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Mon 8 Oct 2007 - 9:01 pm UTC
Health professionals universally demand that we wash our hands after using the bathroom. While it is true that a host of diseases are carried on the hands, that does NOT mean that simple hand-to-genital contact-as in male urination-is a significant contributor to those germs. Oral-genital contact doesn't seem particularly risky, after all. The need for handwashing after fecal contact is obvious, but is there any PRIMARY evidence for the spread of germs due to male urination (assuming that nobody's peeing on their hands)?
What have I found out? Well, in spite of the facts that the Centers For Disease Control and the American Society for Microbiology sponsor a website devoted to getting people to wash their hands in the bathroom (http://www.washup.org/page01.html ), bathroom handwashing remains a motherhood issue.
Tue 9 Oct 2007 - 3:26 am UTC
Interesting question, and one that (believe it or not) I've wondered about myself.
As you're already well-aware, washing ones hands is considered de rigueur in the public health community, as a means of reducing transmission of infectious diseases.
The practice stems from a combination of good medical science, common sense, pragmatism, and social etiquette.
In a nutshell, we certainly know enough about disease transmission to strongly recommend hand-washing as a reasonable public health measure.
Not much is really known about the specifics of many common diseases, in terms of the relative importance of contamination from, say, door knobs vs shaking hands, sneezing vs wiping, and so on. So it's hard to quantify the specific role of urination as a means of disease transmission.
Your question contained a big caveat: "assuming that nobody's peeing on the hands". Nobody's pooping on their hands either, at least not intentionally. But a person's hands can certainly, if inadvertently, come in contact with urine as well as feces, so I've kept this possibility in consideration in answering your question.
Bottom line: disease organisms can certainly get onto the hands during urination from either skin or from urine, and these can then lead to disease transmission. How big a contributor this is to overall disease transmission is not known, but I didn't come across anything to suggest it rivals contamination from fecal matter as a contributor to disease. But even if urination is not a big contributor, the recommendation to wash hands after any restroom use is a sensible one, simply because restrooms are where sinks are located...the several visits that people typically make a day are the ideal occasion to wash hands, and lower the germ count.
For starters, a bit of background on the history of hand-washing and public health:
Why is handwashing important?
"...Remember Ignaz Semmelweis? Of course you don't. But you're in his debt nonetheless, because it was Dr. Semmelweis who first demonstrated over a hundred years ago that routine handwashing can prevent the spread of disease.
...In an experiment considered quaint at best by his colleagues, Dr. Semmelweis insisted that his students wash their hands before treating the mothers--and deaths on the maternity ward fell fivefold.
..."This was the beginning of infection control," Dr. Gerberding said. "It was really a landmark achievement, not just in healthcare settings, but in public health in general because today the value of handwashing in preventing disease is recognized in the community, in schools, in child care settings, and in eating establishments."
As pinkfreud noted in a comment, above, the warm, moist groin area is generally a beehive of bacterial activity:
Aerobic microbial flora of intertrigenous skin.
"...The incidence of gram-negative rods was 17% for the axilla, 13% for the groin, 10% for the toe web, and 9% for the finger web. Klebsiella, Proteus, and Enterobacter were the predominant organisms, in that order. The highest incidence of Staphylococcus aureus was in the groin (12%) and toe web (11%)."
Oral-genital sex can also be a route of disease tranmission:
"...Chlamydia can be transmitted during vaginal, oral, or anal sexual contact with an infected partner.
...HSV type 1 most commonly causes sores on the lips (known as fever blisters or cold sores), but it can cause genital infections through oral-genital or genital-genital contact.
...Syphilis is passed from person to person through direct contact with a syphilis sore...Transmission of the organism occurs during vaginal, anal, or oral sex."
Human urine is normally thought to be pretty clean stuff:
Human urine normal flora
"...The reason human urine in the bladder is usually sterile is because it's never exposed to bacteria."
However, research is beginning to show it may not be as prisine as is commonly thought:
Viable but Nonculturable Bacteria Are Present in Mouse and Human Urine Specimens
"...Urine specimens obtained from human female volunteers with or without an active urinary tract infection were found to contain, on average, significantly more viable than culturable forms of bacteria."
