How It All Started (Rebroadcast)

editor Jason Gale has more. The story of bats and viruses can be traced to an Australian veitnarian, Dr Hume Field, the son of a policeman. Hume grew up in various parts of the northeastern state of Queensland were developed a fast a nation for Australia's native fauna. I've always had an interest in animals, and I guess growing up as a kid, I can remember my parents saying our human lives animals. He's going to be a vet And this was really a bit of a throwaway line because nobody

in our family had ever been to university. Led Alane to a five year Mrginry course, but nonetheless, the sort of seed took hold. I guess at least with me. When I caught up with him, he was in his home office in a leafy coastal area southeast of Brisbane. You can hear chattering wildlife and vocal pets, as well

as drought breaking rain. Him graduated from the University of Queensland in six He worked for a couple of years in a small animal practice, but his interest in wildlife led him to pursue further study in the evenings, first in environmental science than a doctorate in the mid nine It allowed him to combine his love of native animals with emerging diseases, a time when the state's agricultural authorities were trying to figure out the source of a deadly

horse disease. He was a virus that infected twenty race horses stable in the Brisbane suburb of hend It's thought to have started when a mare called Drama Series was brought to the stables after she had been grazing in a field at Cannon Hill, on the other side of the Brisbane River. Drama Series died two days later, and subsequently all of the other horses fell ill. Thirteen of them died. What was especially alarming about this disease was

that it crossed the species barrier. A trainer and another person tending to the horses became ill with a flu like illness within days of Drama series death. The stable hand recovered, but the trainer died of respiratory and kidney failure. The virus was eventually isolated and named Hendra virus after the suburb where it was found. Hume was asked to help determine how Drama Series might have caught the virus. He went searching the paddock where she had been grazing

and resumably had become infected. He caught rodents, possums, feral cats and reptiles and tested them for hendra virus. When the results came back negative, he went searching for clues. By the people rescuing vulnerable wildlife Here in Australia, they're sometimes referred to as wildlife carrots. So we subsequently broadened our search and started using wildlife cares as I as a conduit if you like, to be able to collect samples from sick and injured animals that were in their care.

And it was in that process so again quite serendipulous, that we actually sample. We were sampling kangaroos, we were sampling parsons, we were sampling the usual things, darks, the whole range of things that would come into wildlife cares. And there were flying foxes on your samples, some flying foxes. This was over a period of months, and lo and behold we found antibodies to hendra virus and some flying foxes.

So we looked at some more flying foxes, and then we looked at some flying foxes in captive populace and the zoos, etcetera. And that's how we identified flying foxes as being at that stage are possible rest of while, then we went on to do further studies eventually detected an isolated virus etcetera, etcetera. And so now flying foxes or at least a couple of species of flying foxes in Australia are recognized as the primary reservoir hosts of

hendra virus. Flying foxes aren't actually foxes. There are large fruit eating bat with a kind of fox like face and expression. They weigh up to a couple of pounds and their wings can span more than three ft. The finding of hendrovirus and bats was important, not just because It helped identify the pathway by which horses and people were being infected. It also made scientists alert to other

viruses bats could potentially carry. About a year after humid the discovery of hender virus and flying foxes, another opportunity to explore the ecology of viruses and bats presented itself, this time in Malaysia, where pigs and pig farmers were getting sick. By mid more than two hundred and sixty five people had fallen ill with encephalitis or inflammation of the brain. Of those cases were fatal. There were also eleven cases of either encephalitis or respiratory illness, including one death.

Neighboring Singapore, scientists found the viral source. It was named neiper virus, which had turned out was from the same family as hendra virus. Hume was asked to help investigate the source. I wanted someone who was who might be able to guide and work with him to find out the natural reserva. So none of we knew about hander

and bats. Then we immediately focused, not exclusively, but we certainly focused on flying foxes in Malasia, and it wasn't soon long before we found evidence of NIPA virus in species of fine fox there, just as Hendra virus did. The discovery of NIPA underscored their risks that emerge at the interface of wildlife, farm, animals and humans. Professor Trevor Drew is the director of the Australian Animal Health Laboratory at Geelong, just outside of Melbourne. It's carried out key

research on both Hendra and niper viruses. According to Trevor, the emergence of Hendra and then Nipper identified the ways in which batborn viruses can spill over it and infect

other species. And Nipper virus was a disease also of fruit bats in Malaysia initially, and that virus got into pigs because the they were starting to put pig farms into more forested areas, and the feces from the bats got into the pig styes and was thought to have infected the pigs that way, and it killed hundreds of pigs, if not thousands of pigs. NIPA isn't just confined to Malaysia over the past decade. It's caused outbreaks in India

