This article first appeared at College of Agriculture and Life Sciences at University of Arizona more than ago. Some information may no longer be current.

Dr. Germ

University of Arizona Professor Charles P. Gerba

Here a germ, there a germ, everywhere a … wait! With all the medical and technological advances in the last century, shouldn't germs and infectious disease be a thing of the past?

Not so fast. One hundred years ago, infectious disease was the leading cause of death. By 1980, it had fallen to number 5, but about 10 years ago, it managed to climb its way up to number 3. And, according to Professor Charles P. Gerba of the University of Arizona Department of Soil, Water and Environmental Science, it'll most likely find its way back to the number 1 spot.

"Germs follow us around all day. They are opportunists," says Gerba, who's been on such shows as Dateline, 48 Hours, the Today Show, 20/20, and Good Morning, America. Some of the reasons why infectious disease will move up the chart include the globalization of commerce and travel, changes in drinking water and food supply production, and evolution -- a genetic reassortment, as Gerba calls it.

Widely known as Dr. Germ, he has become the nation's expert on domestic and public hygiene. He's even been featured in the National Enquirer five times. Not surprising for a man who quips, "I study toilets -- that takes guts."

The toilet plume

How does a UA professor get involved in studying toilets in the first place?
Gerba was an assistant professor for eight years at Baylor College of Medicine, where he studied waterborne diseases. He worked with Joseph Melnick, an international leader in the identification and control of virus diseases and one of the founders of the field of virology. He led the team that developed thermo-stabilized live polio vaccines, making it possible to immunize millions of people in countries without deep-freeze storage facilities.

"I study toilets -- that takes guts."

-- Charles P. Gerba

One day at work, Melnick took the usual bathroom break when a light bulb went off: He wondered if a plume of contaminated water droplets was ejected into the air every time a toilet flushed. He ran down to Gerba's office, grabbed him, took him back to the men's room, pushed Gerba into the stall and said, "Gerba, you're looking at your future."

Melnick was right. Gerba has made quite a name for himself by studying public toilets and other places where germs lurk. In 1975, Gerba published a scientific article describing the phenomenon of bacterial and viral aerosols due to toilet flushing. When this aerosol of contaminated water is ejected into the air, it lands on everything in the bathroom, including your toothbrush. According to Gerba, this isn't just another scare tactic to get men to put the top down.

During the study, gauze pads were placed around the experimental bathroom. Close-up photos of the germy ejecta, according to Gerba, looked like "Baghdad at night during an air attack." The study showed that significant quantities of microbes floated around the bathroom for at least two hours after each flush. Gerba discovered that a lot of virus fell on those gauze pads.

And while the toilet stall was the beginning of Gerba's distinguished hygiene studies, even he was astonished to find out that bathrooms aren't the germiest of places. Your kitchen is. Gerba, who's fond of quipping, "I've published several toilet papers," says the kitchen is one of the germiest places in the house.

If this doesn't make you wake up and smell the coffee, nothing will: Your kitchen is even more contaminated with bacteria than the toilet bowl. "That's why your dog likes to drink out of the toilet," Gerba says.

The sponge

The worst offender in the kitchen? The kitchen sponge or dishcloth, where fecal bacteria from raw meat festers in the damp, nurturing environment. The next worst offender is your kitchen sink. This is where vegetarians have a definite advantage since they don't bring raw meat into their homes. There's less chance of E. coli and salmonella spreading, but they still have to be on the lookout for viruses and parasites.

Third on the Most Contaminated list is the bathroom sink. Then, it's back to the kitchen. The cutting board comes in at number four, then the kitchen floor. The bathroom floor and the bathroom counter are numbers six and seven, respectively.

And the least contaminated, according to Gerba's research? The toilet seat.

"If an alien came from space and studied the bacterial counts, he probably would conclude he should wash his hands in your toilet and crap in your sink," says Dr. Germ, with cheerful bluntness.

Fifty to 80 percent of all food-borne illnesses originate in the home. Food-borne pathogens cause 6.5 million cases of gastroenteritis and 9,000 deaths per year. Twenty percent of food-poisoning cases are blamed on home contamination, more than any other source.

The coffee cup

Feel the need to get away from this story and take a little coffee break? You might want to hold off on that plan: Twenty percent of the coffee cups Gerba's tested are oozing with fecal bacteria, thanks to the sponges that clean them.

As for the water that makes that cup of coffee, Gerba recommends treatment at the tap, especially for sensitive populations, and notes, "Arizona has the largest number of ground water wells that are not treated in the United States." Gerba defines sensitive populations as infants, the elderly, pregnant women, and people whose immune systems are compromised. "We're all going to fall into one of these categories at some point."

He recommends an activated charcoal filter or reverse osmosis for treating your tap water. Interestingly, there's not much difference between bottled water and tap water in terms of total bacteria.

