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May 2, 2004
Outside Magazine

Outside magazine, July 1999

Hey Buddy, Is That a Virulent Pack of Angry Clostridium perfringens in Your Sierra Cup?
The woods were alive with disease-causing bacteria, fungi, viruses, and protozoa. Then Professor Charles Peter Gerba, aka Dr. Germ, the sultan of slime, antimicrobial soap slinger, showed up in camp with hate in his eyes.

By Andrew Tilin

It's high noon on a hot, scentless day in the Santa Catalina mountains, and the southern Arizona sun is glaring down on the withering manzanitas and mesquites. Spiny limbs of saguaro and cholla cactus run alongside a faint trail like God's own barbed wire fencing. Over a sharp rise in this landscape of rocky and lusterless soil steps Dr. Charles Peter Gerba, walking point at the head of a small column of hikers. Shoulders straining against the straps of a borrowed Boy Scout pack, Gerba stops and pulls a map out of a shirt pocket. "I'll tell you," he says, shooting a glance at the granite walls ahead. "If man's been up there, then they're up there too." He puts the map away, tugs the brim of his ball cap lower, and lurches onward, undeterred, leaving the rest of his squad to contemplate the looming specter of a close encounter.

Before this eight-person expedition set out, Gerba had been frank about the risks they would be facing. They would confront remorseless, predatory wildlife; faceless, invisible creatures that attack without mercy. Luckily, Gerba had been studying these beasts for decades, and better than almost any man alive he knew their insidious ways, and also their weaknesses. Still, these organisms, as he dispassionately calls them—for Gerba is a man of science as well as a warrior—were going to hopelessly outnumber this small scouting party.

Another hundred yards and he comes to another abrupt halt. Everyone stops dead in their tracks. Gerba squirms out of his pack and rifles through it, emptying its contents onto the trail: glass vials, heavy-duty cotton swabs, disinfectant gels, antibacterial sponges, water purifier, multicolored pens, and notepads. He finally digs out what he's after—bottled water. "You know, I should've brought beer," he says after breaking the seal and taking a long swig. "You never hear of an outbreak among people drinking beer. Parasites swimming in beer will die within 24 hours. Mark my words."

Only a fool would do otherwise. Chuck Gerba, or simply Dr. Germ, is an internationally renowned environmental microbiologist who sees the world through distinctly non-rose-colored glasses (actually, he sees it through bifocals). The 53-year-old University of Arizona professor is an expert on the infinitesimal monsters residing in our water, food, and homes. He made his reputation a quarter of a century ago by opening scientists' eyes to the problem of dangerous microorganisms migrating into groundwater. Then his lab created the test for detecting the parasite cryptosporidium in water, changing the way American municipalities treat tap water. Backpackers have Gerba to thank for developing the tests that the Environmental Protection Agency relies on to certify water purifiers.

But the public knows him best for his crusading on behalf of household hygiene. Overstuffed shirt pockets, a chronically off-center belt buckle, and nasal voice notwithstanding, Gerba is as masterful in front of a television camera as he is behind a microscope. In appearances on Good Morning America, Today, and Dateline, he despairs of the state of cleanliness in the American home. He gleefully points out that hepatitis A can survive a cycle in the washing machine, and he shocks viewers with his assertion that, typically, bathrooms are cleaner than kitchens. The thrust of his message is that, as a nation, we need to "reprioritize our sanitation strategies"—to mobilize ourselves against the germs lurking in our homes and start disinfecting our countertops, our sponges, our phones.

Not surprisingly, some of Gerba's peers snicker at his fussy lobbying, dismissing what he says as little more than exacting janitorial advice. But Gerba is too enthusiastic to care. "He'll crack up his stiffest colleagues talking about contamination in the bathroom," says Joan Rose, a microbiology professor at the University of South Florida in St. Petersburg. "Then they'll realize that Chuck's focusing on public health and that the science is serious." Indeed, despite decades of progress, microbes are the number-three killer in the United States, and in recent years there has been fresh reason to be alarmed, given the rise of antibiotic-resistant infectious agents and other counterattacks from a trillions-strong army.

Still, apart from his contributions in the field of portable water-purification, Gerba has generally left the outdoor-adventure crowd to frolic in the wilderness untroubled by thoughts of lecherous organisms and teeming, invisible filth—until today. This expedition represents Dr. Germ's first real foray into a realm untouched by Lysol and bleach. "The risks in camping haven't really been properly recognized," he says to me in a low voice as he pauses yet again, taking off his hat to mop his glistening pate. He spots his wife, Peggy, an arachnologist, trudging along behind. Farther down the trail are Duncan Veal, a 40-year-old visiting Australian microbiologist; Veal's wife, Christine, and their two little girls, Clare, 12, and Jenny, eight; and Caroline Höglund, a 27-year-old doctoral candidate in microbiology from Sweden. Gerba hikes his jeans up under a tetherball gut. "For this group, the risks could be greater than anyone might think."

