16 September 2018

How Not to Draw Out More than Needed

What infections can you catch by visiting a pool?

In reality, there are many options. Of course, in a given area different pathogens may prevail. Unfortunately, we were unable to find any Ukrainian statistics on outbreaks of infectious diseases related to swimming pools. Therefore, we present data from other countries—primarily from the United States and Europe. It is unlikely that Ukrainian pools have a more perfect cleaning system or healthier visitors.

The top dangerous pathogens that can persist for a long time in chlorinated water and pose a threat to health, and sometimes life, include cryptosporidia, legionella, and pseudomonas. In addition to them—fungal and respiratory infections, including adenoviruses.

Cryptosporidiosis does not, unfortunately, have anything to do with cryptocurrencies; rather, it can survive in chlorinated water for more than a week, and when ingested causes diarrhea, stomach cramps, and nausea.

In studies that checked water from various pools, cryptosporidia were found in 10-15% of cases (1, 2).

Another dangerous pathogen, which is not affected by the presence of chlorine or high water temperature, is legionella. It causes a flu-like syndrome, or, if luck is worse, atypical pneumonia with a high mortality rate. We again could not find epidemiological data on Legionnaires' disease in Ukraine. Even our Ukrainian researchers describe only foreign statistics in their works (3).

And, unfortunately, this does not mean that Legionnaires' disease is not here... We came across a case where a Danish citizen, after staying at a hotel in one of Ukraine’s regional centers, returning home, fell ill with Legionnaires' disease. Efficient diagnosis and thorough analysis of facts led epidemiologists to a pool in Rivne, where water samples were taken and the pathogen was detected. Should we say that if the man had been local, hardly anyone would have talked about Legionnaires' disease (4).

According to some data, legionella can be detected in about half of hotel and sports center pools (5).

This bacterium especially loves jacuzzis. Interestingly, the main route of infection is water aerosol, whereas person-to-person transmission is not particularly common for this infection.

The top three most noticeable azards are finished with pseudomonas. It is often the cause of rashes on the body and ear infections and also loves to hang out in jacuzzis (6). According to data, it is registered in about 30% of pool water samples in studies (7).

Of course, the list does not end there. Other gut-dwellers, such as Escherichia coli, or Salmonella, are also often found in pool water, but they differ in weaker resistance to disinfectants and are therefore eliminated more quickly (8).

Fungal infections haunt visitors not so much in the water as in changing rooms, on benches, floors, swimming equipment (aids for fitness, cushions) and diving platforms (9, 10).

In addition, adenoviral infections can easily be contracted in pools, making visiting especially risky during epidemic periods (11).

Interestingly, amebae are found in the water of many pools; they themselves do not pose a threat, but they act as reservoirs for long-term storage and multiplication of Legionella and adenoviruses. Researchers showed that in 10 of 16 pools studied, infected amoebae lived there (12).

Microorganisms live in water and that is normal. We exist in a non-sterile environment; we come into contact with microbes, and this is quite routine for us—when it comes to saprophytic, calm, relatively indifferent microorganisms. A pool is a place where microorganisms are not welcome, where they are constantly treated with disinfectants, whose mechanism of action mainly involves oxidative processes. To survive in this harsh world, microorganisms must develop their super-skills and become more resistant to oxidative stress... and, at the same time, to the defenses of our immune system! After all, the first line of our immune cells is to attack foreign agents with free radicals. Having trained in chlorinated water, such a pathogen entering the human body is often already invulnerable to its immune defense. Therefore, an infection acquired at a pool can be as dangerous as nosocomial infections. This can have particularly sad consequences for people with weak immunity, children, and the elderly.

And even without infections, there are nuances...

Sweat, saliva, urine, skincare products and hair care products—creams, lotions, cosmetics, and other organic substances—upon interaction with oxidizing disinfectants form chlorine- and bromine-containing products, which, as it turns out, have even higher toxicity than the disinfectants themselves (13).

Disinfectants themselves often cause eye and skin irritation and can provoke respiratory syndromes, which sometimes occur as outbreaks (14, 15).

Modern combined water disinfection systems, such as including ozonation or UV treatment, create additional problems by increasing chlorine reactivity and the amount of its toxic derivatives (16).

This turns pool water into a container of free radicals. Guess what it does to your skin.

And what about children?

We cannot condemn the practice of taking children of all ages to the pool. Here are the facts from recent studies. According to them, visiting a pool at a very early age increases the risk of bronchitis and asthma. Researchers explain this by the aggressive action of chlorine and chlorine-containing products on the immature, delicate respiratory epithelium (17, 18).

And finally – a bit of trash

The American Water Quality and Health Council conducted a survey this year that showed more than half of respondents do not shower before entering a pool. A third of those who do shower before swimming do it for less than a minute, which, frankly, is not enough to clean themselves. Every fourth admitted that at least once they relieved themselves without leaving the pool (and who knows how many more did not admit?). 17% of respondents admitted that diarrhea would not stop them from using a pool where other people swim (19).

So what?

Whether to go to the pool or not is everyone’s choice. Sometimes the pleasure and health benefits of swimming outweigh avoiding some "phantom" risks that already fill our lives. However, we hope that the facts above will perhaps push the reader to the following:

Health and happy swimming!