Gerba always knew he wanted to be a scientist, even as a young boy. He had his heart set on being a chemist, and he longed for a chemistry set for Christmas. His mother mistakenly bought him a microscope, but that opened the door -- or Petri dish, as the case may be -- to a lifelong passion for germs.

Despite being the nation's expert on hygiene, his life is hardly glamorous. He spends a lot of time crawling around the floor in public bathrooms, and the cops have been called on him twice.

"I was on my knees in front of a public toilet, when I heard a tapping on the stall," Gerba recalls. "A policeman asked, ‘Are you the only one in there?' And I said, ‘I'm a scientist. I'm doing research.' The cop responded with, ‘Yeah, right, I arrested one of you last week.'"

The single man

But don't accuse Gerba of being a man obsessed. "I'm not germophobic because I know where the germs are," he says.

If you are a germophobe, when it comes to pigsties, you probably think of single men first. They may appear to be wallowing in filth, but single men's abodes actually tend to have lower bacteria counts since they rarely clean and don't spread the germs around. Sparkling clean does not always equal germ free. In fact, women's public restrooms contained twice as much fecal bacteria as men's, probably because women are often accompanied by small children and babies in need of a change.

Laundry is yet another germ fest. Turns out, it doesn't all come out in the wash. Never one to mince words, Gerba says, "Basically, if you do undergarments in one load and handkerchiefs in the next, you're blowing your nose in what was in your underwear." It's better to make underwear the last load. Use chlorine bleach, which will clean both the clothes and your washing machine.

"Germs never give up -- they always find a way. We're always discovering new ones."

Especially fascinating for Gerba is how some viruses affect the brain and the possibility that they could be a contributing factor to mental illness. Other studies show that viruses could be responsible for obesity and common illnesses. For example, ulcers used to be attributed to stress and lifestyle, but now 95 percent of ulcers are attributed to bacteria.

"I like to use humor to get people's attention, but it's nice to let people know there's something they can do to prevent infectious diseases." Plus, Gerba says, it's just plain fun. "How many people get paid to study public toilets?"

This from the man who actually named one of his two sons after E. coli. Peter Escherichia Gerba, now a high school English teacher, used to get decked out for Halloween as -- what else? -- bacteria. Gerba's wife put her foot down when it came time to name their second son, Phillip, who is a professional clown.

The remote control

On a more serious note, however, Gerba is proud of work he's done that actually helps to save people's lives.

Numerous public health campaigns have focused on the need to reduce the rising use of antibiotics. When antibiotics are used unnecessarily, particularly among children, it leads to an increase in drug-resistant bacteria.

"With just a simple cleaning and disinfecting program -- and no other change in behavior -- we saw improvements that ranged from 10 to 37 percent -- clearly important for public health in this country.

"When you become a parent, you find yourself becoming an expert on contagious disease," Gerba says. "You can't stop children form getting sick, but there are simple things you can do -- at home, at work, or at a day-care center -- to keep disease from spreading.

"Lack of knowledge about where germs lurk is a real health problem because people touch these objects and 80 percent of infections are spread through hand contact. The solution is to practice proper hand hygiene by washing with soap and water or by using an alcohol-based sanitizer.

"Antibacterial soaps would be good if they worked, but they don't seem to do anything," Gerba says. As to reports that these soaps are creating supergerms, Gerba maintains, "There's no evidence that the antibacterial soaps make bacteria stronger." Disinfectants, on the other hand, "blow up the germ. Disinfectants have worked for 100 years and are still as good as they were. Disinfectants kill both viruses and bacteria." Chlorine bleach, alcohol, and hydrogen peroxide are all good disinfectants.

Gerba shared some interesting tidbits about hand washing and spreading germs: 95 percent of people say they wash their hands after using a public bathroom, but only 67 percent actually wash their hands. Only 33 percent of those who do wash their hands use soap. And only 16 percent really wash their hands long enough.

Every three minutes, a child brings his hand to his nose or mouth. Every 60 seconds, a working adult touches as many as 30 objects. (If you're traveling, by the way, you might want to disinfect that remote control for the TV. That's where the big bacteria boys hang out in a hotel room. Some viruses can survive on surfaces for up to 72 hours.)

Speaking of working adults, the phone comes out as the germiest object in the office, followed by the desktop, keyboard, mouse, fax machine, and photocopier. Where are the least germs in the office?

By now, you should have guessed: the toilet seat.

Accessed: February 17, 2005 at

Return to Previous Page

Copyright 2023 All rights reserved. rss Subscribe to our RSS
Information provided here should not be relied on to diagnose, treat, cure or prevent any condition, disease or illness. Please consult with your physician or health care professional for guidance on any health concern. is a commercial website and is not affiliated with any government agency, university, or private medical center. COMPENSATION DISCLOSURE: This site may be compensated for products promoted here. Read our Privacy Policy and Terms of Use.