0:00:05 > 0:00:06This is the story of
0:00:06 > 0:00:09one of science's most significant encounters.
0:00:10 > 0:00:13Pandemic disease borne by infectious bacteria,
0:00:13 > 0:00:16viruses and parasites.
0:00:18 > 0:00:22NEWSREEL: 'Is man to be defeated by something he cannot even see?'
0:00:22 > 0:00:25It is a story played out in an era of unprecedented technical change,
0:00:25 > 0:00:29in which new scientific advances
0:00:29 > 0:00:33have given us the tools to confront some of natures greatest threats.
0:00:33 > 0:00:35'Smallpox.
0:00:35 > 0:00:37'Poliomyelitis.
0:00:37 > 0:00:39'Influenza.'
0:00:39 > 0:00:41And where shifting national rivalries have shaped
0:00:41 > 0:00:44their implementation.
0:00:44 > 0:00:47We have seen every one of our worst predictions confirmed.
0:00:47 > 0:00:51Many of us felt like Cassandra who could see the future,
0:00:51 > 0:00:55could speak the future, would be listened to, but would not be believed.
0:00:55 > 0:00:58It is also a story of the television age,
0:00:58 > 0:01:01where each new wave of the disease reflects the changing nature
0:01:01 > 0:01:03of reporting.
0:01:03 > 0:01:08We've gone from 1,000 to 2,000 to 4,000 cases in just the course of a month.
0:01:12 > 0:01:17Science's battle with pandemic disease is an ongoing power struggle.
0:01:17 > 0:01:23Since its advent, television has been there for every success and failure.
0:01:41 > 0:01:47'Across the world, governments are taking emergency measures to try to contain the spread of swine flu.'
0:01:47 > 0:01:50One in three people in the UK could become infected.
0:01:50 > 0:01:54Swine flu has spread rapidly since it arrived here from Mexico.
0:01:56 > 0:02:02In March 2009, a new form of the H1N1 virus, called swine flu
0:02:02 > 0:02:09because of its similarity to a virus found in pigs, put the globe under the latest threat of a pandemic.
0:02:09 > 0:02:12In the last week, the number of cases has more than tripled.
0:02:12 > 0:02:15There will be more cases, and more deaths.
0:02:15 > 0:02:19It can no longer be contained. It's in the community and spreading, and it's here to stay.
0:02:19 > 0:02:24As a virologist, H1N1 shows all the sinister hallmarks of a pandemic.
0:02:24 > 0:02:29It's caused by a virus that's new to humans and to which we have no immunity.
0:02:29 > 0:02:37It can cause serious disease and is transmitted from person to person over a widespread area.
0:02:40 > 0:02:43Today, we are better equipped than ever to deal with such an outbreak.
0:02:43 > 0:02:48It is precious knowledge that has been hard won.
0:02:48 > 0:02:53Swine flu is just the latest in a long line of pandemics from smallpox to SARS.
0:02:55 > 0:03:00Outbreaks that can spiral around the world at ferocious speed.
0:03:01 > 0:03:08This is the story of these diseases seen through the lens of over 40 years of Horizon and BBC television.
0:03:11 > 0:03:13Although bacteria had been understood for centuries,
0:03:13 > 0:03:21it was the advent of electron microscopy in 1931 that allowed us to see a virus for the first time.
0:03:25 > 0:03:28If I prick my finger, like that...
0:03:28 > 0:03:33It was the beginning of a relationship between discovery and communication.
0:03:33 > 0:03:36Television made visible what science could see.
0:03:36 > 0:03:39..droplet of blood gradually forming on my finger.
0:03:39 > 0:03:44It would go on to chart every major scientific advance, and it was during this timeframe
0:03:44 > 0:03:49that we would learn more about disease than in our entire history.
0:03:49 > 0:03:51And it was just as well.
0:03:53 > 0:03:59In the mid-20th century, deadly microbes were one of the greatest threats to human health.
0:04:02 > 0:04:09Poor sanitation during the Second World War drove the reign of infectious disease.
0:04:09 > 0:04:15The need to conquer illness sparked a burst of scientific creativity.
0:04:17 > 0:04:23Resources were pumped into the newly-formed NHS and the development of antibiotics and vaccines.
0:04:23 > 0:04:27There was a new war to be won - the eradication of disease.
0:04:29 > 0:04:34'Instead of tanks and aeroplanes, they fight with microscope and test tube.
0:04:34 > 0:04:38'In their hands, victory and life.
0:04:38 > 0:04:42'Not death to the invading Nazi, but death to the insidious microbe.'
0:04:47 > 0:04:52In the decade after the war, television developed interest in this fight for public health.
0:04:57 > 0:05:03'The world is ours, or so we like to think. And why not?
0:05:05 > 0:05:07'Haven't we worked to make it ours?
0:05:09 > 0:05:12'Aren't we secure in our mastery?
0:05:16 > 0:05:23'We like to think so, but this flask denies us, for its contents could strike us down in thousands.
0:05:23 > 0:05:26'No, it is not a new type of bomb.
0:05:26 > 0:05:30'It is the smallest creature in the world, a virus.
0:05:30 > 0:05:33'The invisible enemy.
0:05:33 > 0:05:37'Is man to be defeated by something he cannot even see?
0:05:39 > 0:05:42'Are we winning, or losing?'
0:05:47 > 0:05:50The World Is Ours set the dramatic tone that would characterise many of the programmes that followed.
0:05:50 > 0:05:51And not without reason.
0:05:53 > 0:05:56This was a generation still in the grip of polio.
0:05:56 > 0:06:02This water-borne virus attacked the nervous system causing disability, often leading to death.
0:06:05 > 0:06:11'500 cases, 1,000 cases, 1,500 cases,
0:06:11 > 0:06:14'2,000 cases.
0:06:14 > 0:06:18'2,300 confirmed cases of poliomyelitis.'
0:06:18 > 0:06:24At its peak, 8,000 people were infected a year in the UK.
0:06:28 > 0:06:32My grandad was disabled by polio, and I grew up being shocked
0:06:32 > 0:06:36at how the effects of microscopic viruses could be so devastating.
0:06:36 > 0:06:42But by the mid-1950s, scientific optimism was paying off.
0:06:42 > 0:06:45Would this vaccine at last wipe the disease from our world?
0:06:45 > 0:06:52A new polio vaccine was showing that science was able to successfully overcome disease.
0:06:53 > 0:06:56A big step forward has been taken
0:06:56 > 0:07:01and we are confident that eventually poliomyelitis will be controlled by vaccination.
0:07:01 > 0:07:04Television celebrated this early triumph.
