US, WASHINGTON (NEWS OBSERVATORY) — Doctors from Britain and Poland monitored how a new type of coronavirus behaves when released into the water, and also evaluated the risk of drinking untreated water in two dozen countries. It turned out that in rivers and lakes it can be up to 25 days, and most of all this can be feared by Great Britain, Spain and Morocco.
Preliminary results of the study were published in the medRxiv electronic scientific library.
“Natural reservoirs can serve as reservoirs and distribution routes for a new type of coronavirus (SARS-CoV-2). In many countries they pose a real threat to health, and therefore if leaks from sewers have recently occurred, then people and animals come into contact with river and lake waters need to be minimized, “scientists write.
Almost from the first days after the outbreak of a coronavirus infection, scientists know that SARS-CoV-2 affects cells not only in the lungs, but also in other body tissues, including inside the mucous membrane of the nose, esophagus, blood vessels and heart, as well as several others organs.
This, in particular, explains why there are so many viral particles in the waste of human life. Together with waste, these particles fall into wastewater and sewage. Scientists have been debating for several months about whether SARS-CoV-2 can spread in a similar way and what role this channel of its transmission between humans or animals plays in the evolution of the virus.
On the one hand, scientists have recently proven that the virus can actually spread through the digestive system. On the other hand, the results of research by Italian and Spanish doctors showed that modern wastewater treatment systems should completely neutralize SARS-CoV-2 before it even gets into water bodies.
A group of British and Polish epidemiologists led by Associate Professor of Exeter University (Great Britain) Jamie Shattler was interested in what would happen if some of the infected sewage water gets into water bodies before treatment.
Nature and virus
To answer this question, scientists tried to determine how long SARS-CoV-2 particles can remain in water and still retain the ability to infect new victims. Shatler and his colleagues conducted a series of their own experiments, and also analyzed the results of other experiments.
As it turned out, the virus can be in the water for a very long time, if its temperature is low enough. In typical sewage, as well as the waters of rivers and lakes, according to Shatler and his colleagues, the virus lives for about 25 days. Based on these estimates, epidemiologists tried to estimate how many particles of SARS-CoV-2 can be in the water bodies of two dozen countries with the highest number of cases of COVID-19.
In their calculations, scientists proceeded from the assumption that for infection it is necessary that there are at least 100 virus particles for every 100 ml in the water of rivers and lakes. In most countries of the world, this indicator, as the researchers found, is easy to achieve or even exceed several times after the discharge of sewage water or its leakage into fresh water bodies.
In particular, most of all this can be feared in countries where patients are concentrated at one point, a relatively small amount of water consumed per capita, and relatively low water temperatures in rivers and lakes. The most vulnerable states in this regard were Spain, the United Kingdom and Morocco: within 24 hours after major wastewater leaks in the water of rivers and lakes in these countries, almost 500 virus particles for every 100 ml can be found.
On the other hand, northern countries with a low population density, as well as some tropical and equatorial states rich in water resources, were least exposed to this risk. The first included Canada and Russia, and the second – Indonesia, Venezuela, Australia and New Zealand.
“Given that the virus remains stable in a very large pH range at low temperatures, it is also possible that it will survive in the waters of the seas and oceans. ACE2 receptors in many cetacean species are very similar to their human counterpart, so they can be vulnerable to SARS-CoV-2. Of particular concern in this regard are whales, since large volumes of water constantly pass through their throats, “the scientists concluded.
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Article is written and prepared by our foreign editors from different countries around the world – material edited and published by News Observatory staff in our US newsroom.