2024-01-10 20:45:06
Updated Wednesday, January 10, 2024 – 19:45
Around this time, four years ago, we were beginning to hear about a new virus that was causing strange cases of pneumonia in China. Most of them did not imagine then that this coronavirus, which they still did not even have a name, was going to turn everything upside down. He SARS-Cov-2 It forced us, remember, to lock ourselves at home and change our way of greeting, but also to reorganize health care in record time to face a sudden pandemic.
It will not be the last microbiological threat that humanity has to face. History is plagued by phenomena like Covid; of pathogens that have managed to cause a wave of infections and a long trail of deaths. It is important to take them into account, because from all of them we can learn new ways to protect ourselves and prepare ourselves for the next microbe that manages to cross our doorstep.
Microbiologist Ral Rivas remembers these famous germs in Historia de los microbios (Guadalmazán), a work that reviews the annals of microbiology and how germs have marked the future of humanity. The history of microbes, for better or worse, has been, is and will be linked to the history of humanity., to the survival of the planet, to the ups and downs of societies, to the uncontrolled sobs and the most captivating joys, but also to the construction of the future and the progress of the human being. Whether we like it or not, the history of microbes is our history, says the professor of Microbiology at the University of Salamanca.
From the past, Rivas emphasizes, we can draw many lessons. Like these pathogens are unpredictable. Many of the outbreaks that have later become epidemics or even pandemics have been caused by new microorganisms. It is estimated that 60% of human pathogens come from animals, that is, they are zoontic diseases. And 75% of the new diseases that are being produced, three out of every four new diseases, have this zoonotic origin, explains the microbiologist, who clarifies that today there is a confluence of factors, such as globalization, demographic changes or deforestation, which favor the emergence of new pathogens.
Like Covid, the misnamed Spanish Flu is a clear example of a zoonosis whose dimension reached exceptional proportions. The scope of the Spanish flu was extraordinary. It killed more people than World War I, which had 9.2 million combat deaths, and World War II, which had 15.9 million deaths. It claimed more lives than the Black Death of the Middle Ages in 100 years and claimed more souls in 24 weeks than AIDS did in its first 24 years, explains Rivas. The causative agent was an influenza virus subtype H1N1.
The 1918 flu pandemic revealed that infectious diseases were a problem that must be addressed at the population level. In the years since, many countries changed their public health strategy: on the one hand, they chose to adopt the concept of socialized medicine and, on the other, they strengthened surveillance and medical care systems, he explains.
The origin of the black plague
As was the case in 1918, wars have historically been an invaluable ally for epidemics, Rivas recalls.
For example, the starting point of the so-called over black, one of the most terrible in history, occurred in the siege of Caffa (present-day Feodosia, on the Crimean peninsula). Caffa was a hive of humans when the Tartars who were besieging the city, before abandoning the siege, decided to throw the rotting corpses of the dead soldiers into its interior. That perverse rain, gruesome and deadly, brought the plague to the city. And from there, with the survivors who fled to Genoa, Venice and other Christian areas, it spread throughout Europe.
Along with those who fled trying to avoid death, the disease caused by the bacteria Yersinia pestis advanced at an average speed of about four kilometers per day, and reached the Arctic Circle in 1350. If we think about it calmly, it was quite a progress. commendable, considering that it was a time in which means of transportation were very limited, Rivas points out. The epidemic killed between a quarter and a third of the European population, approximately 50 million people, in the seven years from 1346 to 1353. Until the 17th century, the presence of the plague was common in Western European societies.
And that threat was what made some sharpen their wits to protect themselves. Some governments decided to establish containment measures. For example, in 1377 Ragusa (now Dubrovnik) established that before entering the city, new arrivals had to spend 30 days in a restricted place on the nearby islands, in case symptoms of the Black Death appeared. The health authorities of Northern Italy followed suit by increasing the surveillance period by an additional 10 days and this gave rise to the practice known as quarantineexplains Rivas.
Quarantine began during the 14th century in an effort to protect coastal cities from plague epidemics and became a gold standard for continental Europe in several hundred years that followed, emphasizes Rivas, who recalls that the plague also produced socioeconomic changes. , health, cultural and religious that unleashed the fundamental factors that facilitated the establishment of the Renaissance.
Among other examples, the book also cites the lethal role played by microbes imported to America after the landing of Columbus, the case of Napoleon Bonaparte and the Haitian debacle in 1802 due to yellow fever, the success of the use of variolation in the 18th century or how a epidemia de clera that occurred in London in 1854 marked the beginning of epidemiological studies that are usually used to stop an escalation of infections.
After the outbreak, the English doctor John Snow He questioned the predominant theories about the transmission of the disease, which advocated its contagion through the air, and pointed out for the first time to water as a vehicle of transmission. Like a true detective, Snow studied the distribution of cases and found that houses that extracted water from the lower reaches of the Thames as it passed through London had a high incidence of cholera. He even made a map showing that the deaths clustered around a specific source, the Broad Street bomb. After much work to obtain evidence, the doctor managed to have the well disabled, which caused the outbreak to subside.
His work, along with that of the Reverend Henry Whitehead, led to the correction of attitudes towards sanitation and the country’s water supply.
Unfortunately, Rivas continues, cholera is today endemic in many areas of Africa, Asia and America, where sanitation infrastructure and access to clean drinking water remain deficient. Today, Snow’s map is considered pioneer in the use of the geographical method to study an epidemic. Therefore, he must undoubtedly be considered one of the founding fathers of modern epidemiology.
Although we tend to associate them only with negative aspects, with death and illness, in reality microorganisms also provide multiple benefits to our society, recalls the microbiologist. In fact, without microorganisms, life on the planet would not exist. We would not be there, there would be no plants, there would be no animals, there would be nothing. Microbes are the basis of the development of life and also constitute present and future solutions to problems that confront us and that are related, for example, to climate change, to the sustainability of the planet, to the search for new medicines or to the elimination of contamination. Microorganisms have the answers and they are waiting for us to discover them, explains Rivas. And he concludes: We can learn from what happened to them in the past and continue exploring their universe for the future.
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