0:07:07 > 0:07:13Yet despite the progress, science's understanding of viruses remained rudimentary.
0:07:13 > 0:07:18Horizon took a detailed look at the challenges organisms were posing.
0:07:18 > 0:07:22'Viruses can only grow in a living cell.'
0:07:22 > 0:07:26They can't produce all their building blocks for themselves.
0:07:26 > 0:07:28They have to be parasitic
0:07:28 > 0:07:33on the building blocks, nucleic acids etc, of the cell.
0:07:33 > 0:07:37The virus has to enter the cell before it will grow
0:07:37 > 0:07:44and, in many respects, it's therefore protected by the cell and it replicates in the cell.
0:07:44 > 0:07:47It's only when it destroys the cell and the cell bursts,
0:07:47 > 0:07:51all these many virus particles come out to infect more cells.
0:07:51 > 0:07:54That's how the process of virus replication goes on.
0:07:54 > 0:07:59And the only way in which you can attack it
0:07:59 > 0:08:03is to destroy the building-up process of the virus.
0:08:03 > 0:08:10To do this without destroying the cell...very easy to give a poison to man that would kill the virus.
0:08:10 > 0:08:13It might kill the man as well.
0:08:14 > 0:08:21Because attempts to kill the virus could be harmful, the emphasis was on finding safe vaccines.
0:08:21 > 0:08:26I think every country or area ought to have at least one laboratory
0:08:26 > 0:08:30which is capable of, at very short notice,
0:08:30 > 0:08:35taking on the investigation of a dangerous infectious disease which appears
0:08:35 > 0:08:39because, from time to time, they're going to emerge
0:08:39 > 0:08:43and you want to examine the problem and find out what you can do.
0:08:43 > 0:08:49'In laboratories we visited all over Britain, we've also seen dramatic work on flu, as well as rabies,
0:08:49 > 0:08:53'on hepatitis as well as the hundred manifestations of the common cold.
0:08:53 > 0:08:59'And the new and improved vaccines we've seen are only the first results of this.
0:08:59 > 0:09:05'Despite the unknowns, there's a strong feeling of optimism, of excitement at the rate of progress.'
0:09:05 > 0:09:09It never stops. We began with the easy ones.
0:09:09 > 0:09:14After that, we had problems, because our techniques
0:09:14 > 0:09:18were not sufficient to show the viruses which we knew were there.
0:09:18 > 0:09:23We had to find new techniques to identify them, to show that they were there.
0:09:23 > 0:09:30It's most certain that new techniques will provide new openings for new vaccines.
0:09:30 > 0:09:33I'm very positive. Confident.
0:09:34 > 0:09:37But with experience came caution.
0:09:37 > 0:09:42The long-term effects of vaccines were still unknown
0:09:42 > 0:09:46and contaminated supplies had infected many of those they sought to protect.
0:09:46 > 0:09:50The important thing to make sure is that the risk of the vaccine
0:09:50 > 0:09:54is not greater than the risk of having the disease.
0:09:54 > 0:09:58This is the important thing, that the risk is worth taking.
0:10:00 > 0:10:05At the same time, the need for mass vaccination was taking off.
0:10:06 > 0:10:08The global population was multiplying.
0:10:08 > 0:10:12Packed cities became breeding grounds for disease,
0:10:12 > 0:10:15and travel - the perfect carrier.
0:10:17 > 0:10:25'It's only a matter of time before some exotic virus disease reaches Britain by intercontinental jet.'
0:10:28 > 0:10:33We had entered a new world, and so too had disease.
0:10:37 > 0:10:41And it wasn't just viruses taking their toll.
0:10:43 > 0:10:49In the 1970s, the world was in the throes of a cholera pandemic, a deadly bacterial intestinal disease
0:10:49 > 0:10:52indigenous to the Indian subcontinent.
0:10:56 > 0:11:02It was carried by contaminated food and water and spread by trade routes.
0:11:07 > 0:11:10By 1973, it had reached Italy.
0:11:12 > 0:11:14In the UK, it was making the news.
0:11:17 > 0:11:20'The disease is one of the most contagious in existence.
0:11:20 > 0:11:24'Even vaccination does not give 100% protection.'
0:11:24 > 0:11:28- Do you think all cholera cases are reported?- No, not by any means.
0:11:28 > 0:11:31It's an iceberg disease.
0:11:32 > 0:11:35Most cholera is probably relatively mild.
0:11:37 > 0:11:43It goes off as an attack of diarrhoea, and it's only when there are a lot of serious cases
0:11:43 > 0:11:47that it comes to note in the way in which it is now.
0:11:47 > 0:11:53When the tip of the iceberg gets, as it were, higher out of the water, we think there's an epidemic.
0:11:57 > 0:12:01Cholera was seen as a disease of poverty and industrialisation
0:12:01 > 0:12:06but, within nine years, it had been reported in 93 countries.
0:12:06 > 0:12:12To this day, it has yet to be eradicated, and a new strain of the bacterium
0:12:12 > 0:12:16is enjoying what is feared to be its latest pandemic in 11 countries.
0:12:19 > 0:12:22The West's close contact with disease raised questions
0:12:22 > 0:12:26about the responsibility of richer nations to the developing world.
0:12:27 > 0:12:30Horizon was early to engage in this ethical question.
0:12:32 > 0:12:37We do ignore the health of the Third World at our own peril.
0:12:37 > 0:12:39It will come back to haunt us.
0:12:39 > 0:12:44The virus that felled a child in a distant village yesterday
0:12:44 > 0:12:49can reach your own family today and be the seed of a global pandemic tomorrow.
0:12:51 > 0:12:57The will and resources to treat disease became part of a global political issue.
0:12:58 > 0:13:03And there is one pandemic that epitomises this more than most.
0:13:13 > 0:13:18Throughout history, malaria has killed more people than any other disease.
0:13:20 > 0:13:26It's caused by the plasmodium parasite and is spread by infected female anopheles mosquito bites.
0:13:26 > 0:13:31Its microscopic size belies its devastating impact on human health.
0:13:36 > 0:13:41Horizon repeatedly reported efforts to combat the disease.
0:13:41 > 0:13:45and in 1982 took an unflinching look at its impact in Sri Lanka.
0:13:46 > 0:13:48HE GROANS
0:13:51 > 0:13:55'Untreated, this man could expect convulsive shivering
0:13:55 > 0:14:00'and then a high fever every two days for several weeks.
0:14:00 > 0:14:03'Then later, he'd be likely to have relapses.'
0:14:17 > 0:14:22Malaria can also cause brain disease, anaemia and kidney failure,
0:14:22 > 0:14:25and still kills one million people a year.
