How did the 1918 flu pandemic start and could we have another one? | Ockham's Razor

so this year is 2018 and it's a pretty significant year because it marks the anniversary of many important events in our history so it's actually been 20 years since the release of possibly the greatest musical hit of all time the Backstreet Boys the backstreets back no okay personal preference in music but it's also an anniversary of much more significant world events things like it's been 50 years since the assassination of dr. Martin Luther King it's been a hundred years this year since the end of World War one and it's been a hundred years since the 1918 Spanish flu pandemic so there's 1918 Spanish flu pandemic the mortality estimates vary but it's largely accepted that it killed 50 million people worldwide this virus killed more people in 24 weeks than HIV killed in 24 years okay this has been described as the greatest medical Holocaust in history and I think it's really hard for us in this day and age to appreciate how severe this was but I want you to imagine that the death toll was so severe but in some countries they actually ran out of coffins so what was it about this 1918 virus that made it so bad I mean every year we have outbreaks of flu and and 2017 was it was a bad year for the flu we know that but it was nothing like 1918 so what is the difference between a seasonal flu strain and a pandemic flu strength well a flu pandemic typically happens when a new flu virus enters the human population we don't have much pre-existing immunity to it and it's easily transmissible from person to person now we still don't know really where the 1918 virus came from what we do know is that originally all flu strains actually come from wild birds from here they can actually transmit to other bird species like poultry and they can also transmit to mammals like horses pigs and of course humans for these animal viruses to jump in the human population there's kind of really two ways that it can happen so firstly it can be a direct infection so we can get infected with bird flu and you've probably heard that in the news but it can also be a bit more of a gradual process whereby a virus spreads from a bird to say a pig it then becomes much more adapted to the mammalian system and then it crosses over to us in the case of 1918 we think what happened is that the virus actually directly jumped into the human population from birds but it's pretty hard to know definitively and the reason is is because in 1918 we didn't have the advanced molecular genetics techniques that we have today in fact flu virus itself was not even discovered until the 1930s so imagine how scary it would have been in 1918 where you saw all these people dying but you didn't even know what a flu virus was there was still some people who actually still believed in the idea of miasma and that infectious disease was actually just caused by bad air so now let's jump forward go through the history a little bit and fast forward to 2009 and the 2009 swine flu pandemic now I'm sure most of you remember that if you were lucky like me you got the swine flu virus and it was pretty nasty I can tell you from personal experience so if this virus first emerged at the start of 2009 and it spread rapidly around the world so within the first year and infected between say 10 and 20 percent of the world's population this virus was actually a combination between human pig and bird flu flu strains and they kind of came together so that's why calling this swine flu is a little bit of a misnomer because the virus is much more promiscuous in its origins than just swine flu and yes viruses can be promiscuous it's about as fun as we get as virologists so go with it so 2009 you know it was a pandemic but it wasn't nearly as severe as 1918 the pandemic killed probably about 300,000 people worldwide but what this pandemic served to emphasize is that once again we have a pandemic because a virus is jumped from the animal population into the human population and the problem that we have is this phenomena is not just restricted to flu okay these jumps between viruses of different species happens throughout history so to illustrate this point I want you to cast your minds back to sort of 2002 2003 now these were much simpler times Donald Trump was busy running a reality TV show and not the United States of America maybe doing one more successfully than the other you can you can judge we had the amazing technology of those old Nokia phones if you remember those I remember being blown away and thinking that nothing could ever get better than this old Nokia phone but actually at the start of 2003 I was traveling back to Australia going by a Singapore and I remember that Singapore Airport was in absolute chaos okay they had temperature checks where at which everyone had to walk through and it would check if you had 37 degrees or higher people were wearing face masks everyone was a bit panicked and the reason was it was because of the outbreak of this new virus called SARS or severe acute respiratory syndrome now science virus first emerged in China and it rapidly spread to around 30 countries across the world now the case fatality rate of size probably wasn't that bad around 9% but it had a massive economic impact it cost the world economy about 50 billion dollars now this was not just in terms of increased medical expenses but it