Wednesday, December 5, 2007

Science Behind the Seasonal Flu: Why Winter?

In October of 2007, Anice Lowen, Samira Mubareka, John Steel, and Peter Palese published a paper reporting that the reason we suffer influenza in the winter is “low relative humidity produced by indoor heating and cold temperatures … [which] favor influenza virus spread.”

Is it just me?  Or does that seem self-evident, obvious even?  I’m quite sure my grandmother told me that!

But it turns out that understanding how the flu is passed from host to host and why outbreaks happen in the winter has remained a mystery for many years.  This October I heard Dr. Marc Lipsitch, professor of Epidemiology from Harvard School of Public Health, talk about the great epidemic of 1918 and how many questions we still have about the virus.  Scientists and science writers love to talk about what we know rather than the unknown, the answers rather than the questions.  Although the great questions are obvious to the scientific community, they are often implicit and not part of the public dialogue.  And that’s why, when we learn something we thought we always knew, it can come as a surprise.

Isn’t that amazing:  that as much as we DO know about health and disease, there are still such basic things to learn about everyday phenomena like how the flu is spread? And we can be certain that, at some point in the not-too-far-distant future we’ll take this too for granted.  This little bit of scientific knowledge will be completely integrated into what we teach and learn about human health, biology and medicine as if we had always known it. 

But that’s a pity. Although it’s unlikely that anyone then will remember such a classic study, it’s worth trying.  Even then it will be important to remember:  that this knowledge was not always known; that this new theory was one of a variety of controversial, plausible explanations;  and that someone who cared needed to ask very specific questions, conduct experiments, and finally to collect evidence which supported or contradicted these alternative theories.  And we should remember that it all began with an idea in the imagination of the investigator and ended when a community of autonomous and highly independent thinkers have reproduced his results and challenged every aspect of his procedures and logic.

So why do we get the flu in the winter?  An article in the New York Times provided some interesting context for their scientific paper:
As long as flu has been recognized, people have asked, Why winter? The very name, “influenza,” is an Italian word that some historians proposed, originated in the mid-18th century as influenza di freddo or “influence of the cold.”
There was no shortage of hypotheses. Some said flu came in winter because people are indoors; and children are in school, crowded together, getting the flu and passing it on to their families.  Others proposed a diminished immune response because people make less vitamin D or melatonin when days are shorter. Others pointed to the direction of air currents in the upper atmosphere.
Although scientists have been speculating about this for centuries, it has been surprisingly difficult to study: first because it was unethical for scientists to expose people to the virus under controlled conditions; and second, until now, scientists did not have laboratory animals they could use to study the transmission of the human flu virus.

As is often the case, this science began with an accident and an observant, curious mind.  Dr. Palese, one of the investigators in the study, was reading a paper published in 1919, soon after the influenza epidemic.  From the article he learned that, in addition to 20 million human beings, the laboratory guinea pigs at Camp Cody in New Mexico apparently also succumbed to the virus.  Could these animals help him discover how the flu virus was actually transmitted? 

Is it possible that nobody else who read this article actually asked this question?  Apparently, yes.

In 2006, 87 years after the article was published, Dr. Palese acquired several of the guinea pigs and discovered that unlike laboratory mice, these animals can infect one another much the way people do.  Equipped with an animal model, he enlisted the help of three colleagues and began testing their hypothesis “that ambient air temperature and RH [relative humidity] impact the efficiency with which influenza virus is spread.” [1]

They constructed an apparatus to keep infected animals in isolated chambers under controlled conditions. Air was forced to flow through chambers with the infected animals into chambers with healthy animals, allowing only the temperature and humidity to vary. 

Gina Kolata reported in the Times:
They discovered that transmission was excellent at 41 degrees. It declined as the temperature rose until, by 86 degrees, the virus was not transmitted at all.  The virus was transmitted best at a low humidity, 20 percent, and not transmitted at all when the humidity reached 80 percent.
From this, they confirmed that:
Flu viruses spread through the air, unlike cold viruses, Dr. Palese said, which primarily spread by direct contact when people touch surfaces that had been touched by someone with a cold or shake hands with someone who is infected, for example.
But they also demonstrated that:
Flu viruses are more stable in cold air, and low humidity also helps the virus particles remain in the air. That is because the viruses float in the air in little respiratory droplets, Dr. Palese said. When the air is humid, those droplets pick up water, grow larger and fall to the ground.
The coverage in the is excellent with regard to what they learned about the flu virus, how hard it has to been to work on transmission specifically in the past, and how Dr. Palese discovered the animal model in the paper from 1919. 