0:14:27 > 0:14:33The first attempts to combat the disease were triggered by a different type of conflict.
0:14:36 > 0:14:43The US military were losing more soldiers to malaria than bullets in tropical war zones.
0:14:43 > 0:14:45So in the Second World War, they set out to develop
0:14:45 > 0:14:50a powerful insecticide and came up with a breakthrough - DDT,
0:14:50 > 0:14:53a substance that destroyed the nervous system of mosquitoes.
0:14:57 > 0:15:02In 1955, the World Health Organisation, the new global disease watchdog,
0:15:02 > 0:15:08used DDT to launch the world's first disease eradication campaign.
0:15:08 > 0:15:11Its aim - to wipe out malaria by the 1990s.
0:15:14 > 0:15:16It seemed to be working.
0:15:16 > 0:15:23Malaria was eradicated from North America and controlled in Southern Europe, Asia and Latin America.
0:15:23 > 0:15:29In Sri Lanka, cases dropped from almost three million to only 17.
0:15:29 > 0:15:33Victory seemed to be in sight.
0:15:33 > 0:15:38'Our children will be the first generation freed from the enslaving fever.'
0:15:38 > 0:15:41But science was up against a formidable enemy...
0:15:41 > 0:15:43evolution.
0:15:46 > 0:15:49Mosquitoes breed at a rapid rate.
0:15:49 > 0:15:53With each generation, comes the possibility of genetic mutation.
0:15:53 > 0:15:58Over time, mosquitoes build up resistance to insecticide.
0:15:58 > 0:16:03In 1969, the World Health Organisation gave up its fight.
0:16:03 > 0:16:06The worldwide eradication plan had failed.
0:16:09 > 0:16:14When the spraying was stopped, the mosquitoes returned with a vengeance.
0:16:16 > 0:16:23Having thought malaria had been wiped out in Sri Lanka in 1962, it was back.
0:16:23 > 0:16:3017 years later, scientists around the world started work on the ultimate dream - a vaccine.
0:16:30 > 0:16:38Progress in Sri Lanka was such that Horizon also reported on an experimental procedure under way.
0:16:41 > 0:16:47'These poor creatures are less fortunate than their human benefactors
0:16:47 > 0:16:51'for this troop of animals is heavily afflicted with malaria.
0:16:51 > 0:16:55'These monkeys have a completely separate parasitic strain
0:16:55 > 0:16:59'uniquely designed to invade their own body cells.
0:16:59 > 0:17:02'In the path toward a vaccine, monkeys are close to man,
0:17:02 > 0:17:06'but are safe for human researchers to try ways of making vaccines work.
0:17:08 > 0:17:12'They need the help of this woman and her cow
0:17:12 > 0:17:17'to attract and trap the other half of the monkey malaria system.
0:17:20 > 0:17:27'The job of the cow is to act as captive bait, to lure in a mosquito called Anopheles elegans
0:17:27 > 0:17:34'so that, in the night, when they're biting, the campaign's entomological teams can steal in to collect them.
0:17:36 > 0:17:39'All the mosquitoes want is a blood meal
0:17:39 > 0:17:45'and even then, if they do carry malaria, they can't infect the cow, so everyone else is safe.
0:17:48 > 0:17:55'When vaccines are developed, they will have to be tested against animal malarias.
0:17:57 > 0:18:01'Could this be the beginning of the end for human malaria too?'
0:18:04 > 0:18:08But like eradication, attempts at a human vaccine failed.
0:18:11 > 0:18:17The only hope of controlling the disease was with antimalarial drugs.
0:18:17 > 0:18:21In China, there had already been a breakthrough.
0:18:21 > 0:18:27A drug, Artemisinin, derived from an ancient plant was showing promise as a treatment.
0:18:27 > 0:18:32But it sparked huge scientific rivalry between the East and West.
0:18:36 > 0:18:40It wasn't until 2005 that Horizon was able to examine the truth of what happened.
0:18:43 > 0:18:47TRANSLATION: The foreigners seemed to be snooping.
0:18:49 > 0:18:52They were so arrogant and contemptuous.
0:18:55 > 0:19:00They were astonished that we Chinese had managed to achieve this amazing breakthrough
0:19:00 > 0:19:04when they'd spent so much time and effort on it and failed.
0:19:09 > 0:19:14Communist China was reluctant to share its discovery with its Cold War enemies.
0:19:14 > 0:19:18Particularly as members of the WHO committee responsible
0:19:18 > 0:19:21for anti-malaria drug development were members of the US military.
0:19:24 > 0:19:30China refused to release the plant or the drug to the rest of the world.
0:19:30 > 0:19:3515 years after its discovery, the drug was still unavailable to millions who needed it.
0:19:35 > 0:19:38It was very frustrating in the 1980s
0:19:38 > 0:19:43because here was a promising compound that many people wanted to work on, but yet we couldn't get it.
0:19:43 > 0:19:46It wasn't being sent out of China.
0:19:46 > 0:19:50It became clear that we needed another source for the compound.
0:19:53 > 0:19:57The new goal was to develop synthetic replacements.
0:19:58 > 0:20:01After years of trials, the artemisinin family of drugs
0:20:01 > 0:20:05became the world's frontline defence against malaria.
0:20:06 > 0:20:12Political divides had wasted time, but the ultimate weapon was still prevention.
0:20:12 > 0:20:15And there was increasing optimism about developing a vaccine.
0:20:15 > 0:20:22Horizon also followed an experimental trial in Mozambique which was showing promising results.
0:20:24 > 0:20:30'A vaccine that gives full protection against malaria is still some way off,
0:20:30 > 0:20:33'but it's no longer seen as impossible.
0:20:35 > 0:20:39'More than a dozen teams around the world are now chasing this great prize.'
0:20:40 > 0:20:43Does that mean we have a vaccine today?
0:20:43 > 0:20:48No. But it means that we're absolutely sure that it's possible.
0:20:48 > 0:20:51We just need to figure out the timing part of it.
0:20:54 > 0:21:00'In the meantime, Artemisinin, the Chinese wonder drug born of Cold War politics,
0:21:00 > 0:21:04'holds out the promise of a cheap, effective cure.
0:21:04 > 0:21:08'For the first time in a generation, science has delivered
0:21:08 > 0:21:11'an effective weapon to once again declare war on malaria.
0:21:14 > 0:21:18'It's a war that many scientists now believe we can win.'
0:21:19 > 0:21:23Yes, we can eradicate malaria. It's not going to be easy,
0:21:23 > 0:21:27but it can be done and we have the tools now to do that.
0:21:27 > 0:21:31Science appeared to be winning the war against nature.
