CONTAGION

This is an excerpt from my book ABSOLUTE DISASTERS, published in 2017 at a time when we didn’t talk much about Coronaviruses. If you want to know more it is available on Amazon.

Anyone who saw Dustin Hoffman play a manic and obnoxious doctor from the US Centres for Disease Control (CDC) in the film Outbreak, or Kate Winslett in the more recent and realistic film Contagion will understand why there is reason to be alarmed about the threat posed by emerging infectious diseases. Emerging and re-emerging infectious diseases are those that are resistant to all known antibiotic therapies and/or for which the population has little or no immunity.

Influenza – the ‘Flu’ – will be the most likely cause of any future killer pandemic. And epidemiologists agree that it is not a question of ‘whether’ but ‘when’ such a killer will strike. We’re not talking about the kind of Flu that knocks us out for a few days every other winter, but a mutated strain against which we have no built-in immunity and for which there is neither cure nor vaccine.

That’s why Avian and Swine Flu caused such a commotion a couple of years ago, with the UN scaring the wits out of the world by suggesting that up to 150 million people could die. But statistical regression models clearly demonstrate that they were right then and they are right now. The threat has not receded.

Two recent outbreaks – the 2009 H1N1 Swine Flu and the H5N1 Bird Flu that emerged in Asia a few years earlier – failed to become the global killers predicted by the UN even though millions were infected. Bird flu was much the more virulent of the two, killing about half of those infected, and the fear is now that there will be a global resurgence that combines the virulence of the H5N1 with the transmissibility of the H1N1. The Spanish Flu of 1918 was one such “doomsday strain”, killing between 50 million and 100 million people; around 4%-7% of the world’s population at the time and many times more than were killed in the First World War.

It is easy to imagine the mass panic that would result if something similar to ‘Spanish Flu’ were to emerge again. Power-station workers, doctors, delivery drivers, water treatment engineers, and petrol station managers would either be sick or dead. Hospitals would close their doors. The lights would go out, the shops would be empty, and cities would grind to a halt. With people fleeing to remote rural areas, law and order would break down. This is the scenario so vividly – and, according to CDC in Atlanta, so accurately – portrayed in the film Contagion.

Less than 2% of viruses that exist in the wild are known about.

According to the US Institute of Medicine, if the next major infectious disease is not from a previously unknown bug, the biggest threat comes from HIV-AIDs, Hepatitis-C, Tuberculosis (TB), and new, more lethal variants of Coronavirus, including Influenza. They also think that hospital acquired infections will also pose a growing threat as drug resistance increases and new strains of Streptococcus or Staphylococcus emerge. Already, there is only one antibiotic left that controls spread of the “super-bug” Staphylococcus aureus, and there are signs that even this is losing its effectiveness. TB, cholera, and malaria are not only beginning to make a comeback, but are doing so with more virulent and drug-resistant forms.

In reality, there are bugs out there which can kill up to 80% or more of all people they come into contact with, and for which there is no cure. Except for the most exotic – by which we normally mean ‘deadly’ – you will have heard of most of them: Influenza, AIDS, Ebola, and Bubonic Plague, for example. They may well ‘self-limit’ – i.e die out on their own accord – but not before millions are dead or dying.

But you are unlikely to have heard of Henipah, a particularly nasty form of virus found originally in fruit bats. Fruit bats have evolved with this virus over millions of years, and because of this co-evolution, they experience little more from it than the fruit bat equivalent of a cold. But once the virus breaks out of the bats and into a species that hasn’t evolved with it, a horror show can take place, as one did in rural Malaysia in 1999. It is probable that a bat dropped a piece of saliva-covered fruit into a forest piggery. The pigs became infected with the virus, and then amplified it. And then it jumped to humans. It was startling in its lethality. Out of 276 people infected, 106 died and many others suffered permanent and crippling neurological disorders. There is no cure or vaccine. Since then there have been twelve similar, though thankfully smaller, outbreaks in South Asia.

There are many more diseases with more familiar names such as Measles, Pertussis (Whooping Cough), Diptheria, Tuberculosis, Yellow Fever and others, which kill an awful lot of people around the world every year, but about which we hear little because we think that vaccination has incurred life-long immunity. Diptheria in particular is making a comeback in countries of the former Soviet Union where health infrastructure is crumbling and vaccination coverage is a shambles. In developed countries, the situation is not much better, with vaccination coverage rates one third of what they should be to ensure ‘herd’ immunity^[1].

Politics and trade also play their part. Intellectual property rights are frequently flouted by manufacturers in developing countries who make generic copies of drugs that are under patent protection, not always with the permission of the patent-holder. Some of the drugs manufactured in this way contain no active ingredient, or contain half the prescribed dose … which is worse in many ways, as it fails to cure and stimulates resistance at the same time [see Disaster Misperception # 77].

Nearly two-thirds of emerging infectious diseases that affect humans originate in animals, with more than two-thirds of those originating in wild animals. The scope of the challenge this presents is huge and complex, not least because it is estimated that only one percent of viruses that exist in wildlife are known. And, with modern air travel and a robust market in wildlife trafficking, the potential for a serious outbreak in a large population centre is growing all the time. Increased ease of travel – one million humans are in the air at any one time – has radically altered the speed at which microbes can meet and recombine, and rendered us hideously susceptible to what results. Today, an aggressive transmissible influenza with an incubation period of a few days could be on every continent within 36 hours.

In other words, outbreaks of potentially deadly diseases reflect what we are doing, either deliberately or unwittingly, rather than just being things that happen. In this – and as the Ebola epidemic so vividly demonstrated – epidemics are no different to any other form of so-called ‘natural’ disaster.