The technical paper published in PloS Pathogens, on the other hand omitted this rich context, but nevertheless offered other interesting insights to the real work of the scientist which might be rewarding to the persistent, lay reader. In it I discovered, for example, that they had to rinse virus particles from the noses of the healthy guinea pigs to determine when and to what extent their inoculated neighbors infected them.  I also learned that they observed conventions that regulate how these animals are treated and that they were anesthetized before they were tested for infection. I could see that there were precautions – including the use of a ‘sentinel animal’ – that demonstrated that the researchers handling the animals were not inadvertently spreading the virus themselves, invalidating their careful experiment. And finally, underlying this simple experiment, the collaborative, rich web connecting many laboratories and technology providers is also quite apparent, all predicated on openness and trust.

This is all part of that texture, the tangible world of the researcher, which is transparent and obvious to other researchers but quite opaque to the lay reader and difficult to imagine.  How often do we refer to an ‘animal model’ without appreciating what it really is, how fortunate we are that we can study human disease in animals and how we can extend what we learn about these animals to ourselves?

And with regard to the really broad question I posed at the beginning of this essay:  what can this study teach us about the scientific community as a whole?  First, when scientists ask ‘why’ the flu is transmitted more readily in winter they really mean ‘how’. Although science can tell us a lot about how things work, it’s unable to help us understand what things mean.  I don’t want to suggest that these larger questions are not important to scientists – of course they are.  In fact, the human dimensions of health and illness, life and death motivate lots of scientists and doctors.  But you won’t find that in their own writing:  it is assumed.

And second, also rarely discussed, is the role of curiosity and relentless inquiry as the engine that drives science, not glory or riches (although they help too in some cases).  How many people would have read that paper and thought nothing of the guinea pigs death from human influenza in the great epidemic of 1918?   Lots of them, apparently!  Gina Kolata of the Times was right to include this crucial part of the story.  But she neglected to consider how Dr. Peter Palese might have been different, how he was able to see something new and ask an original question. 

Let's make the implicit, explicit, enumerating a list of what Dr. Palese had to believe, first of all, and then what he had to DO to make this science thing work: 

  1. He had to assume the mechanism of transmission was knowable and observable.
  2. He was optimistic about our ability as humans and his own capacity as a scientist to imagine new and untested ideas, to devise strategies to test their validity in the lab and then to use reason, extending their application to the real world.
  3. He had a precise question  -- he knew what he wanted to know.
  4. He was on the lookout for an animal model he could use to test the transmission of human flu.
  5. He was willing and able to do the test.
  6. He was committed to sharing his results with a community of peers, allowing them to decide if and to what extent they contribute to our understanding of the natural world.
Will we remember all this when we teach how the flu virus is transmitted ten years from now?  Is it enough to remember what we know about the flu?  Or is it just as important to recall how we know what we know, including some of the less obvious assumptions on this list?

If we succeed in communicating how we know what we know clearly embedded in specific examples of scientific research -- something real and true and human about the culture and practice of science – perhaps then we will become wiser, more mature as we puzzle over the limits of scientific knowledge, uncertainty, risk and controversies about global warming or stem cell research or mercury in tuna fish or the demise of the polar bear, for example. 

How can simple stories like this one help us answer another, larger question:  What is science, anyway?


Sources:

[1]  Influenza Virus Transmission Is Dependent on Relative Humidity and Temperature by Lowen AC, Mubareka S, Steel J, Palese P PLoS Pathogens Vol. 3, No. 10

[2] Study Shows Why the Flu Likes Winter by Gina Kolata, New York Times, 12/5/2007


Wednesday, October 31, 2007

The Challenge of Science and Civic Engagement

Many of the most complex and serious issues facing society today have significant technical and scientific dimensions: how to manage climate change, public health, loss of biodiversity, and dwindling natural resources, to name a few. These are not just technical or scientific issues, however. These are fundamentally social, political and economic problems with substantial ethical, moral and cultural dimensions.  Answers to these challenges require judgment, values and priorities in addition to empirical observation, experimental evidence, quantitative models and methods.