0:21:35 > 0:21:39But in May 2009, television broke news of its latest defeat.
0:21:39 > 0:21:44Scientists say they've uncovered the first evidence that malaria spreading parasites are becoming immune
0:21:44 > 0:21:48to the world's most effective drug for treating the disease.
0:21:48 > 0:21:55The scientists say the resistance, discovered in Western Cambodia, has to be urgently contained
0:21:55 > 0:21:58because its spread could lead to a global health catastrophe.
0:22:02 > 0:22:10Despite its impact on human history, malaria has received only scant attention.
0:22:10 > 0:22:15Without effective treatment, the death rate could double in the next 20 years.
0:22:21 > 0:22:26We assume pandemics will have a beginning and an end.
0:22:26 > 0:22:28But few fit the model.
0:22:32 > 0:22:38In the 1980s, a new threat emerged, the scale of which would take years to realise.
0:22:38 > 0:22:46It first hit gay men in America who developed unusual diseases that didn't respond to treatment.
0:22:46 > 0:22:49GRID, or Gay Related Immune Deficiency as it was known,
0:22:49 > 0:22:55represented a potent brew of sex, death and sexuality.
0:22:55 > 0:22:58Horizon was the first British television programme
0:22:58 > 0:23:03to uncover the story of what would become known as AIDS.
0:23:06 > 0:23:14In 1983, Killer In The Village, followed science's first steps in understanding this new disease.
0:23:16 > 0:23:19The trail began in a leading American disease centre
0:23:19 > 0:23:22where a spate of similar symptoms had been causing alarm.
0:23:25 > 0:23:30'It was this rare pneumonia that first alerted the Centres for Disease Control in Atlanta, Georgia,
0:23:30 > 0:23:34'that something very odd was going on.
0:23:34 > 0:23:40'Usually, it's people like transplant patients, whose immune system is artificially depressed,
0:23:40 > 0:23:45'who sometimes get the pneumonia. Sandy Ford controls all supplies of the best drug for it.'
0:23:45 > 0:23:50I need your patient's name, age, sex, weight and the underlying reason for the immunosuppression.
0:23:50 > 0:23:54'In 1981, there was a sharp increase in the number of requests.'
0:23:54 > 0:23:57There's no underlying reason for the immunosuppression.
0:23:57 > 0:24:01'The drug is restricted and she's supposed to have a clear diagnosis.'
0:24:01 > 0:24:04He's not on chemotherapy for any malignancy?
0:24:04 > 0:24:08'Just checking. Chemotherapy also hits the immune system.
0:24:08 > 0:24:11'When this first happened, all she could think about
0:24:11 > 0:24:15'was her uncompleted paperwork, but then it happened again, and again.
0:24:15 > 0:24:19'In a matter of months, the unsatisfactory forms began to pile up.
0:24:19 > 0:24:24'The requests came mostly from around New York and from Los Angeles.'
0:24:24 > 0:24:26How about WBC count?
0:24:26 > 0:24:28'White blood cells.'
0:24:28 > 0:24:30- 2,000.- 'That's low!'
0:24:33 > 0:24:37There were other outward signs that something was seriously wrong.
0:24:39 > 0:24:46'Bobbi Campbell, a nurse in San Francisco, was one of the earliest AIDS victims still alive.
0:24:46 > 0:24:50'On a walking holiday he'd found what looked like a blood blister on his foot.
0:24:50 > 0:24:56'It didn't clear up so he showed it to a dermatologist who took a biopsy and diagnosed Kaposi's sarcoma.'
0:24:56 > 0:25:00I was devastated. I was 29 years old and I had cancer.
0:25:00 > 0:25:05I had a cancer that had killed a number of gay men in this country and some other countries.
0:25:05 > 0:25:09I felt like my death might be imminent, even though I felt fine.
0:25:09 > 0:25:14In the year since I've been diagnosed, three people that I know personally have died
0:25:14 > 0:25:18and each time it's a blow to the heart.
0:25:20 > 0:25:27'Pneumonias in LA, some cancers in San Francisco, both in New York, and all, it seemed, were gay.
0:25:29 > 0:25:33'Homosexuality has been around since ancient times.
0:25:33 > 0:25:36'But AIDS is new. So, why is it here?
0:25:36 > 0:25:39'Why now? And why them?
0:25:39 > 0:25:43'Is AIDS infectious? Can anything be done to stop it?
0:25:43 > 0:25:46'Can AIDS be cured?'
0:25:46 > 0:25:52As we gathered more and more patients, those patients would meet each other in the office.
0:25:52 > 0:25:55It became apparent that many of the patients
0:25:55 > 0:26:00had had contact with one or two, or perhaps more,
0:26:00 > 0:26:03other people who had the syndrome,
0:26:03 > 0:26:09which began to suggest to us that perhaps there was a sexually transmittable...
0:26:09 > 0:26:14a single sexually transmittable agent...
0:26:14 > 0:26:20that was being passed around in the community.
0:26:21 > 0:26:25Science was grasping at the possible causes of infection.
0:26:25 > 0:26:29Our most exciting hypothesis, and the one that we are working on most,
0:26:29 > 0:26:32is that, with the multiple exposure to sperm
0:26:32 > 0:26:36that homosexual men have from a variety of sources,
0:26:36 > 0:26:42both through the rectal route or through the oral route, and possibly absorption through the mucosa,
0:26:42 > 0:26:46that sperm is able to penetrate into the immune system or into the blood.
0:26:46 > 0:26:51'The most obvious public health message has been to avoid sexual contact
0:26:51 > 0:26:58'with anyone suffering from or even suspected of having AIDS. But since the disease may be hidden,
0:26:58 > 0:27:01'and casual, anonymous sex is still readily available
0:27:01 > 0:27:07'in many American cities, 175 gay doctors have endorsed this advice.
0:27:14 > 0:27:17'And all this applies to Britain too.
0:27:18 > 0:27:20DISCO MUSIC PLAYS
0:27:24 > 0:27:27'There is a great deal of travel between the world's gay communities.
0:27:27 > 0:27:31'A year ago, few British cases had been recorded.
0:27:31 > 0:27:35'Now, they number 40, with 22 dead.
0:27:35 > 0:27:38'Which means hundreds more with the complex.
0:27:40 > 0:27:43'The AIDS epidemic has a foothold here.'
0:27:48 > 0:27:54Whilst Horizon kept strictly to the science story, other coverage reported the social fallout.
0:27:55 > 0:27:58I don't like homosexual practices at all.
0:27:58 > 0:28:01I think it is a Godforsaken, unnatural, unhealthy,
0:28:01 > 0:28:03disease-ridden occupation.
