What Are The Chances Of Picking Up An Infection In A Public Restroom?

If you cringe at the idea of microbes lurking on toilet seats, faucet handles, and door knobs in toilet facilities in malls, parks, convenience stores, restaurants, and (horrors!) truck stops, chances are you wait to use the bathroom at home whenever possible. But if you just have to "go" when you are on the go, don't worry, chances are you aren't going to catch any germs.

Is There a Factual Basis for Bathroom Paranoia?

It's not like there weren't lots of different kinds of germs in public restrooms. The natural home of E. coil is, after all, feces. Everyone's bowel movements involve movement of E. coli. Most strains of this bacterium, fortunately, don't cause disease.

Everyone's skin harbors some staph bacteria. These are easily transferred from person to person. Fortunately, most strains of staph don't cause disease, either.

Public toilets host Streptococcus and GIardia bacteria (the latter organism causing an especially unpleasant kind of diarrhea with a condition known as "purple burps"), colds viruses, hepatitis A, and some of the organisms that cause sexually transmitted diseases, including gonorrhea, chlamydia, and syphilis. However, these organisms don't necessarily survive long enough on flat, hard surfaces to cause the next user of the toilet disease.

How Long Do Common Germs Survive in Public Bathrooms?

Different germs survive for different lengths of time in different places in public toilet facilities. Let's take a look at which germs you are most likely to encounter.

• E. coli in large numbers can cause symptoms like those of food poisoning. It's most often acquired by actually ingesting contaminated feces that gets into your food either at a meat packing plant (when the "guts" of the animal are not separated from other parts during butchering) or from the hands of food workers who do not wash their hands after they use the toilet. About five percent of public toilets harbor this germ, but you would get it by being splashed with the water the toilet uses to flush. Even if the toilet bowl is empty, the rinse water can transmit the germ. However, you won't be infected unless this water finds its way into your mouth.
• Shigella is the microorganism that causes shigellosis, a particularly unpleasant form of diarrhea that usually causes blood in stools, fever, abdominal cramps, and some vomiting. This diarrhea can last up to three weeks. This is a condition you are not especially likely to encounter in the North America, Australia, or Europe except when there is a water shortage and multiple people defecate into the same toilet without flushing. However, there are 165 million cases and 1 million deaths from this disease every year worldwide. It can be transmitted by the splash of water from the bowl.
• Giardiasis is caused by a protozoan, a one-celled animal, that can survive for long periods rolled up as a cyst. It's typically something people get by contact with animal waste, although there are groups of homosexual men who, how to put this, transmit the disease during intimate activities (up to 20% of gay men in some locations in the United States). Giardiasis causes several weeks of diarrhea with a condition known as "purple burps." It's important to avoid swallowing the cysts. If you don't engage in anal-oral sex, you'll avoid this problem by never drinking from streams in the wild, no matter how pristine they appear, and by washing after you use a public toilet.

Can You Really Get Gonorrhea from a Toilet Seat?

E. coli, giardiasis, and shigellosis are diseases people actually get from public toilets (although not very often). Sexually transmitted diseases are what people fear they can get from toilet seats. Let's take a look at the transmissibility of these microorganisms.

• HIV is not transmitted in public toilets, unless it is by sex in public toilets. The virus does not survive outside the human body, even in urine or feces, long enough to be transmitted to another person. Simply swallowing the virus would not be enough to cause an infection in most cases.
• Gonorrhea can be transmitted through contact with vaginal secretions, semen, mucus, and skin secretions. It is unlikely to be transmitted by saliva unless the saliva is vigorously inserted into another person. The bacteria that cause gonorrhea are detectable in urine, but you can't get gonorrhea by sitting in that urine. As one doctor puts it, "The only way you are going to get gonorrhea on a toilet seat is by having sex with an infected person while on that toilet seat."

• Syphilis in very, very, very rare instances could be transmitted by secretions of a highly infectious person (someone who has an unusually high concentration of the bacteria in his or her bloodstream) left on a toilet seat then coming in contact with an open cut in the backside or genitals of the next user. There are many places, by the way, where syphilis is essentially unknown, that is, almost no one has it.
• HPV (human papillomavirus) usually requires skin-to-skin contact. The virus will not survive on a toilet seat. 
• Herpes, in theory, could be transmitted on a toilet seat in the same way as syphilis. There is only report of this in the English-language medical literature, and this occurred on a home toilet, not a public toilet.

There, are however, certain germs that are transmitted in the spray of water that goes up when a toilet is flushed, even if the water appeared to be clean. These include:

• Norovirus. This virus causes up to 90 percent of all cases of viral "stomach flu." People continue to spread the virus long after symptoms subside. The virus can be spread in an aerosol. If you happen to come in contact with the toilet spray, you can get a norovirus infection. 
• Tuberculosis. We usually think of tuberculosis as a lung infection, but it can also be an intestinal infection. TB bacteria are very easily mixed with water droplets in toilet spray. It is possible to catch TB in a toilet, although it would usually take multiple exposures.
• H1N1 flu can be transmitted in toilet spray after the toilet is used to collect vomit. It is not easily transmissible through feces.
• Hard to manage bacteria infections such as Clostridium difficile, vancomycin-resistant Enterococcus, and methicillin-resistantStaphylococcus aureus (MRSA) tend to persist on toilet seats even after cleaning. However, you are not likely to encounter them outside of hospitals and care facilities.

READ Gonorrhea: A Superbug Becoming Increasingly Resistant to Antiobiotics

The bottom line is that it is not impossible to catch an infection in a toilet. It's just unlikely. And there are things you can do to lower your risk.

• If the toilet has a lid, close it before you flush.
• Don't face the toilet when you flush.
• Wash your hands both before and after you use the toilet. You don't want to transmit an infection from somewhere else (especially staph or step infections) to your privates.
• Avoid toilets in airplanes as much as possible. They are especially likely to harbor norovirus.
• Use the protective paper sheet or spray the toilet seat with disinfectant before using. 
• Beware toilets that are seldom used. They can harbor a biofilm, a naturally occurring sheet, of infectious bacteria. Some species of bacteria, such as Shigella, E coli, C difficile, severe acute respiratory syndrome (SARS) coronavirus, and norovirus can survive for three months or even longer.