But no matter how you look at it, despite their utility in policy-making, the "hard sciences" are not always applied.  But why?  Although this is complicated and, for sure, there are many other factors, it's pretty safe to simply observe that, at the moment, scientists and their work are somewhat isolated from popular culture and the domain of policy decision-making.

Sunday, May 6, 2007

Cockburn Publishes Attack on Greenhouse Warming Theory

Alexander Cockburn published a story on Counterpunch today called "Is Global Warming a Sin?" attacking the theory of global warming. Initially the argument seemed somewhat personal and political but also cogent and founded on legitimate data and observations. However, after rereading it and looking for criticism -- especially of the arguments he raised that seemed original and missing from the mainstream debate -- cracks in his argument started to appear. And the closer I looked the more I realized that it's pretty sophisticated politically but really inadequate with respect to what I am beginning to expect of science journalism.

Despite the weaknesses of article, however, it is a great opportunity to understand the anatomy of a cultural and political attack on science itself.

Monday, April 30, 2007

Approval from Department of Commerce Required for Science Communications

The Union of Concerned Scientists has published a very simple review of new Department of Commerce policies regarding the communication of science to the public and has provided links to letters written in protest of these polices and the policy itself.

These are remarkable documents. On the surface, they appear to guarantee the "open dissemination of research results." However, upon closer examination it’s quite clear that scientists are actually required to seek approval from the Department of Commerce for any scientific communication.

Friday, April 13, 2007

Marine Protected Areas (MPA's) Not Growing Fast Enough

Erik Stokstad wrote in today’s Science NOW Daily News that we are not preserving marine biodiversity fast enough. According to Stokstad, Scientists meeting at the World Conservation Union (IUCN) believe we need to accelerate the creation of marine protected areas if we want to preserve marine biodiversity and move towards more sustainable modes of development.

At the World Summit on Sustainable Development in 2002, the signatories of the Convention on Biological Diversity (CBD) agreed that: 10% of the offshore regions controlled by individual countries (economic exclusive zones) and 20% of the world’s oceans would be protected by 2010. But Louisa Wood, a doctoral student at the University of British Columbia, has found that the total protected area would have to double every year for the next three years to meet that goal.

Wednesday, April 11, 2007

How Exxon Spent $15 Million to Create Confusion and Dissent in Global Warming Debate

The Union of Concerned Scientists has published an powerful and compelling report on exactly how Exxon spent $15 Million with dozens of shady organizations appearing to produce legitimate science and policy reports in order to discredit the real science behind global warming. It’s 60-some pages but really impressive in its attention to detail.

Most of the report is focused on the elaborate web of organizations, associations, think-tanks and consultancies Exxon has funded to create the impression that there is a large, heterogeneous group of informed scientists who disagree on the basic facts and theory of anthropogenic climate change.  They have documented a deliberate attempt to manufacture a controversy in science when, in fact, there is none.

Monday, April 9, 2007

Einstein on the Difference Between Science and Art

Apparently, Einstein wrote:
"Where the world ceases to be the stage for personal hopes and desires, where we, as free beings, behold it in wonder, to question and to contemplate, there we enter the realm of art and science. If we trace out what we behold and experience through the language of logic, we are doing science; if we show it in forms whose interrelationships are not accessible to our conscious thought but are intuitively recognized as meaningful, we are doing art. Common to both is the devotion to something beyond the personal, removed from the arbitrary."

Wednesday, March 7, 2007

TOS Education and Public Outreach Guide

The Oceanography Society has published a very useful guide to public outreach written specifically for scientists.  It agrees in principle with most of my own findings and might be a very valuable resource.

You can check out their site at http://www.tos.org and the guide is found here:  http://www.tos.org/epo_guide/index.html.

TOS Education and Public Outreach Guide

The Oceanography Society has published a very useful guide to public outreach written specifically for scientists.  It agrees in principle with most of my own findings and might be a very valuable resource.  Check out their site and their guide.