0:28:03 > 0:28:08The AIDS virus has given us yet one more reason for wanting to minimise
0:28:08 > 0:28:10the amount of homosexuality in society.
0:28:10 > 0:28:17As a high proportion of AIDS victims are homosexuals, shouldn't homosexuality be made illegal?
0:28:17 > 0:28:22The only prevention is the castration of all homosexuals to avert the spread of this disease.
0:28:22 > 0:28:25The homosexual act is unnatural.
0:28:25 > 0:28:27It's perverted and it's incredibly filthy.
0:28:30 > 0:28:35Against this backdrop of homophobia, science continued to search for answers.
0:28:37 > 0:28:41I would like to ask Dr Gallow to come forward.
0:28:41 > 0:28:47In May 1984, an announcement by the United States Health Secretary made the headlines.
0:28:47 > 0:28:50There is, of course, important news.
0:28:50 > 0:28:54The probable cause of AIDS has been found.
0:28:55 > 0:28:59With the discovery came the hope that a cure was just round the corner.
0:29:02 > 0:29:07..process will enable us to develop a vaccine to prevent AIDS in the future.
0:29:07 > 0:29:10We hope to have such a vaccine ready for testing
0:29:10 > 0:29:12in approximately two years.
0:29:12 > 0:29:14Approximately two years.
0:29:17 > 0:29:20In 1986 there was still no vaccine
0:29:20 > 0:29:25and in AIDS - A Strange and Deadly Virus, Horizon explained why.
0:29:32 > 0:29:36'The AIDS virus is one of the simplest life-forms on the planet.
0:29:38 > 0:29:44'It belongs to an unusual family called retroviruses, only recently discovered to infect humans.
0:29:48 > 0:29:54'Within its spiky outer shell, is a protein core that protects the virus' genetic heart.
0:29:54 > 0:29:58'These foreign genes can pirate the cells that they infect.
0:29:58 > 0:30:04The viral genes are permanently inserted into the normal cellular DNA
0:30:04 > 0:30:08of the infected cell of the particular person that got infected.
0:30:08 > 0:30:12So that infection of that cell is forever because the viral genes
0:30:12 > 0:30:15are now part of the cellular genes, integrated right in.
0:30:16 > 0:30:21This integration occurs when the short chain of virus genes meets the DNA of the infected cell.
0:30:27 > 0:30:29The human cell is taken over.
0:30:29 > 0:30:34Sometime in the future, the inserted genes will make copies of the virus.
0:30:34 > 0:30:38Not only is that cell infected for a lifetime, when that cell divides,
0:30:38 > 0:30:41the daughter cells will also have not only the cell genes,
0:30:41 > 0:30:48but also the viral genes, so infection of the person is forever.
0:30:50 > 0:30:53The increasingly widespread transmission of the disease
0:30:53 > 0:30:57raised questions about whether this WAS a disease of homosexuality.
0:30:58 > 0:31:02'It's in Africa that the AIDS pandemic is at it's most acute.
0:31:02 > 0:31:05'It's hard to believe that homosexuality or drug abuse
0:31:05 > 0:31:08'can account for the millions infected with the AIDS virus there.'
0:31:08 > 0:31:12I have become more convinced than I was before,
0:31:12 > 0:31:17that AIDS in Africa is transmitted principally by sexual contact.
0:31:17 > 0:31:21And principally by heterosexual contact.
0:31:21 > 0:31:28There may be other factors such as the re-utilisation of hypodermic needles that haven't been properly
0:31:28 > 0:31:35sterilised and some people have said perhaps insects, biting insects like mosquitoes, might spread the virus.
0:31:35 > 0:31:39But the one thing that has come through loud and clear is that AIDS is spreading
0:31:39 > 0:31:47in the most sexually active people in a community and particularly amongst the promiscuous.
0:31:47 > 0:31:55Mosquitoes and needles do not select between those people so very much, so I think it still comes down to
0:31:55 > 0:32:00saying if you want to avoid AIDS, avoid having too many sexual partners.
0:32:05 > 0:32:08Despite a promising drug called AZT
0:32:08 > 0:32:12and experiments in animals to find a vaccine,
0:32:12 > 0:32:13the virus was fighting back.
0:32:17 > 0:32:21'Just like influenza, it seems the AIDS virus can mutate
0:32:21 > 0:32:24'to evade the body's defences.
0:32:24 > 0:32:27'The protein spikes are what count in the immune response.
0:32:28 > 0:32:33'Key points on the surface of these proteins are recognised by the antibodies.
0:32:33 > 0:32:37'By mutating at precisely such places, an extremely small change
0:32:37 > 0:32:39'in the virus can defeat antibodies
0:32:39 > 0:32:43produced both naturally and by a vaccine.
0:32:43 > 0:32:46'Antibodies made to the old configuration no longer bind,
0:32:46 > 0:32:49'and the virus can stay one jump ahead of the immune system.
0:32:50 > 0:32:53'And there's a second reason to doubt a vaccine will work.
0:32:53 > 0:32:57'The AIDS virus can escape detection by the immune system
0:32:57 > 0:33:01'if it enters the body inside a cell from another person.
0:33:01 > 0:33:04'This foreign cell is then engulfed by a scavenging,
0:33:04 > 0:33:08'slug-like macrophage, and so, the AIDS virus passes
0:33:08 > 0:33:13'directly from the cell to cell, bypassing any antibodies in the blood.
0:33:13 > 0:33:15It seemed that the virus could outwit
0:33:15 > 0:33:17even the most cutting edge science.
0:33:17 > 0:33:20We're in the presence of an epidemic for which we have no vaccine
0:33:20 > 0:33:23and no effective treatment. That's as simply as I can put it.
0:33:28 > 0:33:32More than 20 years on, the hunt for an effective vaccine has failed.
0:33:37 > 0:33:43We now know that AIDS is much more than a sexually transmitted disease.
0:33:43 > 0:33:46Whilst antivirals may slow its progress, they can't stop it.
0:33:49 > 0:33:55We've since learnt that HIV exploits its ability to mutate, more than any other virus.
0:33:58 > 0:34:04Untreated, HIV makes 10 billion new virus particles in one person in one day.
0:34:04 > 0:34:08Coupled with its high mutation rate, it means there are many variants of the virus.
0:34:08 > 0:34:12More than any single vaccine can contend with.
0:34:14 > 0:34:19Since Horizon's first contact with AIDS, it's killed over 25 million people worldwide,
0:34:19 > 0:34:24making it one of the most destructive pandemics in history.
0:34:25 > 0:34:28Few pandemics present such a challenge.
