SARS 3: how to plan for the next pandemic
If you've heard one phrase more than any other in this programme, it’s “we don’t know”. We can make guesses, and gather evidence and hypothesise; but until someone finds the ancestor to this coronavirus, it’s going to remain a dangling question mark. That said, there are a few things scientists like Peter Daszak do know: that if we’ve had SARS 1 and SARS 2, you can bet there will be more...
Peter - I don't think ‘if’ we had a SARS-3, I think ‘when’ we'll have a SARS-3. There are hundreds of these viruses out there. People are increasingly well-connected on the planet. Every day these viruses are finding it easier to get into people and spread around the world. So we will have another one, but whether we're going to be better prepared... I really hope so, but I'm not confident that we'll learn our lesson. We haven't so far.
Phil - Could this have only happened here, in this part of the world - Southeast Asia?
Peter - Oh, well we know diseases emerge in just about all countries. We've had our own in the UK with BSE, mad cow disease, and salmonella in eggs back in the eighties. The US has had plenty of new diseases: West Nile Virus, monkeypox. It's especially common in places where there's a high wildlife diversity and lots of people doing lots of things in the environments: building new roads into forest, hunting and eating wildlife. We need to reassess our relationship with nature. First of all, we need to understand where these things come from and appreciate that when we build a road into the forest, it can be really beneficial to our economic success, but it also has a cost to it. And that cost is not just climate change or loss of acute species; it's also pandemics.
Unfortunately, while COVID may have convinced people and governments that international collaboration, surveillance and wildlife management are important, when it comes to why these outbreaks happen, and why scientists expect them to happen increasingly more often, the elephant in the room is us. Dennis Carroll...
Dennis - The biggest simple ingredient is population and population having high interaction with wildlife. The population explosion in China over the last century has meant urban settlements moving closer to wildlife domains, agricultural activities bringing human populations close to wildlife, and the disruptive effect of land use change, all creating a combustible situation where people and wildlife animals are interacting on a scale that is unprecedented.
Chris - If the driver is human population and that is going up at an increasing rate, what's the outcome? Are we going to see this even more often then?
Dennis - Well we are going to see it more often. As you said, population is increasing. We'll soon hit 10 billion, and by the end of the century, 11-12 billion people. So you can expect that, as we move into the 21st century, we're going to start seeing the consequences of that dramatic growth in human population. And the population dynamics of the world are changing dramatically. Asia, in fact, is contracting. China will have fewer people in 2050 than it did in 2000. But when we look at Sub-Saharan Africa, there you're going to see most of the growth; and in South Asia, in India specifically. So as we move into the 21st century, you can expect the risk profile of emerging diseases to follow suit with the population increase in these other geographic areas as well.
And according to Raina Plowright, as we keep shrinking the wild spaces of the world, we’re going to be gambling against the next pandemic more and more often...
Raina - At the moment, the way that we're crisscrossing the world with roads, fragmenting our ecosystems into smaller and smaller patches which then create larger edges, larger contact zones, we're certainly rolling the dice more often. We're rolling the dice thousands of times a day. But every time we have a new pathogen jump into the human population, we're taking the chance that it has just the right characteristics to be able to infect that person in the first place and then spread. And so many of these pathogens, they're probably even going unseen. For example, hospitals around the globe are full of people who have encephalitis or respiratory problems without any diagnosed aetiology. So no pathogen's actually ever isolated, there's no cause actually found. And this is probably happening all the time. These spillover events occur, someone gets sick, and we never hear anything about it.
Phil - It seems kind of inevitable though, right? I mean, what is there that we can do to stop more pandemics?
Raina - We need to look at what are the factors that really drive these events. And those factors are: having wildlife populations that are stressed, so perhaps more likely to be infected, more likely to be shedding the pathogens. And we see that with other pathogens like hendra virus in bats in Australia; when the bats are nutritionally stressed we she more viral shedding. We also will see it when there's more contact. So we need to limit human contact, especially with these novel populations; so limit the intrusions into forest, limit fragmentation, limit road development, and try to keep large, intact areas; intact areas of wilderness where animals can do their thing, they can seek their food, they can move freely, without having to come into human populations, without having to come into villages to look for food, and without having to come into contact with people because they're trying to make a living and survive.
Which means that even while we’re scrambling to survive this pandemic, we need to overcome any instinct to be short-sighted and we must start planning for the future. Peter Daszak...
Peter - I think that's partly human nature. We don't like to spend money and inconvenience ourselves for rare events, and pandemics are rare events. Even if they're once every 10 years, it's long enough between them to forget about the severity of the last one. We also have trouble justifying this to politicians who have to spend the money. You don't get voted in for saying, “we're going to spend millions of dollars to prevent a disease that we don't even know exists yet.” You get voted in for saying, “look how heroically I dealt with the ebola outbreak”, or the previous outbreak. So this is partly human nature. And I think we've got to realise we need to be smarter than that.