. . . Reprinted with permission from
      DES MOINES REGISTER
      (Des Moines, Iowa)
      Aug. 16, 1996, pp. 1T+

MICROBE ALERT: YOU'RE HOST TO BILLIONS OF THEM
by Rick Ansorge
Colorado Springs Gazette Telegraph

More of These Organisms Inhabit You Than Human Beings Inhabit the Earth. If You Were Freeze-Dried, 10 Percent of Your Body Weight Wouldn't Be You.

     A hideous creature with a cucumber-shaped body, eight stubby legs and a gaping mouth snuggles peacefully in its home sweet home--your face.

     It's the microscopic face mite, and it lives on nearly 100 percent of human faces worldwide. It's found in the skin's oil-producing glands, sometimes even in earwax.

     But its favorite haunts are hair follicles, especially the ones at the end of the hairs that grow in your nose.

     But don't get out the tweezers just yet. Unlike the micro-organisms that command most people's attention, the face mite is a harmless beast, at least to humans. It sometimes gives dogs the mange.

     About the worst it can do to people is produce an uncontrollable urge to scratch their faces when they read stories like this.

     "I don't think people realize how much microbial life there is," says James Mattoon, biology professor and director of the Biotechnology Center at the University of Colorado, Colorado Springs.

     More of these organisms inhabit you than human beings inhabit the Earth. If you were freeze-dried, 10 percent of your body weight wouldn't be you.

     The process begins the moment you're born.

     "The skin becomes contaminated during passage through the birth canal," write the authors of "The Microbial World," a college-level biology textbook. "The mucous membranes may be sterile at birth but become contaminated within hours."

     In breast-fed infants, the intestinal tract is filled with a bacterium that disappears after weaning, but at any age, the human digestive tract is a bacterial metropolis.

     "When you get to the large intestine, the population grows astronomically," Mattoon says. "The numbers in human feces exceed one billion cells per gram."

     These intestinal "flora," as scientists call them, not only help digest food. "Some of them actually produce certain B vitamins," Mattoon says.

     Another bacterium, Lactobacillus, keeps women from being plagued by yeast infections. It protects the vagina by being so numerous that it crowds out more harmful organisms.

     Other hotbeds of microbial activity include the body's 2 million sweat glands. Also the mouth, nose and throat, which are home to many exotic species, including the gelatinous mouth amoeba.

     Some areas of the body, however, are practically germ free. These include the heart, liver and brain, which the body isolates from such contamination, and the stomach, where strong acids turn microbes to mush. The eyes are protected by an anti-bacterial agent secreted by the tear ducts.

     But in the areas where microbes thrive, it doesn't take much to upset the delicate balance. Diseases affecting the immune system can disrupt this balance by destroying useful bacteria. So can certain drugs, especially steroids and antibiotics.

     In the large intestine, this can produce serious digestive upsets. Some doctors recommend taking Lactobacillus acidophilus supplements to correct the imbalance; others say it's of questionable value.

     In women, the chemical slaughter of useful organisms can have long-lasting consequences. "If a woman takes antibiotics and it kills off those useful organisms," Mattoon says, "some of the others that are just sitting around in there might start to cause problems, like yeast infections."

     Under normal circumstances, good flora aren't parasitic. "They're either symbiotic organisms, or they're just there," Mattoon says.

     When the balance is disrupted, however, even benign bugs can turn bad, invading tissues they usually ignore. This shows how a symbiotic relationship can shift from mutualism to parasitism and back again, write the authors of "The Microbial World." Humankind remained unaware of the microbial world until the 1600s, when Dutch lens grinder Anton von Leeuwenhoek peered through his homemade microscope and saw the first protozoan, probably a Giardia.

     Since then, scientific opinion has evolved past the point of view that micro-organisms are enemies that must be destroyed.

     The new field of molecular evolution stresses coexistence. Noting that bacteria are earth's oldest living creatures, predating humans by some 3.5 billion years, today's scientists believe microbes and humans evolved together.

     At first, the relationship was hostile, but over time the human body tamed invading bacteria as effectively now as early cave people tamed wild dogs. Eventually, humans and microbes became so interdependent they fused on a cellular level.