The sunset on Saturday 15 February, here in Milan on the last weekend before the coronavirus, remains among the most photographed in the memories of our mobile phones: a huge sun, purple like the star of an unexplored planet, sank its disturbing light behind the new ones metropolis skyscrapers.
Nothing will be the same as before in Lombardy. Covid-19 deaths in the region have now far exceeded 3,245 deaths (officially) recorded in China during the outbreak. And after more than a month from the beginning of the Italian emergency, while Beijing sends forty thousand doctors and nurses home and prepares to reopen the city of Wuhan, in our hospitals it is increasingly difficult to guarantee the stocks of adequate masks and protections for frontline staff. To the anger that is rampant in the wards, there is the pressure of those who, interpreting the latest data on hospitalizations and serious cases, would like to reduce the blockade and breathe the economy. Faced with the risk of hasty choices, it is worth returning to that week of February only apparently without viruses. And examine what happened: from the flow of Lombard commuters to serious atmospheric pollution, which has poisoned the Po Valley during the past winter. Two favorable conditions, which may have contributed to the faster spread compared to the rest of Italy and Europe.
The current maps of the epidemic expansion in Lombardy and around Milan are in fact superimposable on the maps that for years have described the crowding of public transport in the region. It is as if the Sars-Cov-2 virus, since its arrival in Northern Italy, had taken the green metro daily to Cologno Monzese and the eastern municipalities of the province, or the red line to Sesto San Giovanni, or the yellow line to Comasina and the suburban buses to Bresso, all places that after Milan are at the top of the contagion ranking. But the infections also moved by train to and from Lodi and Codogno, Cremona, Bergamo and Brescia, which are not by chance the most affected provinces. Obviously viruses do not walk alone but with the legs of people who penetrate, thus creating new outbreaks based on the local conditions they encounter.
Until the closure of schools and universities (February 24), the epidemic was therefore able to feed easily among a population of five million two hundred and fifty thousand commuters. There are many Lombards out of ten million inhabitants who in a normal period move for work or study or other reasons every day: one million 656 thousand in the metropolitan city of Milan, which are added to the commuters of the provinces of Brescia (663 thousand), Bergamo (597 thousand), Monza and Brianza (466 thousand), Pavia (274 thousand), Mantua (212 thousand), Cremona (186 thousand), Lecco (184 thousand) and Lodi (123 thousand). They are all districts that today have more than a thousand cases of Covid-19. Como, Varese and Sondrio are the provinces with the least contagions.
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Displacement conditions have not improved, even after February 21 and the discovery of the Codogno outbreak. Despite the current drop of up to 80 percent of passengers, transport companies have reduced journeys by up to 40-60 percent compared to normal weekdays, under the directive of the Region. The result ended up in the local news: amid cuts and cancellations, thousands of employees in the supply chains who cannot close or remotely transfer their work had to get on dangerously crowded trains, trams and buses still in the second week of March. A further favor to the epidemic, given that even those who are forced to move do not find masks to protect themselves.
What probably happened between January and February on public transport in Lombardy is indirectly explained by research published on March 17 by a group of American scientists in the “New England Journal of Medicine” in Boston: the Sars-Cov-2 virus survived as an aerosol in the air “during the duration of our experiment (three hours)”, with an 84% reduction in the viral count. While it was detected alive after 72 hours on plastic and 48 hours on stainless steel, albeit with a sharp reduction in the viral count of 99.9 percent. The same study also demonstrates the survival of the virus on cardboard for up to 24 hours. “Our result,” explains Neeltje van Doremalen of the National Institute of Allergy and Infectious Diseases of the United States, “indicates that airborne transmission and contact with materials is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces for days ». Wuhan's experience teaches that in the closed environment of subways and crowded trains the risk of contagion increases by sixty percent.
In early February nobody in Lombardy can suspect that the virus is probably already spreading on public transport and from here in daily life: rather than in the workplace, where contacts are not always close, it spreads slowly in the family, in the body of body of some sports in leisure and public places such as shopping malls, bars and restaurants. On February 6, however, a random event forces hundreds of thousands of commuters to go even closer and for several days on trains and at stations. They all travel along the southern route of Milan between Piacenza, Codogno, Lodi towards the metropolitan city: the same area as the first outbreak. That morning in Ospedaletto Lodigiano the Frecciarossa derailed just left from Central Station.
