Sunday, July 21, 2013

The Unseen

Late this afternoon, I found another tick. I’ve been plucking the little bastards off me for the past twenty-four hours, ever since I came in from the field. I write this not from the cozy comfort of my home in Cocoa, but from just outside Tomoka State Park. Located on the east coast of Florida and the site of my friend, Jon’s, archaeological field school, the park contains numerous sand and shell mounds among which Native Americans lived thousands of years ago. A professor at Eastern Kentucky, Jon is here to investigate the mounds’ histories and to train the next generation of archaeologists. Their first lesson in digging: wear plenty of bug repellent.
(Right: Jon Endonino, me, and Kevin Gidusko)

It’s summer in Florida, which means three things: heat, humidity, and a plethora of insects. The woods of Tomoka host the usual buggy assemblage - spiders, mosquitos, and ticks galore. And it seems no matter how much precaution I take, I return to the hotel crawling with hitchhikers. I really hate the little f#ckers.

It makes me wonder how the natives survived. How did they make it through endless summers while infested with these nasty creatures? They were obviously a hardier breed than us, what with our air conditioning and screened porches.

But at least I can see and feel the ticks, for it turns out our bodies play host to myriad unseen creatures. Let’s talk bacteria.

There are about two hundred different species of bacteria living on or within our bodies at any given moment. They colonize our skin, our orifices, and the different tracts of our bodies; those systems connected to the outer world via said orifices (think digestive and respiratory). In fact, bacteria outnumber our cells ten to one! And I thought a few ticks were bad.

Here are just a few of the bacteria that reside within various parts of your body: in your nose, corynebacteria mix and mingle; in your throat, Neisseria; your colon houses the enterics; and in your vagina (if you have one), reside the lactobacilli - the same genus used in cheese and yogurt (bet you'll never look at a cup of Yoplait the same again...).

This entire assemblage is known as the microbiota and it’s become a really hot topic among biologists, geneticists, and just about every nerdy “–ist” in science. It’s the new frontier in biological research and there are a particular set of science cowboys leading the charge.

The Human Microbiome Project (HMP), which is hosted by the National Institutes of Health, has set out to catalog the vast microbial communities each of us houses and to analyze the roles these critters play in our daily life and health. The HMP is taking a multipronged approach. It intends to not only identify and characterize the biome; it also hopes to sequence their genes in order to develop research strategies for investigating each and every species, all in hopes of better understanding the role the biome plays in maintaining health and preventing disease.

The majority of our bacteria are necessary for survival. As long as they stick to their assigned location and maintain their proper proportions, things tend to function normally. It’s when they go roaming or their numbers fluctuate dramatically that problems ensue.

For example, Escherichia coli (E. coli) is a type of bacteria that lives in your intestines. However, some types of E. coli, when ingested via contaminated food or water, can cause severe and sometimes deadly diarrhea. This is particularly troublesome in developing countries lacking proper sanitation (aka, a large chunk of the Third World). 

Streptococcus is a bacterium often found on the skin or in the throat and in most cases causes no problems. However, pregnant women who are vaginally or rectally colonized (yes, I just used the term “rectally colonized”) by group B streptococcus can pass it on to their newborns during delivery. This puts the babes at risk for developing meningitis, pneumonia, and septicemia. Sadly, these bacteria are one of the most common infectious causes of neonatal death.

On a positive note, studies of the microbiota can lead to fame and fortune. Just ask Barry Marshall and Robin Warren. In 2005, they earned a Nobel Prize for their discovery that peptic ulcers, previously attributed to stress and lifestyle, are actually caused by Helicobacter pylori, which commonly colonize the stomach, but wreak havoc within certain individuals. I hope the prize winners celebrated over a giant greasy pizza.

If there’s one takeaway from today’s blog, it’s that our bodies are so much more than meets the eye. They are teeming with life all their own; a world we cannot see but on which we depend. And for the most part, these bacteria are our friends.

But keep your fingers out of your orifices and your hands clean, for bacteria are fine when they stay put, but can raise hell if they go awanderin’.

To learn more about how our microbiota are affected by modern culture, pick up this great book by Rob Dunn. Very exciting!