Saturday, September 17, 2011

CONTAGION: Science fact or fiction?

Whenever Hollywood educates the public about viruses, the story often ends with a movie star or two turning into flesh-eating zombies and a virus ultimately killing everything it touches.  The movie "Outbreak" is one of few that maintained a shred of credibility. Below I discuss the movie Contagion, a new pandemic thriller that actually gets a lot of the science right, but does contain a few unlikely details.

SPOILER ALERT!!!  Watch the movie before reading further!

Scientists have touted the movie as a realistic depiction of disease transmission—no movie stars turn into flesh-eating zombies, and the previously unknown disease does not kill every person it encounters. But despite some impressively realistic details, there are still parts of the movie that would be pretty unlikely in real life.

Jude Law's character, a nefarious blogger, roams the post-apocalyptic streets of San FranciscoMimosveta, FlickrJude Law lost in a garbage bag?

MOVIE SUMMARY:

  Gwyneth Paltrow is an executive that falls ill on a company trip to Hong Kong. She infects a few unfortunate people, and the world is overrun with the disease - a virus called MEV-1 that contains bat and pig DNA. Chaos ensues shortly after, several actors either die tragically or become heros, and the world is saved in the end by intrepid scientists who whip up a vaccine in less than six months!

UNLIKELY - An exective is the first to fall ill with a virus containing BAT and PIG DNA?

In reality, a super infectious virus would mull around local populations. A factory worker at the pig farm, for example, would be a more likely patient zero than a business executive.

TRUTH - The virus (MEV-1 or Nipah virus) is a real pathogen.

The Nipah virus is real. Infection causes respiratory symptoms, encephalitis, and seizures. Nipah has a reservoir in bats and has killed hundreds in Malaysia and Bangaldesh. BUT, it usually doesn’t transmit between humans well.  However this could change and that's why real scientists are currently trying to develop a real vaccine for Nipah.

LIKELY - Virulence of the Pathogen

The movie virus is actually rather restrained, killing only one out of every four of the people it infects and spreading to two people for every one who gets the disease. This is actually a very realistic transmission profile. The real Nipah virus kills 45 to 90 percent of its victims.

LIKELY....sorta - The path of viral transmission

At the end, the movie explains where the virus came from. A factory is built on a bats' habitat, a bat flies into a pig farm, and a fruit drops from its mouth into food eaten by pigs. One of pigs is slaughtered and prepared in a Hong Kong restaurant where Paltrow shakes hands with the chef—who presumably has some of the new virus on his hands—and TADA!! Global pandemic.

This pathway from animals to humans is very realistic. Close interaction between human and animal have caused real pandemics (Bird flu turned into the 1918 Spanish flu and killed 1% of the global population). But the fact that it spread from the chef to Paltrow with no prior history of infecting ANYONE else is highly unlikely.  In reality, the disease would mostly live in animals and be transmitted from animals to humans for a while, gradually becoming more easily transmitted from human to human.
But rapid transmission is a reality for RNA viruses, which don’t have proofreading abilities used by DNA viruses. As a result, RNA viruses mutate very quickly and become much more infectious. For example, the annual outbreaks of Nipah in Bangladesh are often completely different strains (This is of course only true to those that believe in evolution!).

UNLIKELY - Scientists create a vaccine in 4 months.

The virus in the movie is completely unknown on day zero. But scientists are able to grow it in just 12 days, and have a vaccine ready in 4 months. Scientists work hard, but that’s a stretch to say the least! For example, scientists have been working on Ebola for decades and there is still no vaccine. A virus similar to Nipah has been studied for more than 40 years, yet scientists still haven’t found a vaccine.

Outside of science talk, I loved the movie...I think I'll let my cousin Mark do the actual movie review!

Wednesday, August 31, 2011

Bacterial Mind Control?

As most of my family and friends know by now, I'm all about promoting the understanding of microbes, or as I call them...."my children".

Several studies have linked the health of bacteria in our guts to our own health.  Even more interesting is that science is quickly showing how bacteria control how we feel. In a way, our brains are slaves to our intestinal bacteria. I recently emailed about the study that linked brain inflammation and depression to bad bacteria in our gut.  But not all bacteria are bad.  In fact, the vast majority of gut bacteria could careless that they are living in our body instead of a turd in a toilet, and some of these non-evil bacteria are also controlling us in a good way!

A very convincing study in mice has just shown that probiotics can relieve inflammation, depression and anxiety. The question remains if they are releasing chemicals that help us directly, or whether they are competing against (and thereby diluting) the harmful effects of the bad bacteria. Either way, this is a reminder that the majority of bacteria want to live with us and not kill us. 

Antibiotics cannot select out bad bacteria. Instead, they destroy all bacteria in your body.  This is why antibiotic resistance is such a problem.  If one bad bacterium evolves to resist the drug, it no longer has any competition in your gut.  It OWNS your gut. So the next time you feel anxious or just finished a cycle of antibiotics, think about the health of your bacteria and whether they can use a probiotic yogurt or two.

Brenda also just took notice of a new technique to treat cancer. Viruses! http://www.cbc.ca/news/health/story/2011/08/31/cancer-virus-intravenous-study.html
As you can tell from the comments below the article, most people get their science information from movies and would rather die of cancer then get infected and turn into a carnivorous nocturnal zombie.

The take home message here is that viruses and bacteria have evolved with us and as a result we depend on each other (This of course is only true to those of you that believe in evolution!).
If we want to live healthier and longer lives, we should focus our efforts on how to live with bacteria and not on how to eradicate them.

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