But the virus does not only meet policemen, railway workers and rescuers who accompany the injured to hospitals in the area. The high-speed line is closed and from February 6, for days, trains to and from Rome are diverted on the old railway. Many regional trains are thus canceled and commuters are forced to pile on those that remain.
The coincidence with the territories of the first outbreak does not seem accidental. An acceleration to the epidemic that still marks the difference between Lombardy and the neighboring regions of Piedmont and Veneto. But also between the heavily affected province of Piacenza and the rest of Emilia Romagna. “It is a hypothesis that we will investigate from an epidemiological point of view. Not only lifestyles, even casual episodes are crucial in the outbreak of an epidemic, “explains a general practitioner in the area:” In Lombardy, the infection was probably spreading at the same rate as the other northern regions. At one point, the Frecciarossa accident forced thousands of commuters to the same spaces. And for this reason only there has been an acceleration of cases who discovered the first patient. At that point, the spread of tampons to other Lombard provinces, such as Cremona and Bergamo, revealed what had been incubating for days ».
The fiery horizons, such as the afternoon of February 15, are an indication of another condition that probably favored the virus more in Lombardy than elsewhere. January and February gave spectacular sunsets. But the intense colors of the atmosphere are also a symptom of a high rate of pollution. Constant high pressure, thermal inversion and total absence of wind for weeks: last winter the air was so unbreathable that many Lombard sports teams suspended training or transferred them indoors. For several days the concentration of PM10, the particulate material with a size of less than 10 thousandths of a millimeter that penetrates our lungs, reached 80-100 micrograms per cubic meter of air in many units of the Po Valley, up to double the limit by law. Hazardous levels also for PM2.5 and nitrogen dioxide, derived from the gases emitted by heating systems and traffic.
The close relationship between virus and pollution has been proven for years. And it has been remembered in these days by a report of the Italian Society of environmental medicine. “Atmospheric particulate matter is known to act as a transport vector for many chemical and biological contaminants, including viruses,” says Leonardo Setti, a researcher at the University of Bologna who signed the document with colleagues from Bari, Trieste and Milan: “I viruses cling, with a coagulation process, to atmospheric particulate matter, consisting of solid and liquid particles capable of remaining in the atmosphere “. Obviously the contagion between people is much more probable and for this reason at the moment all that remains is to remain still. But the relationship between pollution and viruses will have to be taken into account until the Covid-19 epidemic is eradicated.
Already in 2010, the Chinese universities of Beijing and Lenzhou demonstrated the close correlation between particulate matter, weather conditions and daily measles cases in the period between 2005 and 2009. Scientists calculated the infections triggered by individual pollutants, the percentage of increase of cases and the relative delay in days. A 2008 American study, entitled “Air pollution end respiratory viral infection” and signed by Jonathan Ciencewicki and Ilona Jaspers of the University of North Carolina, could instead help to understand how the virus that left Wuhan to conquer the respiratory tract uses pollutants such as particulates. , nitrogen dioxide and ozone, poisons with which Lombardy's air is rich. As well as that of the Chinese metropolis of eleven million inhabitants.
The researchers related weather conditions and hospitalizations.
A survey carried out in Rome for three years and published in 2001 is also cited: “The authors note that the same daily levels of nitrogen dioxide were significantly associated with hospitalizations for respiratory infections.” These are the percentages: from +4 percent for acute infections to +10.7 percent for asthma in children. American scientists also explain how the amount of virus needed to infect laboratory mice exposed to nitrogen dioxide is one hundred times less than mice that have breathed clean air: just two days of exposure for six hours a day were enough to obtain the result.
Particulate matter also opens up the body to viruses that cause respiratory infections. In 2004, it was shown that an increase in PM of 10 micrograms per cubic meter over the years resulted in an increased risk of mortality from pneumonia and flu. And as a peak of 60 micrograms per cubic meter, viral infections of the respiratory tract in children (laryngopharyngotracheitis) increase by 27 percent. Other research, cited in the 2008 study, then examined the effects of PM10 and PM2.5 on macrophages in our immune system and the consequent reduction in their response to infections. Even if not much is known about the relationship between Sars-Cov-2 and pollution, we must immediately think about the future: radical decisions will be needed so that the epidemic does not recur with the coming winter.