The COVID-19 survives well in the water (but we’re going to catch-not by swimming)

Jean-François Cliche
The SunLa COVID-19 survit bien dans l’eau (mais on ne l'attrapera pas en nageant)

La COVID-19 survit bien dans l’eau (mais on ne l'attrapera pas en nageant)

La COVID-19 survit bien dans l’eau (mais on ne l'attrapera pas en nageant)


24 may 2020

Updated may 25, 2020 at 8h08


The COVID-19 survives well in the water (but we’re going to catch-not by swimming)

SCIENCE DAILY / “Is the virus of the COVID-19 can survive in unchlorinated water such as lakes ? Its envelope “fat” does it float on the surface for him to infect people who enjoy a good swim ?”, request Paule Bushel, of Quebec. From his side, Marie Morneau, also of Québec, would like to know : “When the pools will reopen, private and public, is the fact that you put the chlorine will ensure the safety of bathers against the COVID-19 ?”

In general, yes, the “family” of coronavirus (which includes the COVID-19, but many others also, of which four viruses are benign that give the common cold) survives well in fresh water, as long as it is not too polluted. A study published in 2009 in the scholarly journal Food and Environmental Virology found that it takes about 10 days for 99.9% of coronavirus are eliminated in tap water at 23 °C, and more than 100 days when the water is maintained at 4 °C. other work of the same kind published in the same year in the Water Research have concluded that, in the water of a lake, it takes 10 to 15 days before that 99 % coronaviruses do not die in the water of a lake.

Now, is this mean that swimming in the lake or in the swimming pools — if they end up not re-open — will be dangerous ? Essentially, no, because “the virus is so diluted in these conditions, where the risks are infinitesimal,” says the researcher of the Institut Armand-Frappier (INRS) and a specialist in coronavirus-Pierre Talbot.

Like other human coronaviruses, the COVID-19 is spread mainly by droplets from the patients expel when they cough, sneeze, or otherwise. When a droplet arrives on the hand of someone or on a solid surface, it remains fully in place with all the viruses it contains. But when she falls in the water, it is a different story : the droplet being composed almost entirely of water, it will mix with that of the pool or the lake, and the viruses it contains will so disperse, instead of being all concentrated in the same place. So if a swimmer passes by, the amount of virus that there is the risk of swallowing is likely to be very small, insufficient to cause the disease.

In addition, the lakes are large bodies of water that are frequented by relatively few people, which further reduces the risks. The swimming pools, they are of course more densely populated, but their water is chlorinated and the microbes die quickly.

This does not mean that contamination is impossible in the chlorinated water. We know of the virus that have the ability to be spread in public swimming pools, especially when the water is not adequately treated. But in general, it is not the coronavirus that do. Last year, theInternational Journal of Environmental Research and Public Health published a review of all of the outbreaks of viral associated with public swimming pools and documented in the medical literature since the 1950s. No it does not imply coronavirus. It was primarily a virus that spread mainly through the oro-faecal, such as enterovirus and norovirus (sources very frequent gastroenteritis) and hepatitis A. the Only exception is adenovirus, which can also cause gastros but also respiratory infections. However, adenoviruses are known to be very resistant outside of the human body, which is not (at all) the cases of the coronavirus.

In short, in the public swimming pools, it is much more the proximity of bathers between them (both in the water and outside, in the locker room, in the queue for the dive, etc) that the presence of the virus in the water which can be problematic.

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