Eric Gaucher, a doctor in environmental sciences, talks about how the virus has spread or is still spreading around the world today. He deduces that temperature is a major factor and predicts the end of the virulent phase for the summer. Grandstand.
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Is the Covid-19 flu, and its severe forms, a persistent phenomenon in summer or is it a seasonal illness linked to winter? Answering this question is essential for building a relevant deconfinement plan that will limit the constraints on the population and economic activity. The scientific council recommends a continuation of containment measure and in particular of the schoolchildren whom it would like to deprive of school until September, but is it justified?
To counter the hypothesis of a climatic factor on the spread of the virus, some argue that there are cases of Covid-19 in hot countries. This is true, but first you have to take into account the imported patients, then you have to see what the actual contamination figures are. However, the numbers of infected people and of deaths are very limited in the countries of the South. In a tribune of Echoes dated April 21, Professor Mehdi Mejdoubi (Valenciennes hospital center) demonstrates that hot countries have only a very weak spread of the disease “Below the Tropic of Cancer, the epidemic does not explode: 5,000 deaths for 4 billion people”. That is, for more than half of humanity, the current risks are limited. Professor Jean-François Toussaint explained, on April 24 on LCI, that 90% of the cases on Earth are included in a zone between 20 ° N and 50 ° N, a band which goes from North Africa (where it is relatively cold in winter), to the south of Norway (where there is a humid cold tempered by the Gulfstream).
The climate of the cities of Wuhan, Tehran, Bergamo, Mulhouse and Herbin at the time when the contamination explodes shows temperatures between 0 and 10 ° C with a relative humidity of 43% to 78%. The low sunshine and the presence of cold fog are notable in these regions. Particulate pollution (PM factor 2.5> 75) could be an aggravating factor because the particles could be a vector of the virus. Pollution times at a high level are a concern for Wuhan, Tehran, Bergamo and Herbin. But this factor does not seem to be decisive for Madrid and Mulhouse, with only 2 days of poor air quality polluted with fine particles in the reference month.
In the southern hemisphere, entering southern Australia in July could be critical for some cities, such as La Paz in Bolivia.
In April, a second wave of contamination was expected in China. Where does it happen? Not in cities where the temperature has already risen above 15 ° C, but in the northern city of Herbin. Herbin is known for its magical festival of giant ice sculptures in January. During this month, there were no sick people in Herbin. On the other hand, since the temperature rises towards the values of our other test cities (between 0 and 10 ° C), the contamination spreads.
The cold air weakens the immune defenses of the nose and allows the introduction of the virus into the respiratory system via droplets of saliva for example. But, if it’s too cold (below 0 ° C), the droplets freeze killing the virus. If it is hot (above 15 ° C), the droplets dry faster and the immune system of the nose provides an effective barrier because it is not “asleep” by the cold. The rate of UV radiation linked to the sun is also a factor favoring the rapid sterilization of surfaces contaminated by the virus as shown in the study led by Bill Bryan for the United States Department of Homeland Security.
The next virus targets in May could be the Siberian cities north of Herbin and some cities in Canada. In the southern hemisphere, entering southern Australia in July could be critical for some cities. A city like La Paz in Bolivia will then be in the critical temperature zone even if the winter is rather dry in this city. We will have to see if the humidity parameter is a major parameter like temperature.
My conclusion is that in May, in France, the temperatures will protect us from an epidemic recovery. Surely there will still be sick people mainly in people with weakened immune systems. Critical temperatures for epidemic spread will return to France from the north and east in November and especially in December. Mask stocks which should be received in May / June will then be very useful. On the other hand, the coupling between the analysis of climatic data and the location of the virulence of the contamination shows that we should have a flu-free summer. It is high time to restore freedom of movement and action to the French
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