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December 18, 2007

Movie plagues and pandemics and the real world

For Hollywood, the effort for any accuracy in the science of plagues and pandemics is only to make a more believable zombie or horror movie. I will list some of the movies related to the current number one box office movie "I am Legend". I will discuss some of the real science and statistics for pandemics and disease and the Lifeboat foundation's bioshield program.

The recent Will Smith movie "I am Legend"


is a remake of The Omega Man (1971) with Charlton Heston.



The Omega Man's synopsis:
Robert Neville who took an experimental vaccine, is the only survivor of an apocalyptic war waged with biological weapons. The plague caused by the war has killed everyone else except for a few hundred deformed, nocturnal people calling themselves "The Family". The plague has caused them to become sensitive to light, as well as homicidal. They are zombies with a bit of scientific explainations.


the Omega Man was based on the same book which was previously made into a movie The Last Man on Earth in 1964 with Vincent Price.



Dr. Robert Morgan (Vincent Price) is the only survivor of a devastating world-wide plague due to a mysterious immunity he acquired to the bacterium while working in Central America years ago. He is all alone now...or so it seems. As night falls, plague victims begin to leave their graves


Popular Mechanics discusses the science of viruses as it relates to the movie "I am Legend"

What happens when you manipulate the measles vaccine into a retrovirus, then apply it to cancer patients in a clinical trial? In Legend, you cure cancer. At first. Then, the patients begin to get sick. Most of them bleed out, but those who don't become hairless, transparent, vampire-like mutants who are allergic to sunlight and crave blood. They spread the disease by biting others. When the virus mutates and goes airborne, it spreads rapidly, killing everyone on Earth except for those who are immune—and slowly, even they are picked off by the vampires, until only one man is left.

Dr. W. Ian Lipkin, one of the world's top virologists and director of the Laboratory for Immunopathogenesis and Infectious Diseases at Columbia University Medical Center, says the scenario presented in the movie doesn't seem plausible at all. “It sounds pretty far-fetched,” he says. “Viruses don't mutate and become airborne. They typically fall into a couple of different categories—respiratory, STDs and vector-borne like insects, ticks and mosquitoes. They don't change from tick-borne to pneumonic. They just don't do that.”


So the Charlton Heston "The Omega Man" movie plot use of devasting biological warfare is somewhat more plausible. If some military research group were to purposefully create a pneumonic version of a deadly microbe. One factor is that such a research group would certainly want to be control the spread of their biological weapon and/or provide immunity to their side.

I am on the advisory board of the Lifeboat foundation and one of their programs is a Bioshield to help reduce and limit the risks of pandemics

Influenz pandemics occur fairly regularly every few decades. The worst recent influenza pandemic was the Spanish flu (at the end of WW1) which killed 40 million.

There is a pandemic severity index, which measures how bad a Pandemic is.


CDC Pandemic Severity Index
Category Case Fatality ratio (CFR) example(s)
1 less than 0.1% seasonal flu
2 0.1% to 0.5% Asian Flu and Hong Kong Flu
3 0.5% to 1%
4 1% to 2%
5 2% or higher Spanish flu


The difference between the distribution of those who died in average flu years versus the Spanish flu is that the Spanish flu was somewhat deadlier for all ages but especially a lot more deadly for 10-45 year olds (especially those round 20-25 as a lot of soldiers were in ideal areas, the trenches, for catching and dieing from the disease). Normally flu primarily kills infants and the elderly.

HIV/AIDS has killed 25 million in its first 25 years.

Typically, in a year's normal two flu seasons (one per hemisphere) there are between three and five million cases of severe illness and up to 500,000 deaths worldwide, which by some definitions is a yearly influenza epidemic. Although the incidence of influenza can vary widely between years, approximately 36,000 deaths and more than 200,000 hospitalizations are directly associated with influenza every year in America.

Historically the worst plagues killed up to 50% of a population. (bubonic plague)

In modern times, if a disease becomes infectious and the onset of symptoms happens quickly it allows medical professionals to quickly quarantine vectors and prevent them from carrying the pathogen elsewhere. This means if you are infected and get very sick or die quickly then it is easier for public health measures to be taken to stop the disease from spreading.

Limiting and controlling transmission is one of the most important steps for disease control. Real world diseases have to spread and get through the biological defenses of the host. This can be modelled with transmission risks and rates. Those factors can be reduced by having fewer gatherings of large numbers of people (like sports stadiums) and having everyone wash hands with soap more frequently.

We can get a far better handle on many infectious diseases by finding the infection reservoir sources of the disease. If we know that mosquitos are hosts for Malaria then we can take steps to reduce the amount of Mosquitos with Malaria and reduce the exposure of people to Mosquitos with Malaria.

Improvements in science also provide more tools to fight real world diseases. Using gene sequencing, understanding of proteins, RNA interference, RNA activation etc... we can understand and potentially disrupt the molecular processes of a disease or increase human resistance to diseases.

Similar movies:
28 days later


FURTHER READING
Annual deaths from infectious diseases Up to one third of the 55 million annual deaths have been from infectious diseases.

Alfin also has article with his take on "I am Legend" and real world plague threats

2 comments:

Anonymous said...

I have always found the poor epidemiology of zombie movies like '28 days' and 'Dawn of the Dead quite irritating. In order for a zombie plague to spread and become pandemic from a modest initial start each zombie has to on average 'convert' at least one human before being destroyed. However, stupid zombies that do not use technology can be destroyed in vast numbers. One armed individual could simply walk around with a large quantity of ammunition killing hundreds of the slow-moving zombies from 'Night of the Living Dead,' and even the fast-moving zombies of the other films could be dealt with en masse by groups of armed citizens led by police or military from fortified positions (even with zombies running at marathon speed, most regions will have time to prepare).

The only quasi-plausible zombie plagues are those that initially and subsequently infect people through means other than bites from human zombies. In 'Shaun of the Dead' the plague spread like an influenza before converting victims into zombies, ensuring that most of the population was converted to start, such that the kill ratio of the survivors didn't immediately destroy the plague (which was nevertheless defeated in a matter of days).

A zombie plague that could be carried by zombie rats and birds (as in the recent 'Resident Evil' film) would be tremendously more apocalyptic still.

Anonymous said...

"quasi-plausible zombie plagues"
That is, after suspending our disbelief about zombiedom, where the subsequent scenario is internally coherent.