Brain Physiology of Love and Sex

Elizabeth Cohen posted this story on CNN about what cognitive scientists are learning about love.We exchanged a few emails on the subject so I figured I'd take one of them and post this blog entry.

Cohen wrote, “In a group of experiments, Dr. Lucy Brown, a professor in the department of neurology and neuroscience at the Albert Einstein College of Medicine in New York, and her colleagues did MRI brain scans on college students who were in the throes of new love.  While being scanned, the students looked at a photo of their beloved. The scientists found that the caudate area of the brain -- which is involved in cravings -- became very active. Another area that lit up: the ventral tegmental, which produces dopamine, a powerful neurotransmitter that affects pleasure and motivation."

Saturday, March 3, 2007

Some interesting websites on Science and Society

Report from the House of Lords Committee on Science and Technology.  An excellent assessment of the situation, analysis of root causes and recommendations for the future.  Published in 2000.

An interesting site by Bonnie Bucqueroux, who blogs about current threats and how we can respond at the personal and policy levels.  Great use of video and YouTube.

 There are dozens of Yahoo! Groups organized around energy issues.   Is it better to start a new group or join some other ones?  Or perhaps both?

Warning or Alarm

 NASA GISS Surface Temperature Analysis
The debate over Global Warming is a perfect example of how the integrity of scientific evidence and the credibility of science itself has been compromised in a highly divisive and partisan debate over policy.  The most visible proponents of each side present themselves as experts, present their own facts and ignore or undermine the facts of their adversaries.  Common ground based on accepted scientific evidence and practices disappears along with deliberative, public dialog.  Positions harden.  Real uncertainty and risk remain but disappear from view.  Subtleties are lost.  The public struggles to follow the debate and is mystified, confused.

Advocates on each side focus on short term benefits and political results.  Longer term education -- and a deeper public understanding of the issues -- is compromised.  When the public hears experts disagree they loose confidence in both sides.  Science and technology as a whole are diminished.

Debate of the the Nuclear Industry in the 1970's and 80's was another perfect case with similar consequences for science and technology.  The history of CFC damage to the ozone layer is another more recent example.  It is particularly tragic because now that we know that the alarm was real, that the intervention worked and that it was commercially very successful, the issue has passed from public view and science has missed the opportunity to regain lost ground.

Along the same lines many lessons have been learned from the disastrous limits to growth debate.  Yet in part because of the evidence collected in the process there is tremendous support for environmental protection, conservation and smaller family sizes throughout the industrialized world.  But the role played by scientists (not activists) in this global social movements and their contribution to what is now called sustainable development is still not universally acknowledged.

Lots of work has been done under the heading of Science, Technology and Society (STS) and the Public Understanding of Science as well.  One example of a comprehensive study is The House of Lords Select Committee on Science and Technology. Their |third report contains tremendous analysis of the tension between science, technology and society as well as what we can do about it.  (John Durant of the MIT Museum was somehow involved although I am unclear on his official role).

Warning or Alarm

The debate over global warming is a perfect example of how the integrity of scientific evidence and the credibility of science itself has been compromised in a highly divisive and partisan debate over policy.  The most visible proponents of each side present themselves as experts, present their own facts and ignore or undermine the facts of their adversaries.  Common ground based on accepted scientific evidence and practices disappears along with deliberative, public dialog.  Positions harden.  Real uncertainty and risk remain but disappear from view.  Subtleties are lost.  The public struggles to follow the debate and is mystified, confused.

Some interesting websites on Science and Society

Report from the House of Lords Committee on Science and Technology is an excellent assessment of the situation, analysis of root causes and recommendations for the future.  Published in 2000.

Strategies for Survival is aninteresting site by Bonnie Bucqueroux, who blogs about current threats and how we can respond at the personal and policy levels.  Great use of video and YouTube.There are dozens of Yahoo! Groups organized around energy issues.

Is it better to start a new group or join some other ones?  Or perhaps both?

Friday, March 2, 2007

The Challenge of Science and Civic Engagement

Many of the most complex and serious issues facing society today have significant technical and scientific dimensions: how to manage climate change, public health, loss of biodiversity, and dwindling natural resources, to name a few. These are not just technical or scientific issues, however.  These are fundamentally social, political and economic problems with substantial ethical, moral and cultural dimensions.  Answers to these challenges require judgment, values and priorities in addition to empirical observation, experimental evidence, quantitative models and methods.