[NOTE: Meaning that the urine might look sterile, but actually not be, as it contains organisms that don't show up during laboratory cultures]
At least several diseases are thought to be transmitted (at least partly) through contact with human urine:
Disease Fact Sheet Series: Hand washing
"...Diseases may also be spread when hands are contaminated with urine, saliva or other moist body substances. Microorganisms which may be transmitted by one or more of these body substances include cytomegalovirus, typhoid, staphylococcal organisms, and Epstein-barr virus. These germs may be transmitted from person to person or indirectly by contamination of food or inanimate objects such as toys. "
Disease transmission models for public health decision making
"...The life cycle of the schistosome begins with the sexual pairing of adult worms in the blood vessels of the host and the production of copious numbers of eggs, a fraction of which are excreted in feces (or urine in the case of S. haematobium)"
Wild Rodents and Rabbits: Potential Zoonotic Diseases
"...Lymphocytic choriomeningitis (LCM) is caused by the arenavirus commonly associated with hamsters, but does infect mice... Transmission to humans is through contact with tissues including tumor, feces, urine, or aerosolization of any one of these."
The Leptospirosis Information Center
"...In humans, viable bacteria will be present in the urine after about 2 days from the exposure (day E2), and they will usually remain present for a few weeks after illness, but there are recorded cases of humans shedding the bacteria for up to 11 months. Treatment with antibiotics can reduce the symptoms and also reduce this shedding time, but in most patients their urine contains detectable bacteria for many weeks after clinical recovery. Our advice is to assume some risk from urine for up to 12 months after the acute illness has faded."
HEMORRHAGIC FEVERS DUE TO CRIMEAN-CONGO HEMORRHAGIC FEVER, EBOLA, LASSA, AND MARBURG VIRUSES
"...Transmission of Viral hemorrhagic fever (VHF)...has been associated with reuse of unsterile needles and syringes and with provision of patient care without appropriate barrier precautions to prevent exposure to blood and other body fluids that contain the virus (including vomitus, urine, and stool)"
On the other hand, the presence of disease organisms in urine does not always lead to demonstrable routes of infections. Medical researchers often can't say one way or the other whether contact with urine would be a significant -- or even a possible -- route of transmittal:
Lyme Disease - Introduction & Disease Transmission
"...Although in theory Lyme disease could spread through blood transfusions or other contact with infected blood or urine, no such transmission has been documented. There is no evidence that a person can get Lyme disease from the air, food or water, from sexual contact or directly from wild or domestic animals."
Does Contact with Urine and Blood from a Rabid Dog Represent a Rabies Risk?
"...Human-to-human transmission of rabies once a patient with rabies has been admitted to a hospital has always been a serious concern. Other than the report of transmission via corneal transplantation, there are no reliable reports of such transmission . Although rabies virus has been isolated from urine sediment after centrifugation (in 1 of 8 samples) , and although the detection of rabies virus RNA in urine samples is as accurate a diagnostic tool as its detection in saliva samples , we failed to demonstrate the infectivity of urine"
Risk assessment and management of possible transmission of Lassa virus during two flights
"...During the two flights the patient had no cough but a urinary tract catheter which was disconnected from the reservoir and released relevant amounts of urine on the passenger's seat. The patient's urine was tested positive for Lassa virus, which was taken into account for the risk assessment and contributed to the decision to trace back co-passengers potentially exposed.
...In this investigation, the leakage from the urinary catheter reservoir influenced the risk assessment and the decision for a passenger trace back as Lassa fever is primarily transmitted by urine of rats. Nevertheless, no contact passenger revealed Lassa virus. Our investigation confirms that the human to human transmission of Lassa virus during flights is unlikely if no haemorrhagic symptoms appear at this time."
And for an ironic twist, hand-washing might increase the danger of certain infection routes, if the disease organisms are not destroyed after they go down the drain:
Fecal Bacteria and Human Viruses Found in Upper Florida Keys
"...Genetic material from intestinal viruses, which can cause disease and are spread through infected human feces and urine, were found throughout the sampled area
...The detection of these bacteria near shore suggests that land-based sources of sewage pollution, like cesspits and septic systems, may be significant contributors."
All this boils down to a lot of possible ways that the simple act of urination could lead to contaminated hands, and to transmission of disease. It doesn't tell us, though, how often this happens, or how significant a route of transmission this might be.
However, if you were sitting on the plane next to the sick guy with the leaky catheter...wouldn't you be just a wee bit worried?
Let me know if there's anything more you need on this.
Wed 17 Oct 2007 - 12:20 am UTC
Thanks so much! We look forward to seeing you back here sometime soon.
In the mean time...keep those hands clean!
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