Do you believe in contagion?

I was at a workshop this last weekend.  One of the attendees had a cold and announced that anyone who believed in contagion might want to avoid hugging her.  And I thought, what????  Is that a joke?  Can she be serious?  Who could not “believe in contagion”?  It’s not like it’s a concept that originated in the last couple of centuries with the advent of science.  It’s been around a long time. Doubting that diseases are communicable would be like doubting gravity. But gravity is relatively new idea, a scientific explanation or description of what is going on when you drop a ball.   Doubting contagion itself would be more like doubting that a steel ball will fall to the ground when dropped. It wouldn’t simply be a pre-scientific idea, it would be a pre-civilisation idea. How could anyone of right mind doubt that contagion occurs?

That some diseases at least were communicated or were “catching” has been believed since the earliest times. The common people early convinced themselves of this fact, while the so-called scientists were wrangling over the spontaneous generation of disease or arguing whether or not disease represented a visitation of Providence. The Old Testament tells us of the fixed belief that the leper was dangerous to the touch. Hippocrates insisted that many diseases were communicated from person to person, and mentioned smallpox in the list. DeFoe, in his account of the plague in London, tells us of the well-defined and well-grounded belief that the disease could be communicated. Indeed tradition and history are full of accounts of plagues and epidemics from which the survivors, certain of the communicable nature of the pestilence, sought safety in flight.(1)

The idea that you can catch some diseases from other people is very, very old.  In the last 200 odd years this has been proven beyond any possibility of contradiction.  But, of course, there are those who will contradict no matter the evidence.  The science of contagion is wrapped up in the Germ Theory of Disease, which since the late 1800s has been firmly established as the mechanism by which diseases occur.  Little buggers – bacteria, viruses, fungi – are the cause of infection. When the little buggers are able to be passed easily enough from person to person the infection can be communicable.  And that’s contagion.  Those that doubt it or deny it pretty much have to deny all of germ theory along with it.  And denying germ theory is akin to denying gravity.

I’ve encountered germ theory denial in the person of Sherri Tenpenny, an ex doctor who has remade her career as an anti-vaccination loon.  She’s been quoted as saying.

 As contrary as it seems, germs are attracted to the diseased tissues; they are not the primary cause of it.

In fact, she’s written a whole article about it. What’s interesting about the Sherri Tenpenny story is not that she denies germ theory but why she does.  It’s obvious that she has a position that requires vaccines to all be bad, evil and dangerous.  That is the belief that dominates her life and career.  However, she once studied medicine and even practiced as a doctor for a while so she learned a bit of biology and epidemiology along the way.  Her anti-vaccine views were at odds with her scientific training so she had to choose one or the other. She chose to be anti-vaccine and seemingly found it easy to jettison science. An odd choice, but not all that unusual as it turns out.

Some of the groups that espouse Germ Theory Denial to one degree or another include: some HIV denialist, dairy cranks who believe in drinking milk raw, and a variety of alternative medicine modalities. While there are usually contrarians around who will reject just about any idea, Germ Theory Denialists seem to have an overarching belief of some kind.  There is something they  believe to be true which contradicts germ theory so they happily reject germ theory in favour of their pet ideology.

Personally I don’t “believe” in contagion.  I know enough about the history and science of disease to be able to make a rational assessment, and my assessment is that if someone close to me is sick with a communicable disease my chances of catching that disease go way up.

And yes, I now have a cold.