0:34:29 > 0:34:34Thanks to a combination of global cooperation and some centuries-old science,
0:34:34 > 0:34:38we were able to halt one of history's most feared diseases.
0:34:47 > 0:34:49The cause is in this container.
0:34:49 > 0:34:51The world's most violent killer.
0:34:52 > 0:34:54The smallpox virus.
0:34:57 > 0:35:02Unlike HIV, the Variola virus that causes smallpox barely mutates,
0:35:04 > 0:35:09and in the 18th century scientists were able to produce the world's first ever vaccine.
0:35:13 > 0:35:21200 years later, the WHO had a bold plan - to vaccinate every single person at risk.
0:35:21 > 0:35:22All billion of them.
0:35:22 > 0:35:28In 1997, Horizon celebrated this extraordinary feat
0:35:28 > 0:35:31and went to meet the scientist behind it all.
0:35:32 > 0:35:37I felt overawed by the task ahead, recognising we had so many languages
0:35:37 > 0:35:42to deal with, that we had so many different countries to deal with.
0:35:42 > 0:35:48We were dealing with countries where there was famine, where there was war, wherever it was, whether
0:35:48 > 0:35:51there was even organised civil government there, we had to go.
0:35:56 > 0:36:02There were many scientists who said that this was just not possible to do.
0:36:02 > 0:36:07In fact, at the time, even the director-general of the WHO, said, it just can't be done.
0:36:10 > 0:36:14In a phenomenal effort, a team of hand-picked doctors
0:36:14 > 0:36:17worked tirelessly to vaccinate or treat every case of smallpox.
0:36:19 > 0:36:25Having vanquished smallpox in Ethiopia, India, Bangladesh and every other country,
0:36:25 > 0:36:30the searchers were on the trail of the very last strain in Somalia.
0:36:34 > 0:36:37They tracked the virus to this village.
0:36:38 > 0:36:42And then to this woman who had infected her two babies.
0:36:42 > 0:36:45One died, but this child survived.
0:36:46 > 0:36:48They traced all her contacts,
0:36:48 > 0:36:50and that is when they found him.
0:36:54 > 0:37:00Ali Malin, the last person on the planet with smallpox.
0:37:00 > 0:37:02He survived.
0:37:03 > 0:37:06We reached the point where we had found the last case,
0:37:06 > 0:37:11and eight weeks had gone by, there were no more cases, nobody could
0:37:11 > 0:37:15find anything, we suddenly realised that it was over.
0:37:16 > 0:37:19It was deemed a public health miracle.
0:37:19 > 0:37:24By 1979, smallpox was the first infectious disease to have ever been eradicated from the wild.
0:37:26 > 0:37:29Millions of lives had been saved.
0:37:30 > 0:37:34The virus was so dangerous, that stocks of it would only be kept
0:37:34 > 0:37:39in two WHO approved laboratories in America and in Russia,
0:37:39 > 0:37:42after which they would finally be destroyed.
0:37:45 > 0:37:51During the 1980s, it became clear to everyone
0:37:51 > 0:37:54that there was a building pressure on the part of all countries...
0:37:54 > 0:38:02to come to the end of this programme and draw a line with the destruction of the virus.
0:38:02 > 0:38:07So the US scientists and Russian scientists who at that time
0:38:07 > 0:38:12had the virus, worked out a series of steps to be taken...
0:38:12 > 0:38:18to make sure that we had characterised the virus as carefully as we could
0:38:18 > 0:38:23and a total DNA map of the virus began to be constructed.
0:38:25 > 0:38:30It was decided that this could all be done by the end of December 1993.
0:38:39 > 0:38:431993 arrived and the work wasn't completed.
0:38:43 > 0:38:49The decision to destroy the stocks was postponed because something extraordinary happened.
0:38:49 > 0:38:54When scientists compared the genes in the pox viruses to those in gene banks
0:38:54 > 0:38:57they found genes in common with our own.
0:39:00 > 0:39:05What became clear is that within these genes
0:39:05 > 0:39:10were instructions that seemed to have been hijacked from the host immune response.
0:39:10 > 0:39:13In other words, these viruses were mimicking the host.
0:39:13 > 0:39:16They had stolen components
0:39:16 > 0:39:20from the immune and inflammatory response, and this was
0:39:20 > 0:39:26really an astounding realisation, a new level of complexity, something none of us were prepared for.
0:39:30 > 0:39:36When cells are invaded by a virus they send out warning signals which lock onto receptors
0:39:36 > 0:39:40on the healthy cells around them and give instructions to protect them from attack.
0:39:44 > 0:39:51Amazingly, the pox viruses steal our genetic information and manufacture their own decoy receptors.
0:39:51 > 0:39:54So the messages directed at the healthy cells are swept up
0:39:54 > 0:39:58by the virus' fake receptors and the warning never gets through.
0:40:00 > 0:40:05There was a dawning of recognition that these beasts had tricks
0:40:05 > 0:40:10that we had never seen before and it was sort of a thrilling time.
0:40:12 > 0:40:15With this growing list of discoveries, it dawned
0:40:15 > 0:40:21on the scientific community that the virus understood us better than we understood ourselves.
0:40:26 > 0:40:31Scientists now began to feel that the smallpox virus might be too precious to destroy.
0:40:42 > 0:40:47If we could study the virus to learn how it gained control of our immune system,
0:40:47 > 0:40:52we might be able to unlock clues to other viruses and ultimately cure ourselves.
0:40:53 > 0:40:56We're looking at a whole new way of treating disease.
0:40:56 > 0:41:00I think these viruses have illustrated for us,
0:41:00 > 0:41:06the principles of decoy receptors, the principles of...tinkering
0:41:06 > 0:41:10in subtle but clever ways with the host response.
0:41:10 > 0:41:16And I think they are leaving the way to showing us whole new ways of making drugs and treating disease.
0:41:20 > 0:41:24Over at the high security laboratory in Siberia
0:41:24 > 0:41:26this idea has caused excitement.
0:41:31 > 0:41:34TRANSLATION: We can synthesise individual proteins and use them
0:41:34 > 0:41:36for future pharmaceuticals.
0:41:38 > 0:41:44The smallpox virus is an outstanding example of this.
0:41:44 > 0:41:49It could be used to treat severe diseases that are now virtually untreatable.
0:41:49 > 0:41:54Such as septic shock, cerebral malaria, rheumatoid arthritis,
0:41:54 > 0:41:58acute AIDS-related conditions and so on.
0:41:58 > 0:42:02And this is what we are working on now.
0:42:07 > 0:42:12There are many more genes that we have yet to study in the smallpox virus.
0:42:12 > 0:42:14Each of which might lead to new drugs.