It's nearly dusk by the time we pitch our tents in the shadows of Romero Canyon, and a call goes out to replenish the water supply. Our group locates what the guidebook describes as "large, deep pools that are excellent for swimming." Gerba stands over the biggest hole—only about the size of a tiny kiddie pool this time of year—and sighs. There's a dark, furry scum on the bottom. "At least we're safe from neurotoxins," he tells his companions in an unconvincing effort to be cheerful. "You usually find those only where the algae content is heavy. Drink water with a lot of blue-green algae and your heart can stop. Kills cows all the time. Dogs die." He pulls out a new water purifier and begins reading the instructions and playing with the rubbery hoses. "We'll be fine," he says reassuringly, looking at the anxious faces around him. "What are you all so worried about?"


Ever since seventeenth-century Dutch naturalist Antonie van Leeuwenhoek described the tiny "animalcules" he'd spied in rainwater using a crude microscope, mankind has struggled to come to terms with the full potency of the single-cell kingdom. Viruses, bacteria, protozoa, fungi—they're all microbes, and they exist in far greater numbers than do plants and animals. In a single gram of garden soil you might find 10,000 microbial species, and more than a million viruses can lurk in a teaspoon of seawater.

A microbe's sole purpose is to live, and it is robustly equipped to do so, sucking in nutrients through its entire body surface and spawning with itself. Although most microbes do God's work, providing us with oxygen, devouring oil spills, helping create chocolate and sourdough bread, there are plenty of bad eggs, called pathogens. Take Clostridium perfringens, the microscopic studhorse that causes gangrene: It clones itself every nine minutes. Giardia and cryptosporidium protozoans inhabit an estimated 97 percent of America's surface waters, which is why Gerba holds that there is virtually no river or lake clean enough to drink from without using some kind of water filter or purification system.

It turns out that the nature we all like to think of as untainted actually hasn't been so for hundreds of millions of years. "As long as there have been animals, there has been no such thing as pristine wilderness," Gerba says. "You can safely touch rocks and branches, but only if some creature hasn't just soiled them with enteric bacteria. There's always that risk." Enteric bacteria flourish in the solid waste that all people and animals leave behind wherever they go. And the spread of germs only becomes that much more prolific as our expanding population competes with animals for wilderness.

Say a wandering cow releases a few billion E. coli 0157:H7 organisms into a creek. Miles downstream, you go for a swim, and along with a mouthful of water you inadvertently swallow several of the little buggers—the same bacteria that ruined Labor Day weekend for a lot of people two years back. They get into your small and then large intestine, where they start doubling their numbers every 20 minutes. In ten hours millions of organisms are releasing toxins that kill off two-inch sections of intestinal lining at a clip. After a few days you're feeling wrong. Soon you're suffering from cramps and dehydration. If you can't get medical attention and antibiotics, the bacteria may cause shock, organ failure, brain malfunction, and finally, charitably, death. Richard Preston himself couldn't dream up a more charismatic villain.

It's Chuck Gerba's job to help us steer clear of such hot zones. A couple of days before our camping trip, Gerba is bustling around a windowless laboratory in Tucson. "Jaime, are you finished cleaning all of this?" Gerba calls out, nudging a small tub beneath a sign that reads water is being tested for all sorts of terribleness. Jaime, a research assistant, pulls his head out of a refrigerator containing vials of dreaded enteric pathogens and gives his boss a nod.

Gerba has 2,400 square feet of lab space at his command—16 rooms filled with centrifuges, $14,000 ultraviolet microscopes, and a small army of graduate students wearing rubber gloves and protective coats—but it's in the cramped confines of Room 415 that the fate of most commercial water purifiers is decided. On the wall above the sink hang the cannibalized remains of 23 systems that have come under the lab's scrutiny. "Most of them don't kill off enough organisms," says Gerba, fingering a Russian-made unit that resembles an oversize straw. "With some of them I can't even tell which way is up."

His opinions are not taken lightly. Some 15 years ago, the EPA asked Gerba and three other scientists to establish procedures for testing portable water purifiers. Unlike simple filters, which trap bacteria (such as E. coli) and parasites (such as cryptosporidium) but can't stop tiny viruses (hepatitis A, for example), purifiers combine a filter maze with a chemical oxidant that renders most viruses harmless.

