This probably sounds germophobic, but how come bath houses and onsens don’t spread disease if microbes love moisture and warmer environments? For example, onsens and baths have supplies for shaving, and when you shave there are always open wounds being made, so how doesn’t it spread something like hepatitis if someone with hepatitis shaves, cuts themselves in the bathhouse, and the next person sits in the same little stall? Other things like warts….why isn’t there an epidemic of people contracting something like plantar warts from using onsens and bath houses if the virus loves that kind of environment and many people pass through it in a day/week?
I’m just curious if this has ever been studied and why it is clearly not a public health problem.
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The fact that we’re not suffering from a warts epidemic should be enough answer, I suppose. The idea is to clean yourself before you go in. All the way with soap and shampoo. So there should be as few germs in there as possible. The water is rotated out. And don’t drink it.
Because it’s kept clean, and people clean themselves, and everything is constantly being rinsed off?
I think onsens are supposed to change the water fairly frequently. There was news recently that a famous onsen didn’t change the water for at least 6 months, and that made people raise a stink (pun absolutely intended).
The water are changed like twice a day, and there are water quality check like once and hour.
Quick google search shows a recent study:
> Legionellosis is a serious bacterial infection characterized by atypical pneumonia primarily due to infection with Legionella pneumophila, and bathing can be a potential cause of this infection. Legionellosis was first identified in 1977, and it is caused by Gram-negative bacteria belonging to the genus Legionella. Legionellosis remains an important public health threat, particularly in Japan, where the population is rapidly aging, thereby becoming more at risk of developing severe disease and accompanying life-threatening pneumonia. The bacteria are most commonly transmitted via the inhalation of contaminated aerosols produced and broadcast via water sprays, jets or mists. Infection can also occur via the aspiration of contaminated water or ice, or through inhalation of contaminated dust. Because the signs and symptoms of Legionnaires’ disease (LD), as well as radiographic imaging are similar to pneumonia caused by other pathogens, a specific diagnostic test is required, such as a urine antigen detection test. Six clinical and laboratory parameters, a high body temperature, a non-productive cough, low serum sodium and platelet counts, and high lactate dehydrogenase (LDH) and c-reactive protein concentrations can be used to reliably predict the likelihood of LD. The first choices for chemotherapy are fluoroquinolone and macrolide antibiotic drugs. The main goals of LD prevention measures are 1) the prevention of microbial growth and biofilm formation, 2) the removal of all biofilm formed on equipment and in facilities, 3) minimizing aerosol splash and spread, and 4) minimizing bacterial contamination from external sources. It is apparent that, in Japan, where hot spring (onsen) bathing is common among aged people, strict regulations need to be in place – and enforced – to ensure that all Japanese onsens and spas provide a safe environment and undertake regular, effective infection control practices.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872820/
All the above comments and onsen water is usually either rather alkaline or acidic (depending on the onsen) which is probably not ideal for bacteria used to living on human skin.
It’s also not just warm, but often almost uncomfortably hot.
If you google 温泉 and 水虫 (athlete’s foot), you’ll find enough articles detailing onsen as a risky place to get it, despite all the washing / rinsing they do. So onsens are not completely risk-free of catching something either
I think to contract warts you actually need to have an opening in the skin like a cut or a wound where the virus can enter? If I’m mistaken, please let me know. I think most people would cover up any wounds or cuts at the onsen for etiquette reasons.
I’m trying to find the article, but a couple months back there was a sento that wasn’t being properly cleaned and a bunch of people got sick.
Edit: https://edition.cnn.com/travel/article/japanese-spa-water-scli-intl/index.html
You can smell antiseptic…
Water is really hot and kills germs
Your skin is incredibly resistant to infection and disease
They clean the onsen and change the water
Onsen water is not pure water, it has a lot of dissolved substances which make it harder for bacteria to grow
To add to most answers so far, onsen are quite a bit warmer than body temperature, which by itself kills a LOT of the bacteria that put healthy people at risk. It won’t kill all of them, but the ones that are optimised for 37 C have a more difficult time (same reason you get a fever when you are infected, it makes the bacteria weaker)
They are places where all sorts of things can and do spread. Obviously a well maintained one which is not crowded will have lower risks than one at the other end of things.
That said in general the risks are low and not worth worrying about.
Saw an old bloke getting changed before heading into the baths. He had full shit himself and was examining and dealing with the load in his pants. I was just leaving but I sure hope he had a damn good shower before getting in. I also see a lot of people not bothering with the pre-wash these days – a splash of water to the groin at best.
It’s a fair question you ask, I think the first thing is that no one is complaining about getting herpes or foot warts from sitting on a seat in the steam room at an onsen, the risk is pretty low. Hopefully that puts your mind at ease.
However.
As a proper germaphobe, whenever I go to the onsen I never sit on or touch anything. I just go into the bath water and get out. Even when I bathe beforehand at the shower section, I squat I don’t sit on the seats. Not a fan of sitting naked on a seat someone else has just sat their naked bits on.
Shoes off of course is a concern. I’m not a fan, but at least that risk is similar to a normal pool (which are known wart spreaders). If I could wear water shoes I would. This is why I usually go to private onsen.
You will notice that they are closed at some point during the day. That’s when all of the cleaning is done and the water is changed
My wife (Japanese) told me they use something they don’t use in the states. Something they put in the water that makes it damn near impossible to spread germs. That’s why I was surprised that no one had to wear shower shoes of some type. Also surprised at the older female custodian coming out and cleaning while I’m standing there buck naked.
Well, if you go to that one in Fukuoka…
Legionnaires Disease. Huge scandal about it in onsen every few years., lots of people got sick, some died. All to do with costcutting.
I dunno. Every time I go there is a old lady that walks in to clean the place. There always seems to be someone cleaning / disinfecting something. Maybe that’s part of it. I get the feeling that bath mold is something Japanese are concerned with more than some other foreign countries
Oh, but they absolutely do. I am a frequent onsen visitor and I get athlete’s food once in a while, which is not always easy to get rid of.
Otherwise, everybody (not everybody, some assholes don’t) wash themselves before bathing and the bath water itself is usually with a high mineral content and hot enough to be relatively safe.
Recent article about a famous and popular inn where they didn’t change the water.
[https://www.japantimes.co.jp/news/2023/02/24/national/ryokan-bathwater-bacteria/](https://www.japantimes.co.jp/news/2023/02/24/national/ryokan-bathwater-bacteria/)
They need regular cleaning and maintenance. I did see a report on TV recently about how one local place only cleaned out the place a few times and germs/bacteria built up to unsafe levels.
But as for open wounds, why doesn’t lets say someone with aids who swims in a pool with a small cut infect everyone else with aids? Clearly things don’t quite work like that.
Edit: Here is the article
[Inn ‘sorry’ for changing out bath water only twice a year](https://www.asahi.com/ajw/articles/14850008#:~:text=FUKUOKA%2D%2DThe%20top%20official,add%20chlorine%20for%20disinfection%20purposes)
>FUKUOKA–The top official of a luxurious onsen inn in Chikushino, Fukuoka Prefecture, apologized on Feb. 28 for changing the water in its large bath only twice a year and for regularly failing to add chlorine for disinfection purposes.
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>“I sincerely apologize from the bottom of my heart,” said Makoto Yamada, president of the management company of the Daimaru Besso inn, at a news conference in Fukuoka.
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>The inn only changed the hot water in its large bath two days a year, even though a prefectural ordinance requires it to do so at least once a week.