0:42:16 > 0:42:18But there is something more.
0:42:18 > 0:42:23These genes may tell us how all other deadly viruses attack us.
0:42:23 > 0:42:26Because smallpox uses every trick there is.
0:42:33 > 0:42:36On May 24th 1996,
0:42:36 > 0:42:42WHO gathered to decide finally the fate of the smallpox virus.
0:42:47 > 0:42:51TRANSLATION: If WHO decides to take this fateful step
0:42:51 > 0:42:56and destroy such a unique subject for research as the smallpox virus,
0:42:56 > 0:43:02it will confirm to me that the world isn't ruled by reason, but by bureaucracy and politics.
0:43:08 > 0:43:12Ladies and gentlemen, are there any comments on this?
0:43:12 > 0:43:18I see none, then the resolution has been approved.
0:43:20 > 0:43:22APPLAUSE
0:43:22 > 0:43:25On June 30th 1999,
0:43:25 > 0:43:28all the stocks of smallpox will be destroyed.
0:43:30 > 0:43:34And research on the live virus will end forever.
0:43:40 > 0:43:42The stocks weren't destroyed.
0:43:42 > 0:43:48And what they tell us about killer viruses is still being used in a hunt for the AIDS vaccine.
0:43:48 > 0:43:51But smallpox was spared for a different reason.
0:43:51 > 0:43:58After 9/11 the world changed, and the virus could be used as a lethal weapon by bioterrorists.
0:43:58 > 0:44:03Scientists needed to understand the virus to protect our global security.
0:44:03 > 0:44:09But, to my mind, the boundary between fear and the true threat of disease was blurring.
0:44:11 > 0:44:16We had entered a new digital age in which internet rumours
0:44:16 > 0:44:20and rolling news spiralled fear of the next pandemic.
0:44:20 > 0:44:24By 2002 the world was poised for global attack.
0:44:24 > 0:44:27They are struggling to contain the epidemic.
0:44:27 > 0:44:31We've gone from 1,000 to 2,000 to 4,000 cases in just the course of a month.
0:44:31 > 0:44:35And a new threat did emerge. Not from bioterrorism,
0:44:37 > 0:44:39but from nature.
0:44:43 > 0:44:45SARS is the story of the modern plague.
0:44:45 > 0:44:51A virus that seemed to come from nowhere and spread panic throughout the world.
0:44:51 > 0:44:54It began when a life-threatening pneumonia,
0:44:54 > 0:44:59Severe Acute Respiratory Syndrome, began to spread through China.
0:45:00 > 0:45:05It was declared a bigger threat than AIDS, heralding a rapid hunt to track down the cause.
0:45:07 > 0:45:11By now, science had a new weapon in its armoury -
0:45:11 > 0:45:14rapid genetic decoding.
0:45:14 > 0:45:20Horizon recounted the steps science had taken to contain this emerging threat.
0:45:24 > 0:45:29On the 15th March, the WHO announced a worldwide alert.
0:45:32 > 0:45:36This was something the WHO had never done before.
0:45:36 > 0:45:43The alert meant the mystery virus was now declared an official threat to everyone on the planet.
0:45:45 > 0:45:49We had to react to an urgent public health need,
0:45:49 > 0:45:53so we were all very worried and we knew that this was
0:45:53 > 0:45:56a race against time, so we had to find very quickly,
0:45:56 > 0:46:00the pathogen, the causative agent for this disease.
0:46:02 > 0:46:07All the labs had agreed to forgo their rivalries and collaborate.
0:46:07 > 0:46:10For the first time in history,
0:46:10 > 0:46:13the full force of the world's scientific might was united
0:46:13 > 0:46:18and focused on identifying just one disease.
0:46:24 > 0:46:26But as the detective work progressed,
0:46:26 > 0:46:28the disease continued to spread.
0:46:32 > 0:46:38By the 20th March, 306 people around the world were infected.
0:46:41 > 0:46:43And a disturbing statistic was emerging.
0:46:45 > 0:46:49SARS killed about 4% of its victims.
0:46:49 > 0:46:50One in 25.
0:46:57 > 0:47:00But then came more encouraging news.
0:47:04 > 0:47:09There was a breakthrough in the hunt for the cause of SARS.
0:47:17 > 0:47:22A team in Hong Kong had isolated a virus from a SARS patient.
0:47:24 > 0:47:29Using a technique called random polymerase chain reaction,
0:47:29 > 0:47:33scientists then tried to identify this virus.
0:47:35 > 0:47:40They took tiny strands of DNA from hundreds of different known viruses
0:47:40 > 0:47:46and began testing them, one after another, to see if any of them matched the mystery virus.
0:47:50 > 0:47:55They struck lucky. The normally benign virus they identified
0:47:55 > 0:47:58was more often known for the common cold.
0:48:00 > 0:48:05But it's also carried by animals, which in China live side by side with people.
0:48:05 > 0:48:09If the virus mutates, it can make the deadly leap to humans.
0:48:14 > 0:48:20These viruses that jump across from animals to people can be utterly lethal.
0:48:22 > 0:48:27Our immune systems are simply unprepared for the threat of the new.
0:48:30 > 0:48:33It's how most killer diseases come into existence
0:48:35 > 0:48:40and it may well be how SARS was unleashed on the world.
0:48:41 > 0:48:48On the 12th of April, just 20 days after the discovery of the SARS Corona virus, a team in Canada
0:48:48 > 0:48:53announced they'd cracked the virus's entire genetic code.
0:48:56 > 0:49:01Never in the history of science has a new disease been sequenced so quickly.
0:49:03 > 0:49:06We've been able within four weeks
0:49:06 > 0:49:10to detect the culprit,
0:49:10 > 0:49:12to nail it down, to sequence it.
0:49:12 > 0:49:15I have never seen anything like this before.
0:49:15 > 0:49:18It's been staggering how quickly we're moving.
0:49:21 > 0:49:23It could be a huge step
0:49:23 > 0:49:26towards designing a cure.
0:49:35 > 0:49:38Already the genetics has thrown up some hopeful news.
0:49:40 > 0:49:42The virus is barely mutating at all.
0:49:43 > 0:49:46It is virtually the same from Hong Kong to Canada.
0:49:48 > 0:49:51That means it should be easy to design specific drugs for it,
0:49:51 > 0:49:56as unlike the virus causing AIDS, it's not a rapidly moving target.
0:49:56 > 0:49:59From what we know so far,
0:49:59 > 0:50:05it looks as though the virus would be stable enough that vaccine development is a viable option.
0:50:05 > 0:50:09In the meantime, with intimate knowledge of how the virus spread,
0:50:09 > 0:50:12scientists came up with a strategy to contain it.