We live in a world that, at least from the point of view of a virus or a bacterium, has changed very little. Our world remains fraught with the risk of new pandemics as microbes that have never encountered each other before combine to form mutant stains which will cause diseases capable of spreading in ways neither of their ‘parents’ could ever do.

The appearance of a virus capable of infecting 40% of the world’s population, and killing unimaginable numbers of them is not as far-fetched scenario as you might think. This is what Laurie Garrett said about Bird Flu (Avian Influenza) when it was making headline news in the years after 2005:

“The havoc such a disease could wreak is commonly compared to the devastation of the 1918-19 Spanish Flu, which killed over 50 million people in 18 months. But avian flu is much more dangerous. Doom may loom. But note the ‘may’. If the relentlessly evolving (H5N1) virus becomes capable of human-to-human transmission, develops powers of contagion typical of human influenzas, and maintains its extraordinary virulence, humanity could well face a pandemic unlike any ever witnessed.

Or nothing could happen at all.

Scientists cannot predict with any certainty what this virus will do. Evolution does not function on a knowable timetable, and influenza is one of the sloppiest, most mutation-prone pathogens in nature’s storehouse”.

Meanwhile, a horse dies mysteriously in Canada, a chimpanzee in Central Africa, a few pigs in Australia, and whole flocks of chickens in Indonesia. People in regular contact with these animals fall sick, and most die. These real-life cases, and others involving bats and unknown numbers of even more exotic species, represent not just isolated events, but a trend in the transmission of new diseases from animals to humans.

International health experts call such diseases ‘zoonotic’, meaning animal infections that somehow cross over to infect people. About one third of the 15,000 or so diseases known to man – including the modern day scourges of malaria, HIV, and more recently, Ebola – are in this category. For the most part, these diseases are the result of infection by one of three types of pathogen or bug: viruses, bacteria, and fungi. The most troublesome are viruses, mostly because of their abundance, their ability to adapt quickly, and the fact that they don’t respond to antibiotics. In the 1995 film Outbreak, a sweet little Capuchin monkey carrying a “deadly virus” that was going to cause “the greatest medical crisis in the world” caused anxiety in millions of cinema-goers. The film gave zoonotic infections the Hollywood treatment but stripped of the hyperbole, it contained elements of reality. Zoonoses are a major threat to human health, and it is considered “highly likely” that the next pandemic will originate from an animal, as Ebola did.

Within the viral camp, there are two main sub-groups, the DNA and RNA^[2] viruses, with the RNA viruses being particularly worrisome. HIV-AIDS is caused by a zoonotic RNA virus. So was the Spanish Flu Laurie Garrett referred to above. And so are Ebola, Marburg, Lassa, West Nile, Dengue, Rabies, Yellow Fever, SARS, and all those other spooky names which strike the fear of God into anyone who has seen blood oozing from Kevin Spacey’s eyes after being infected by some unidentified bug in the movie Outbreak.

There are an awful lot of RNA viruses. They exist in the oceans, in rivers, in the soil, in forests, and in urban jungles. According to Professor Eddie Holmes of Penn State University, one of the world’s leading virologists, it’s possible that every species on the planet, bacterium, fungus, plant, and animal, supports at least one RNA virus, though, as he puts it, “we don’t know for sure because we’ve only just started looking.”

It is only fairly recently that marine biologists have come to realise that the open ocean is teeming with viruses of a surprisingly wide range of types. Not all of these viral particles are infectious, as ultra-violet radiation inactivates most of them in the photic zone. However, the energy surge that is a tsunami cascades water from great depths and unleashes it into a completely alien environment that includes oxygen and sunlight. In this environment, viruses not usually encountered collide with wounded or drowning humans to cause illnesses not usually seen^[i].

We do know, however, that influenza viruses – which are RNA viruses – can be lethal and that there are three types, rather unimaginatively called A, B, and C. The A-type viruses cause the most severe epidemics in humans, and only this type is further classified into sub-types on the basis of the two main surface proteins, one called Hemagglutinin (H), the other, Neuraminidase (N). There are 16 known H sub-types, and 9 known N sub-types, which means that at least 144 combinations, or strains, are possible. So far, only three (H1N1, H1N2, and H3N2) are in general circulation among people. In the mid 1900’s, scientists from the Rockefeller Foundation and other institutions conceived the ambitious goal of eradicating some infectious diseases entirely. They tried hard with Yellow Fever, spending millions of dollars over many years, and failed. They tried hard with Malaria, and failed. They tried again with Smallpox, and succeeded. Why? The differences between these three diseases are many and complex, but probably the most crucial one is that Smallpox resided neither in a reservoir host, nor in a vector such as a mosquito or tick. Its ecology was simple. It existed in humans and humans only, and was therefore much easier to eradicate. The campaign to eradicate Polio, which is still ongoing, begun in 1998 by WHO, is a realistic effort for the same reason: Polio isn’t zoonotic. Eradicating a zoonotic disease, whether a directly transmitted one like Ebola, or an insect-vectored one such as Yellow Fever is much more complicated, because to exterminate the pathogen you either have to exterminate the species in which it resides or interrupt transmission in some other way.

End

James Shepherd-Barron is an independent Disaster Management Consultant and has an honorary doctorate in International Public Health & Epidemiology.

[1] Herd immunity describes when the vaccination of a significant portion of the population provides a measure of protection for individuals who have not developed immunity. The greater the proportion of individuals who are resistant, the smaller the probability that a susceptible individual comes into contact with an infectious individual.

[2] DNA stands for ‘deoxyribonucleic acid’, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information. RNA stands for ‘ribonucleic acid’ and its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins.

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[i]              Suttle et al: Do viruses control the oceans?; Natural History Magazine, Vol.108, 1999