? So are we expecting to see more of this kind of thing in future, as more people and more animals converge on less and less resources; water, land, where they can live and therefore the opportunities for jumps like with bird flu, but other things as well.

Ian - Unfortunately, yes. It is a numbers game, isn't it? The more possibility for connectivity between these different populations, the more possibility pathogens can jump. Prior to 1997, the particular strain of bird flu we have now, causing these international episodes, was a very rare pathogen. Now, over the last 25 years, there have been changes in how we rear birds. There have been changes in how we rear poultry and how they connect with wild birds. All of those changes, influenced by different drivers, including climate change, where they bring that connectivity closer together, they increase the risk of a virus going from one population that it normally is present in into another new population that it doesn't normally reside in. And that has contributed undoubtedly to the increased scale of the problem with birth flu and all of that is good for a virus to spread. It's a perfect breeding ground.

Covid19 virus

50:25 - Learning lessons from previous pandemics

What shape should measures take to prevent future pandemics?

Learning lessons from previous pandemics
Vincent Racaniello, Columbia University

Of course, the most relevant example of an emerging viral infection at the moment is Covid-19, which has cost trillions. This means it’s also served as a wake-up call and also as a learning opportunity to put in place better safeguards to try to reduce the risks of this happening again. So what shape should those measures take? With us is virologist Vincent Racaniello, from Columbia University...

Vincent - In my view, there's one main takeaway and that is we were caught totally unprepared and we need to do better surveillance to know what viruses are out there, poised to be the next pandemic. We just can't afford to be surprised like we were with Covid. Covid Itself tells us that we can do this surveillance; we are surveilling humans, we are surveilling sewage, we are surveilling all sorts of animals so we can know exactly when and where the new variants are. We do a great job doing surveillance for influenza virus as you just heard. We can do that for other viruses, but we barely do it. Take the polio detection in sewage in the UK - we don't even look in sewers in the US for polio virus. And so the threat is out there in animals. It's mainly in mammals because the viruses of mammals are the ones most likely to infect us. The most numerous mammals are bats and rodents, and our surveillance of them is minimal. We need to know what's out there. First of all, we need to know all the viruses that are in those animals in bats and in rodents. We need to know where they are. And then we need to do a surveillance program akin to the ones we do for influenza viruses and COVID. And we need to know what's out there. We need to know at the interface of these animals and people what viruses are circulating. And we have to look in people as well. We have to have some kind of surveillance programme where we look at, say, people who are at the interface with bats in the countryside, people who are at the interface with rodents, and we need to know what travel is doing to these viruses. We have nothing of this sort. And that's really the lesson I hope we learned from the COVID pandemic.

Julia - And we're seeing these increased numbers of cases of monkeypox now. So if we were more widely surveying different viruses and different animals, do you think these cases we're seeing now could have been prevented?

Vincent - It depends on how extensive the surveillance is. Right at the moment, our surveillance of monkeypox is really nonexistent. And we're only looking now because we have cases, but we don't even know which rodents are harbouring this. There's very little wildlife sampling for monkeypox and we need to do that. There's no routine sampling at travel locations. So if we could do that, we would've known, "Oh, look, suddenly there's circulation of monkeypox virus and maybe we should look out for it before we have the first cases." So, the answer is, if it's done properly then yes, we could have anticipated this particular outbreak.

Julia - And this goes beyond just surveying these different viruses. There's also problems accessing data in different countries. So are the ways that we can solve some of the political problems that also contribute to new viral infections emerging?

Vincent - Well, that's the big problem, right? Because politics supplies the money to do all of this research. And so the data that we generate has to be shared by everyone. It would help to have laboratories in many countries generating this data instead of sending samples, say, from Central Africa to the UK and the US. Make laboratories in those locations. Immediately put the data on servers so that everyone could access it. The money to do this is the problem, right? This is going to cost a lot of money and inevitably politicians will say, well, what really is the risk of the next pandemic? And do I have to spend 10 billion a year to find that out? I don't know how to get around the political issues because I'm a scientist and that's all I know.

Julia - And as a final question, a lot of these infections arise in countries with less resource. So is there a way that we can equip these countries to be better at surveillance?

Vincent - Yes, I do think so. The lesson comes from the Ebola outbreak in West Africa in 2015, where many individuals set up the technology locally in order to do viral genome sequences, rather than shipping out the samples elsewhere, they set up laboratories, they taught local individuals how to do the work, and they generated the data and they made the local people able to do it. That's what we need. We need to bring the technology elsewhere. We don't want to parachute in and out. We want to bring the technology to them. So I think it can be done. And that outbreak showed that it could be done.

Shipping containers stacked up

QotW: How do container scanners work?

Julia - An interesting question. If your car was transported overseas, then it would’ve been done through a shipping cargo scanner at the port. So how do those scanners work? Here with us is Roger Worrall from the security company Westminster Group PLC who has a few points to help us understand how these scanners work.

Roger - The scanners used to scan the contents of cargo containers are X-ray scanners, meaning we can compare them to the scanners used in airports. Your hand baggage is sent through an X-Ray baggage scanner which have two x-ray generators, typically 180 kV each. Your hand luggage can contain your mobile phone, camera, laptop, iPad, Kindle which all go through the scanner unaffected. Your hold luggage goes through a larger size physical size X-Ray scanner or a CT scanner, again there is no effect to electronic devices.

Julia - X-ray scanners work by sending out X-rays from a generator, towards the object inside. These rays are then absorbed at different rates depending on the materials within the object. A detector on the other side then picks up the X-rays that aren’t absorbed and displays the image based on the radiation that passed through.

Roger - Sea freight containers are X-Ray scanned using a 6 Mev or a 7.5 Mev x-ray generator, that’s over 33,000 times more volts than the airport hand luggage scanners mentioned earlier. And yet in these cargo containers, electronic devices should still receive no damage.

Julia - That’s because the increase in power doesn’t affect the wavelength of an X-ray. X-rays have a very short wavelength, which is what allows them to travel between molecules. 

Roger - When scanning a whole vehicle, the driver first leaves the vehicle and the scanning system runs on rails and passes over the truck cab and container. Mobile Scanners extend an arm out that contains the x-ray receivers, the driver then drives the arm over cars, trucks and containers to see what’s inside.

Julia - So Alaster, it seems that the scanner may not be the cause of the electrical faults in the cars. X-rays aren’t designed to affect electronic equipment. We do hope you’re able to find the answers for how this happened to your car in the insurance investigation. Next week, we’re figuring out this function of fridges, from listener Josie

Josie - Why can't I immediately open my fridge door after closing it? It feels like air pressure is keeping it closed. Is this the case?


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