The EPA will only grant its stamp of approval, in the form of a registration number on the packaging, to microbial purifiers, meaning devices that let through no more than 0.0001 percent of bacteria, 0.1 percent of parasites, and 0.01 percent of the original concentration of waterborne viruses. Plenty of folks see this as overkill, maintaining that by themselves filters offer ample protection in the emptiest stretches of U.S. backcountry. You can guess what Gerba thinks.

"Some people argue that you don't have to worry about using a purifier in the backcountry, but does anyone really know what's going on upstream?" he asks. Lost in thought, he taps the business end of the Russian-made gizmo against his lower lip and then abruptly stops, realizing what he's doing. He looks at the thing and quickly wipes his mouth on his sleeve. "You know, a lot of people shrug off getting sick as an act of God. I just don't believe that. There's always a reason for someone catching a bug."


Summit day. Romero Canyon cradles a crisp desert morning, and Gerba's team is moving around camp stiffly after yesterday's epic 2.8-mile trek from the parking lot. Preparations are under way to make a hearty breakfast, but several campers can't wait and begin passing around a plastic bag of raisins. Gerba, who's pulling up his brown, ribbed socks, spots the noshing in progress and immediately intervenes. "Is this a communal bag?" he demands, snatching the evidence and holding it at arm's length. "When it comes to touching food, as few hands as possible should be involved. These two already have gastroenteritis," he says, pointing at Christine and Caroline. "Now everybody's going to have it." Among other things, illness in the ranks could jeopardize the planned assault on Romero Pass, 2,300 feet above our campsite by way of a steep, snaking trail.

"A little bit of bacteria is good for the stomach," jokes Caroline.

Gerba's not mollified. "I'm not letting you make a meal."

Such zealous devotion to one's cause might be seen as at best nerdy, at worst fanatical. For Gerba, it's personal. The oldest of six children born to a technical writer and a housewife in Blue Island, a working-class suburb southeast of Chicago, Gerba contracted polio in 1952, at the age of seven. The virus paralyzed his right side temporarily, keeping him out of school for two years. (His right hand, which he writes with, still doesn't close completely.) The Gerbas moved to Phoenix when Chuck was nine, and the kid his friends called Chuckles spent a lot of time building volcanoes and blowing up toys and other household items. He desperately wanted a chemistry set for Christmas, but when his mother mistakenly gave him a microscope, Chuck shifted his energies to ogling slides of hair and spit and whatnot. And though it might not seem obvious today, the teenage Gerba actually went on to become an Eagle Scout.

As a student at Arizona State in Tempe, Gerba dove headlong into his pursuit of microbiology after reading Paul De Kruif's 1926Microbe Hunters, a popular account of the achievements of such germ-seeking pioneers as Louis Pasteur. He earned his Ph.D. in microbiology from Florida's University of Miami in 1972, not long after marrying Peggy, a lab technician from Phoenix. The first of two sons, Peter Escherichia (after the E in E. coli) was born three years later. In 1981, Gerba moved his family back to the wide-open southwest, signing on as a lecturer at the University of Arizona in Tucson. He was made a full professor in 1983.

It's a career that, over the years, has perhaps become too all-consuming. This morning, for instance, after Duncan—the only other fully accredited microbiologist on the trip—is permitted to start cooking a pancake breakfast for everyone, Gerba decides to hold an impromptu hand-washing clinic. Everyone gathers around the professor, who's standing in front of his tent sorting through a collection of liquid soaps and gels. "Most people don't scrub enough," he says. "But you need to remove bacteria, stuff that gets on your fingers and palms, like salmonella."

I'm nominated to be a test subject. He squirts some goopy soap into my hands and tells me to rub my palms together and work the suds between my fingers. As I wash with the vigor of a surgeon scrubbing in for a tricky bypass, Gerba adds that I should keep my hands pointed down so bacteria can't creep up my wrists. "You really ought to rinse your hands with running water for at least 20 seconds to get everything off," he says, rinsing me off for just a few seconds with one of the precious few remaining bottles of water that we carried in. Looking first at the nearly empty bottle and then the rest of the group, he adds: "For camping, maybe it's best to wash your hands in a stream and then use one of these no-rinse antimicrobial gels."

Flapjacks are served. Gerba lays out a cafeteria's worth of seemingly spotless plastic spoons, forks, and knives—all of them "fomites," in Gerba's view. A fomite is any inanimate object that can carry germs and lead to cross-contamination: A hiking-boot lace, camera, sleeping pad, kitchen utensil, even your beloved coffee mug can become a single-cell zoo.