and Bangladesh that have killed dozens of people. We also now as also know from incidents in Bangladesh of outbreaks of NIPA virus that you don't need the pick that the that the bat can actually also infect humans directly via drinking out of vessels of palm sap that are put onto the tree to to harvest the palm sap, and people drink this palm sap, but so does the bat and they will come down and the saliva from the bat can contaminate the palm sap and infect the

human directly. So we know that that that is one incident, but certainly in Malaysia now they're very very careful not to have pig farms near bat roosts. And even more dramatic outbreak occurred just a few years later. Severe acute respiratory syndrome or SARS, emerged in southern China in two thousand and two. It's a deadly a cousin of COVID nineteen that quickly spread across the world. Hum Field was

asked to help investigate its source. And because of our experience with bats and hand virus and needle virus and growing awareness that there seemed to be something special about bats and these spillovera viruses, then we hypothesize that bats may play a role in the the origins of stars,

and so we went down that track. It's interesting to reflect on the significance of the discovery of species of bats and flying foxes as the natural reservoir of hendra virus because really that finding, I think has potentially colored the identification of bats, or you know, sort of underlying the identification of various species of bats being a socialate with this suite of other emerging diseases that we've seen

over time. If we have the group that Hume just referred to also includes a bowl of viruses and list of virus which causes rabies, as well as a number of coronaviruses, including stars and most likely the one responsible for the COVID nineteen pandemic. So what is it about bats that makes them such great virus vectors. That's a quite unique if you think about it in terms of

them being a mammal that can fly. So so ba's are mammals, they produce milk cyclely young they but they have got this amazing evolutionary adaptation or ability to be able to fly so highly mobile. They also typically live in large populations colonies roost, whether it's the big fruit bats or flying fox is whether it's small microbats in caves, and typically these groups have mixed species as well. Um

they're relatively long lived animals as as a taxa. You know, flying fox are certainly recorded, I think in captivity to live well into twenties. Certainly wouldn't live that long in nature, but certainly you know, they live for years. So all of these factors are very attractive for mammalian virus survival

and dissemination, if you like. According to Hume, bats have evolved and adapted to coexist with the viruses that infect them, and so the thinking was that, well, you know, these are just viruses of bats, and the bats are used to them because they've evolved with them, and that's why the bats don't get sick with these viruses. But if they spill into other naive, immunologically naive species, then they

have a dramatic, simularly dramatic and often fatal infection. But more recently people have dug a bit further to try to understand if there isn't doing something else going on with bats, and it seems that there isn't. Hume now works as a science and policy advisor with the Eco Health Alliance. It's a New York based NGO that works to protect wildlife and public health from the emergence of disease.

Spill over events are becoming more risky. Bats, as we heard, are coming into closer contact with farm animals, but they're also coming into closer contact with humans. A key reason for that is that bats are losing their habitat. Critically, they're losing their natural food source. What you're hearing is the sound of gray headed flying foxes roosting. It's dusk and I'm sitting on a grassy bank of the Times River in the center of Adelaide, the capital of South Australia.

I'm literally a stone's throw from the University of Adelaide, my alma mart behind me, and the Adelaide Zoo on the other side of the river. This is a popular place for the twenty thousand bats hanging upside down from the eucalyptus trees above me. It's a familiar place for Dr Mark Ship, Australia's chief ventinarian, who is based in Canberra but also grew up in South Australia. Mark is

the president of the World Organization for Animal Health. He told me that bats have taken up residency in Adelaide and other urban centers, but not by choice. Yes, almost every city in Australia now has a resident roost of

flying foxes. And the fruiting and the flowering trees that these bats normally feed on have been largely removed from rural Australia and so they've been forced into urban centers and suburban park land where there is some flowering trees and some fruiting trees, but these are not the preferred diet of the flying foxes and they're putting those flying foxes under stress. We've seen a number of incidents in Australia over recent years with large scale mortalities of flying

foxes due to heat events. Here in Canberra we had a large hail storm event which killed over three hundred flying foxes. It reflects that their their in centers where they would normally not be present, and that they're under stress when they're in those centers. There's another concern with maths roosting places like this where horses are being kept

less than a mile from here. For us, that the concern is that where we have park land, we often have horses and we know that flying foxes can transmit hendra virus two horses, and that those horses and turn can transmit that virus to humans, and and that's a fatal disease of both horses and of humans. And then and then that there is the risk that the bats themselves will will transmit directly to human populations. And there are a number of coronaviruses and other viruses that bats