was also the productivity losses associated with closed schools closed businesses and a dramatic drop in tourism so at the peak of the SARS outbreak there was something like a 70% drop in international travel and about a 60% drop in hotel occupancy rates now very early in the SARS outbreak there were certain clues that this virus had jumped into the human population from animal species and this is because some of the early SARS patients were living very closely to a variety of different animals or they were frequenting things like live poultry markets so all these kind of epidemiological indicators that maybe the virus could have come from animals and actually what researchers did is they went through and they did a lot of sampling of weird and wonderful credits and what they found is actually a vice that looked exactly like the human science virus in civet cats located at some of these markets now for those of you who don't know what a civet cat looks like it looks sort of like a possum with spots I guess apologies to the civet cat enthusiasts out there five little dissipate cat but this is kind of the image of the creature you should have in your mind now it didn't really seem to fit with the all the evidence to say that these animals were the original source of the SARS virus and the reason wants is that although these civet cats were positive for the virus and there's live poultry markets wild civet cats weren't positive for the virus so it didn't seem like the virus was endemic as such to the civet cat population so what actually was discovered subsequently is that the virus was harbored by a small Chinese bat called a Chinese horseshoe bat and what thought was thought to happen was that this bat was the original reservoir of the virus and once again the sequence of the virus matched that in civet cats and in humans and it actually transmitted the virus to the human population by an intermediate host which in this case was most likely to be the poor civet cat so just like we probably shouldn't blame pigs for the 2009 swine flu pandemic we probably really shouldn't blame the civet cats for science just take home message but this idea that these viruses jumped from animal species to humans to cause pandemics and viral diseases it's so common so we have so many more examples viruses like MERS which you might have heard of in the media so Middle Eastern respiratory syndrome that comes to humans from camels or of course there's Hendra named after Hendra here in Brisbane is anyone here from Hendra no well you can be proud that you're famous to virologists worldwide i can actually tell you how to visiting PhD student and the first thing he wanted to do he was international PhD student when he arrived in brisbane was go to Hendra and take a picture of the Hendra site yeah again we have a great social life as religious I'm going to emphasize that now Hendra is originally thought to have come from bats and it seems to have crossed over into the human population occasionally going via horses so this problem of this animal human interface becoming increasingly burglary and these seems to increase over time and that's largely because as the human population continues to grow we continue to live and encroach upon spaces that we were never there we were never there before so all of a sudden we're exposing ourselves to new viruses from animals that our new system has never seen and we're not protected against the good news is that there are some intervention strategies that we can actually put in place to minimize the risk of this viral transmission events so for example in 2013 when a new strain of flu broke out in China and was infecting human population the Chinese government closed some live poultry markets and some of the major eastern cities in China and this actually reduced the risk of human transmission by 90% okay a dramatic drop in these transmission events but the downside of this is this is more of a short-term solution because obviously a large number of people actually depend on these poultry markets for their their livelihood their culture so instead some of the more long-term approaches the things like educational strategies teaching people who work in live poultry markets that you shouldn't sell will kill infected birds you should wear a face mask you should clean the cages you shouldn't transport birds or other animals between regions without consulting the appropriate quarantine authorities so I think given that this marks a hundred years since that terrible 1918 pandemic flu it's really important that we reflect upon what we've learnt in the last hundred years in terms of preventing viral disease and certainly we have made great strides in not only preventing viral disease but also detecting it and also treating it but I think maybe the biggest lesson that we can gleam over the last hundred years is that human and animal health is inextricably linked so it's only when we recognize that at all stages of governments and at all levels of research that we can hope to the next viral pandemic thank you very much [Music] you

Channel: ABC News (Australia)

Views: 399,770

Rating: 4.5422764 out of 5

Keywords: Australia, Ockham's Razor, Radio National, 1918 flu, Kirsty Short, pathogenesis, influenza, virus, Immunology, Microbiology, University of Queensland

Id: WIafYHjx04U

Length: 11min 0sec (660 seconds)

Published: Sun Apr 08 2018