(In 1997 Gerba and two colleagues published a study on coffee cups in the journal Dairy, Food and Environmental Sanitation. They collected "clean" mugs from ten coffee nooks around the University of Arizona campus and tested them for live pathogens. Of the cups with that familiar dark ring inside, 75 percent were home to pathogens such as Klebsiella pneumoniae and Pseudomonas cepacia, which can cause colds. A few mugs in the study even contained E. coli. "The bacterial coliforms growing in coffee cups don't usually cause illness in healthy individuals," Gerba explains. Most of us are perfectly capable of producing enough antibodies to ward off such germ invasions; the vulnerable ones tend to be very young, very old, or very sick.)

The sun is rising fast, and breakfast is long over by the time the hikers are rubbing in sunscreen, ready to hit the trail. Gerba grabs a water bottle that he'll share with no one and gives the campground a quick scan. That's when he spies the dirty dishes. "It's better to wash these now," he announces. There are no volunteers, probably because we all remember last night's Gerba-supervised dish-washing session, an elaborate operation involving conventional cleaning, a rinse cycle using very hot water, and a final dousing with water containing iodine, lest "microbes persist." Gerba fishes around in his pack until he finds the dishwashing soap. "Do you want a bigger battle later?" he asks. "Do you want to be gut-crunching in the woods?"


We're barely a half-hour into the nine-mile round-trip to Romero Pass when the group starts to string out. Gerba is lagging, and I'm keeping him company as we bring up the rear. "In the '70s, Peggy and I were doing a lot of camping," he says, pausing to tie a shoe at the first of an interminable series of dusty switchbacks. "I was a postdoc, just becoming acutely aware of waterborne dangers, just starting to boil my drinking water. Unfortunately, I was also getting too busy with work." This is his first backpacking trip in 15 years, he tells me.

When we catch up to the others, gathered in a dispirited clump in the middle of the frying-pan trail, Duncan is crouched with his head down, Christine is fanning the girls, and Caroline is shifting her weight from leg to leg. Gerba veers urgently off the track, picking his way around prickly foliage toward a lone alligator juniper 50 yards distant, and plops down on a granite platform beneath the tree. The group follows, crowding into the meager shade and pulling at damp, sticky shirts.

We're in trouble. Sweating is, microbially speaking, best avoided. Billions of microorganisms live on our skin, and while some enjoy a friendly symbiosis with man, others are ill-mannered tenants. When you perspire, bacteria dine on the endemic salts and acids and then give off what we fondly know as BO. Offensive, yes, but the real dangers are that sweat can promote fungal growth on your feet, clog your glands until you suffer from heat prostration, and attract dirt that acts like sandpaper, scoring your skin and inviting other loutish pathogens that can cause staph infections.

Pushing such unhappy thoughts out of mind, we dine on Star-Kist burritos and turkey jerky. Afterward, Gerba gallantly suggests that the rest of us should not wait for him; we still have a shot at the pass, but he doesn't think he's going to make it. So we forge ahead. Another mile up the rutted hillside we crest a plateau. It's not Romero Pass, but there is a spectacular view of 7,952-foot Cathedral Rock to the south, the Tucson suburb of Oro Valley, and Tucson itself, to the west. It'll do. Duncan turns around to see if Gerba is coming. No sign.

"Chuck really looked exhausted," he says. Duncan came to the States specifically to study with Gerba and says he's learned quite a lot about removing environmental pathogens from water. "You know, there usually isn't much reverence among microbiologists—we all just go about our work. But with Chuck, it's hard not to think of him as renowned, almost a father figure."

We hoof it down and collect the professor, still recovering in the shade. Back at camp, Peggy and Duncan cook dinner, and soon the only sounds we hear are mesquite popping in the campfire and the slurping of ramen.

Suddenly Gerba springs up, scurries off, and returns with a folded bundle of plastic. With a snap of the wrist he unfurls what vaguely resembles some cheap beach toy, and goes to work blowing it up. The lettering on the side slowly comes into legibility: inflate-a-potty. Clare and Jenny pile onto the slippery throne, giggling and bouncing up and down.

The girls abandon it when Peggy pulls out a bag of marshmallows for roasting. Gerba plops down and begins to share his evaluation of the Inflate-A-Potty. Unfortunately, his review is not positive. "It's too narrow a hole," he announces. "American toilets have the greatest width of any that I've ever measured. You ever measure a toilet seat?" he asks.