carry and can transmit to the human population. But there are other consequences of the loss of that habitat. While these animals can carry some pretty nasty viruses, they perform functions vital for the Australian ecosystem. They play very important roles in terms of insect control, of pollination and of seed dispersal. The role that they play in keeping down insect numbers which and and insects can transmit disease, particularly

in northern Australia, is very important. And then that the role that they play in eliminating plants as they move between plants and then dispersing seeds where they eat fruits and disperse the seeds so that those plants become established in other areas is very important and is a role that no other participant in the ecosystem can ploy. In the mammalian world, lifespan is generally proportional to body size

and metabolic rate that's defined both these rules. One bat species weighing just seven grams or a quarter of an ounce, can live for more than forty years. It's one of a number of quirks of these critters. Professor Lindfa Wang has been unlocking the secrets of bats since the nineties. He was the scientist who isolated and characterized hendra virus and identified its viralogical cousin Nika. Actually it was Lindfa who named the genus to which they both belong, hannaper virus.

Back then he was working at the Australian Animal Health Laboratory just outside of Melbourne. He now heads the Emerging Infectious Diseases Program at Singapore's Duke and Us Medical School. For the past thirteen years, he's devoted his career to studying bat biology and bat immunology, particularly its defense against viruses. He's brought a number of researchers along with him in Australia, Singapore and now China, where he was born and did

his undergrad degree in scientific circles. Lympha is sometimes known as the batman. People give me the nickname of Batman that I tried to clasp them that I actually don't started bad, but batmus. Lympha serves on the World Health Organization's Emergency Committee, advising the Director General on the current

COVID nineteen pandemic. It's a reflection of the knowledge in his twenty person lab have amassed on these animals, and we have been focusing on the question of why that's, why that's are so different, why they can carry so many laws and themselves do not get sick, and why bats lives so long. Consider their living environment and also the straps they have during fly and also the pattern and they're exposed is much much more than a non

flying mammal. It turns out that the immune system of these flying mammals is different to that of terrestrial mammals. Bat's react to infections at an earlier stage, arresting them before they cause any disease. That enables bats to avoid the damaging inflammatory immune response. Other mammals, including humans, often mount in response to virulent infections. So our current looking hypothesis is that that's have a much better defences the torrents.

Pathologists studying COVID nineteen and other pathogenic viruses have observed that when the body initially recognizes an infection, various white blood cells that consume pathogens and help heal damage tissue act as first response wonders. In some severe infections, the body's effort to heal itself maybe two robust, leading to the destruction of not just virus infected cells, but healthy tissue.

It's that inflammatory response that ends up being deadly. Bats don't suffer the same fate that can defend themselves, launch the inflammation, but they don't go over. Okay, So this is a very big area of research, and I think we human can learn Lympha says he's convinced that's offer important insights into the regulation of the immune system that may inform ways the human body can better tackle COVID

nineteen and other viral diseases. So my slogan now is that my study is basically looking from that that have so much of the features. For one thing, Limpa is intrigued that species of that that way is just seven grams has a heart that beats more than one thousand times per minute during flight. It flies for five to eight hours daily and can live for forty three years. This is all done with the same heart, with any medication, with any in the hygiene. You imagine that, right. It's incredible.

It's a little wondered that Lindfa is working with cardiologists who study the heart muscles of bats, just one of a number of medical disciplines he's recruited into his backpack. I have been able to mobilize not in passion disease, to people, genomics, people immunologists, and the cans of biologists and now cardiologists are collaboys. Be just started back. My personal dream you have enough money, is to statue a bad institute. I think that we have lots to learn

from that. That's can help us identify what viruses of pandemic potential are lurking in nature, as well as ways we might be able to mitigate their threat. They're just one example of how humans are profoundly affected by what happens in global ecosystems. To anticipate, prevent, and responded to zase threats in like COVID nineteen means taking an increasingly wide angled look at the natural world. That was Jason Gale,

and that's it for our show today. For coverage of the outbreak from one and twenty bureaus around the world, visit bloomberg dot com slash Coronavirus and if you like the show, please leave us a review and a rating on Apple Podcasts or Spotify. It's the best way to help more listeners find our global reporting. The Prognosis Daily Edition is produced by Topher Foreheads, Jordan's Gas Pure, Magnus Henrickson and me Laura Carlson. Original music by Leo Sidrin.

Our editors are Rick Shawn and Francesca Levi. Francesco Levi is Bloomberg's head of podcasts. Thanks for listening, Footable and