Wednesday, February 14, 2007

Brain Physiology of Love and Sex

Elizabeth Cohen posted this story on CNN about what cognitive scientists are learning about love.

http://www.cnn.com/2007/HEALTH/02/14/love.science/

We exchanged a few emails on the subject so I figured I'd take one of them and post this blog entry.

Cohen wrote, “In a group of experiments, Dr. Lucy Brown, a professor in the department of neurology and neuroscience at the Albert Einstein College of Medicine in New York, and her colleagues did MRI brain scans on college students who were in the throes of new love.  While being scanned, the students looked at a photo of their beloved. The scientists found that the caudate area of the brain -- which is involved in cravings -- became very active. Another area that lit up: the ventral tegmental, which produces dopamine, a powerful neurotransmitter that affects pleasure and motivation."

"Dr. Brown said scientists believe that when you fall in love, the ventral tegmental floods the caudate with dopamine. The caudate then sends signals for more dopamine....  The more dopamine you get, the more of a high you feel" similar to the effect of cocaine on the nervous system.

The physiology of sex, on the other hand, appears to be quite different.  Cohen explained, “In studies when researchers showed erotic photos to people as they underwent brain scans, they found activity in the hypothalamus and amygdala areas of the brain. The hypothalamus controls drives like hunger and thirst and the amygdala handles arousal, among other things.  In the studies of people in love, 'we didn't find activity in either,' according to Dr. Fisher, an anthropologist and author of Why We Love -- the Nature and Chemistry of Romantic Love.

Let’s examine their findings in more detail and ask some questions.  First of all, how do we know the students they selected were actually in love?  And how do we know that looking at pictures of your beloved evokes the same response as love?  And finally, can we trust their conclusions?

This kind of questioning is a huge part of science.  Is the methodology valid?  Scientists are skeptical.  Unfortunately journalists are less so.  They rarely discuss questions on the methodology of the study or delve into the philosophical underpinnings of the conclusions and report on how scientists challenge one another.  Would that be boring?  Maybe.  But without that discussion, how do we know, really?  And I wonder if you could make it interesting....

In their search for a juicy story, science journalism is often guilty of exaggerating the claims or conclusions of the scientists themselves.  For example, in this case they might have concluded that brain region A was activated when the subject studied images of X while region B was activated when images Y were projected to the subject.  This deductive reasoning is solid:  if A then X and not Y.  If B then Y and not X.   It’s what makes reductionist science work.

But that’s not where it ends.  A good paper might cautiously extend limited conclusions like these beyond the scope of the experiment back to the considerably more complex “real world.”   The synthesis of these results with lots of other experiments on mind, brain AND body systems is actually inductive reasoning.  These results together with lots of other results might support (and do not contradict) a proposed model that accounts for the mechanisms of perception and other kinds of cognitive behavior.  We can’t say that the model is right.  We can only say that it has not been disproved yet.

Naturally, we would have to find and study the original paper to be sure of this.  But it does serve to illustrate this point:  reporters typically skip this intermediate step making it seem like the experiment is deductive reasoning about the real world.  It is not.

Implicit messages and omissions are another problem with scientific journalism.  Cohen wrote, “By studying MRI brain scans of people newly in love, scientists are learning a lot about the science of love: Why love is so powerful, and why being rejected is so horribly painful.”  To the romantic reader, lover of poetry, art or music perhaps, claims like this imply much more than is actually intended by the scientists themselves.  Knowledge of physiology tells us nothing about the subjective  experience of love at all and certainly can’t help us answer questions like “Why should we experience such feelings?”

Reasonable, well adjusted scientists are well aware that the model of the mechanism is interesting but totally distinct from the experience or the meaning of the phenomenon.  E. O. Wilson would suggest that’s exactly why science and literature and art and music are complimentary or even 'consilient' inductions insofar as they 'jump together' and reinforce one another.  It is assumed by scientists. Perhaps we should make it explicit for the rest of us as we ask, "but how do we know?"