0:50:12 > 0:50:14A simple one.
0:50:14 > 0:50:21Mass quarantine and infection control became the most effective ways to defeat the disease.
0:50:24 > 0:50:31All over the world, countries coordinated their fight back against the disease.
0:50:31 > 0:50:36It really is a good news, sort of tingly, human story.
0:50:36 > 0:50:40Seeing the world, which is often so fragmented, pulling together
0:50:40 > 0:50:42to try and fight this common cause.
0:50:42 > 0:50:46They managed to arrest the virus and the last case was reported
0:50:46 > 0:50:49in May 2004.
0:50:49 > 0:50:54SARS claimed just 800 lives worldwide, whereas 5,000 people die
0:50:54 > 0:50:57from flu each year in Britain alone.
0:50:59 > 0:51:05Human trials for a vaccine are under way, should a SARS pandemic ever return.
0:51:13 > 0:51:20The success of halting SARS reminded us of both science and the power of global cooperation.
0:51:20 > 0:51:27It was to be a dress rehearsal for an even greater fear that was lurking just around the corner.
0:51:35 > 0:51:38In 2003, we faced another deadly threat.
0:51:40 > 0:51:43The H5N1 virus, or bird flu.
0:51:44 > 0:51:46Science had moved on and our knowledge of viruses
0:51:46 > 0:51:53meant that we no longer had to wait for a disease to go pandemic to imagine its hypothetical future.
0:51:53 > 0:51:59This was the science of prediction and it wasn't long before television followed suit.
0:52:04 > 0:52:08In a departure from the norm, Horizon merged drama with science
0:52:08 > 0:52:13to present a fictionalised account of science's worst case scenario.
0:52:16 > 0:52:22We're talking about a massively increased number of deaths per day over what we would normally see.
0:52:22 > 0:52:25That would be happening everywhere.
0:52:26 > 0:52:32We will very quickly overwhelm our mortuaries, our morgues, our funeral homes and our cemeteries.
0:52:32 > 0:52:36Our schools, which are places of laughter and life,
0:52:36 > 0:52:37will become morgues.
0:52:37 > 0:52:42Families, where everybody's sick and the mother or the father can't even
0:52:42 > 0:52:46take care of the child, I think that's so foreign
0:52:46 > 0:52:51to our concept of life, that we can't imagine it.
0:52:55 > 0:53:01The basis for this fearsome scenario was the fact that H5N1
0:53:01 > 0:53:04a virus found in Chinese bird flocks,
0:53:04 > 0:53:08had in a few instances made the deadly leap to humans.
0:53:12 > 0:53:19This particular H5N1 virus, falls into the category of what we call a highly pathogenic virus.
0:53:19 > 0:53:24When we analysed it, we found a tiny extra piece of genetic material
0:53:24 > 0:53:27that's in one of the genes of the virus.
0:53:28 > 0:53:31This very small change allows the virus to spread
0:53:31 > 0:53:34beyond the respiratory tract.
0:53:34 > 0:53:39Many of these people who have become infected with H5N1 are dying from multi organ failure.
0:53:41 > 0:53:44For this hypothetical pandemic to become real,
0:53:44 > 0:53:48the virus would have to undergo further mutation,
0:53:48 > 0:53:52one that would enable human-to-human transmission.
0:53:52 > 0:53:58This H Protein right now cannot attach very easily to human cells
0:53:58 > 0:54:01and cannot spread from one human to another.
0:54:01 > 0:54:06The best scientific estimate is that one or two mutations
0:54:06 > 0:54:11will be enough to allow this virus to attach easily to human cells...
0:54:11 > 0:54:12HE SNEEZES
0:54:12 > 0:54:17When we cough or sneeze we'll easily transmit it to another human being,
0:54:17 > 0:54:21and it'll ripple through like a wildfire in the population.
0:54:22 > 0:54:26When the scientists set their virtual flu virus free
0:54:26 > 0:54:32in the world they had created, the results were far reaching... and devastating.
0:54:32 > 0:54:37What happens is as the rate of infection increases, the colours change from yellow to red.
0:54:37 > 0:54:40And you're starting to see hotspots here
0:54:40 > 0:54:46of masses of red dots, meaning that there's a very high incidence of infected people in those areas.
0:54:46 > 0:54:52By the time we get to about three months in, the incidence of pandemic influenza reaches its peak.
0:54:52 > 0:54:54It's no longer just in the major cities.
0:54:54 > 0:54:59Basically, the entire country is experiencing a very severe outbreak.
0:55:00 > 0:55:05In just three months, the entire country was overrun.
0:55:05 > 0:55:10The sea of red dots leave very little to the imagination.
0:55:11 > 0:55:15With a mortality rate of 60% for those infected,
0:55:15 > 0:55:21H5N1 bore many of the hallmarks of the most devastating disease episode in history.
0:55:22 > 0:55:24The Spanish Flu of 1918.
0:55:26 > 0:55:32At the moment with H5N1, 140 people have died in a population of six billion.
0:55:32 > 0:55:35People come to me and say, "that's not many."
0:55:35 > 0:55:40But my answer to that is, go back to the year before 1918,
0:55:40 > 0:55:46there you had 140 people dead, but within a year it exploded
0:55:46 > 0:55:49and killed 50 million people.
0:55:49 > 0:55:52So there's a warning there.
0:55:52 > 0:55:57We can't ignore a virus that has done that in the past, we really can't.
0:55:57 > 0:56:04If this H5N1 virus mutates to be anything like the 1918 virus,
0:56:04 > 0:56:11the number of new infections and deaths will double every three days.
0:56:14 > 0:56:19I think until you believe that every tenth person in your community
0:56:19 > 0:56:21could die next month
0:56:21 > 0:56:26of a disease they have no control over, until you really believe that,
0:56:26 > 0:56:28how are you going to prepare for it?
0:56:31 > 0:56:34Thankfully, these worst fears have never materialised.
0:56:34 > 0:56:39A pandemic of the scale imagined here is an extremely unlikely event.
0:57:00 > 0:57:06Pandemics challenge our deep-seated belief that we are in control of nature.
0:57:06 > 0:57:10Despite our technological advances, we still only successfully
0:57:10 > 0:57:14eradicated one disease, smallpox, from history.
0:57:14 > 0:57:19Pandemics will continue to be a biological and mathematical certainty.
0:57:19 > 0:57:25In the age-old battle between science and disease, it seems disease is still winning.
0:57:31 > 0:57:34Subtitles by Red Bee Media Ltd
0:57:34 > 0:57:36E-mail subtitling@bbc.co.uk