"It's just that your toilets are filled so full with water," Caroline replies politely. "If you have to puke, it splashes right out at you. There's splashback."

"American toilets are dreadful," chimes in Duncan.

The plastic squeaks as Gerba tilts forward to warm his face. "I don't really know if one is cleaner than another. I haven't done that study yet," he says, the campfire reflecting off his glasses. "But why do you guys have narrower holes?"

"We've got smaller butts," replies Duncan, suppressing a smile.

Peggy speaks up: "Would anyone like another marshmallow?"


We break camp early on our last morning; Gerba has to get back to do a midday radio interview. "I think people are finally recognizing how important sanitation is," he says. "Ten years ago I was talking about this same stuff and nobody was calling me." Now they are. Gerba receives up to 30 telephone messages a day, ranging from questions about the microbial dangers of water wells to the effectiveness of natural wetlands in treating wastewater, currently one of his lab's primary areas of study. Germs are also a hot topic, thanks in part to a 400 percent rise in salmonella outbreaks over the last 40 years and a spike in the incidence of E. coli infections. Everyone hopes that our camping trip will contribute in some small way to the good fight.

As we pack, Gerba comes around and asks each of us to hold out a palm so he can test whether the soap and antibacterial gel we've been using has kept the enemy at bay. "I thought we'd be guinea pigs here," he says, dragging a swab over the front and back of Caroline's right hand, getting between her fingers, and tracing her wrist. Then he deftly breaks off the sullied tip and drops it into a screw-top vial filled with a solution called Colilert. Within 24 hours, Gerba will be able to tell if the sample tests positive for potentially harmful coliform bacteria by holding the vial up to the light and looking for a yellowish tint. (Following our trip, Dr. Germ will report that everyone using the antimicrobial gel has a clean bill of health. Sure enough, however, the hands of the control group that had been allowed to use only conventional camp soap prove to be a public health disaster waiting to happen. "They probably didn't rinse well enough," Gerba will say. "I figured that might happen.")

If this sounds like fairly primitive scientific spadework, well, it is. "Nobody's really studied backpackers," Gerba admits. "So we have to speculate." Still, there are some certainties. Gerba warns that the greatest risks for spreading germs exist among large groups at heavily trafficked campsites. He recommends dried food because bacteria can grow only where moisture exists. And more of us need to realize that simply being outdoors is problematic. "It's harder to control sanitation when you're camping," he says. "You're always gambling—you're playing an odds game. My whole thing is keeping the odds in your favor, but people just don't think about it." They also don't talk about it. One reason the backcountry has received so little attention from microbiologists is that hikers don't usually report camping-related illnesses. "There is no
1-800-I-Have-Diarrhea number for backpackers," says Gerba.

Before heading down the trail, we make one more run to the furry-bottomed pool for water. You can already tell it's going to be another scorcher. Gerba leans against a rock shelf and eyes the pond. "I prefer
to filter in moving water," he says. "Every pool of water is an animal's toilet." Nonetheless, he steps forward and puts one of his EPA-approved purifier's tubes in the pond and the other in an empty water bottle.

"You've got to pump slowly, so the chemicals have time to react with the viruses," he lectures, levering the handle. "Only pump as much as four liters at a time."

Clare is peering into the water bottle he's trying to fill. It remains empty. "I think you've got the hoses on the wrong way, Chuck," she says.

Gerba stops pumping and looks at the tubes. "That's the..." he stammers and pumps the purifier once more. "Is it blowing bubbles?" Clare nods. "Oh, God," he says.

"Don't swear," she tells him.

"Oh, God!"

He rights the situation, and after the bottles are filled the group bulls through the bushes between the pool and the trail. Gerba leads, moving faster than he's walked all weekend. At the mouth of the canyon he actually bolts ahead, pausing occasionally and looking back impatiently, as if we're suddenly holding him back. Then, damned if he doesn't flat-out disappear on the long, steep descent to the parking lot, where his truck is parked by a couple of portable toilets. When we stride into the lot half an hour later, the professor is sitting on the tailgate, rummaging through his stash of vials.

"Look at this swab—no dirt, no nothing!" Gerba exclaims, leading us over to the brown hut where he'd run the swab along the seat and door handle in search of contamination. Of course, he won't be sure it's clean for another day, after he gets a chance to run tests, but he's satisfied for now. He swings open the door, winking at Clare and Jenny. Without a doubt, Chuck Gerba has found the cleanest place in nature.

Andrew Tilin is a former senior editor of Outside.
PHOTO: Timothy Archibald

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