We are currently experiencing, at global level, a historic moment as a result of the COVID-19 Pandemic.
COVID-19 is the infection provoked by the Sars-CoV-2, one of the seven human coronaviruses, and was initially considered an outbreak, that is, when there is an increase in cases of disease in a defined area or in a specific group of people, in a given period.
The first cases of this disease were reported on the last day of December 2019 in the city of Wuhan, the capital and largest city in the province of Hubei, in the People's Republic of China.
A month later, on 30 January this year, the World Health Organization (WHO) declared that this outbreak constitutes a Public Health Emergency of International Importance.
Although COVID-19 had already spread to five continents, WHO only considered it as a Pandemic on 11 March 2020.
At the moment, in global terms, the number of cases is around 417,663 infected, 108,312 recovered and 18,605 registered deaths, of which 6,167 occurred in five countries: China, Italy, Iran, Spain and France. At the moment, in Italy, the number of victims caused by this pandemic is higher than the number in the country where it first broke out.
In Portugal, the first two suspected cases were confirmed on 2 March. The virus that initially manifested itself in the north, spread quickly across the country, including the islands of the Azores and Madeira. The number of infected people has been increasing exponentially. As of 24 March, there have been more than 2,360 cases, of which 22 have recovered and 33 have died.
On 18 March, Prime Minister António Costa announced some measures decided in the Council of Ministers regarding the state of emergency in Portugal due to the Covid-19 Pandemic.
The measures enacted impose several conditions and how they will be inspected by the security forces:
- Citizens must fulfill a “general duty to remain at home”, especially people from high-risk groups (over 70 years old and the chronically ill), who can only go out in “exceptional situations”. Infected patients and people under observation are required to be confined;
- Closure of several commercial establishments, with the exception of take-away restaurants, bakeries, supermarkets, pharmacies, and petrol stations;
- Public services must operate via telework, use the telephone or online platforms for service purposes. Face-to-face service requires prior appointment.
Often, the outbreak of diseases gives rise to epidemics and rarely reaches the scale of Pandemics, whose designation causes panic in people.
The term epidemic comes from the fusion of the Greek word epi, which means "about" and demos which means "people", that is, something that spills over the population causing alarm and fear.
From a clinical point of view, an epidemic is a sudden number of patients suffering from the same disease without distinction of sex, age, race or social class.
Pandemic is considered to be the worst-case scenario for human health. Etymologically of Greek origin, the word Pandemic is the union of the words pan, which means "everything or all", and demos, which means "people".
Pandemic occurs when the disease (already in the epidemic phase) is widespread among individuals located in the most diverse geographic regions, such as in a continent or even in our entire planet. In these cases, there is an intercontinental epidemic contagion, of gigantic lethal proportions, capable of causing profound demographic, political and economic changes.
As for more recent years, in 2009 we had the example when Influenza A moved from Epidemic to Pandemic, after the WHO confirmed the existence of cases of this disease in all six continents, as well as AIDS, although, in the case of the latter, the number of occurrences is decreasing worldwide.
However, some historians have found that since the earliest times there have been several cases of epidemics and pandemics all over the planet, causing very high numbers of victims and with harmful consequences in social, economic or political terms.
In antiquity, the largest pandemic we know of occurred between 430 to 427 B.C. during the Peloponnesian War. Called the Plague of Athens or the Plague of Egypt, it killed two thirds of the population of that Greek city. Although it is still unknown today what type of disease it was, it is believed to have been an epidemic of typhoid fever (caused by the bacteria 'Salmonella tiphi'). At the time, doctors were powerless in the face of ignorance of the nature of the disease.
In 165 BC, the Antonine Plague, also known as the Plague of Galen, emerged. It lasted until 180 B.C. It is thought that it was an outbreak of smallpox or measles that initially affected the Huns and ended up spreading throughout the Roman Empire. Although the death of the Roman emperor Marco Aurélio was attributed to natural causes, it is presumed, however, that he was affected by this disease.
Fig.2 - Plague of Athens
Fig.3 - Antonine Plague
In 250 BC, the Cyprian Plague appeared, a name attributed in recognition of the Bishop of Carthage. Of unknown origin, it is estimated that it started in Ethiopia and spread throughout North Africa, went through Egypt and eventually reached Rome. In Alexandria, 60% of its inhabitants died. In the year 444, it reached Great Britain, forcing the weakened Britons to seek the help of the Saxons to fight the Scots and the Picts.
Despite being called "plague", the symptoms described are not identical to those of the bubonic plague. We must consider that in ancient times the term “plague” was synonymous with contagious disease and high mortality.
Even today, the virus responsible for the "Cyprian plague" is an enigma. For some historians, it may have been a viral haemorrhagic fever, for others it may have been a flu caused by a virus identical to the one that caused the Spanish Flu in 1918.
Justinian's plague broke out between 541 and 750 AD. It was considered the first historically documented pandemic and the first case of bubonic plague that killed approximately 50 million people, that is, about 26% of the world population and more than half of the European population. Originally from Egypt, it was generalized in the Byzantine Empire (when Emperor Justinian I “the Great” ruled), reaching as far as the Mediterranean.
Fig.4 - Cyprian plague
Fig.5 - Justinian's plague
During the 11th century, Europe was plagued by Leprosy, also known as Hansen's Disease. In the Middle Ages, this disease was seen as a punishment from God and it was believed that the sick had been cursed. Even today, Leprosy affects a large number of people around the world. As a bacteriological disease, it is possible to cure it when detected in its initial stages.
The Black Death, considered the greatest pandemic in the history of civilization, started in 1347 in Central Asia. It devastated Europe (as a result of the lack of sanitation) and was responsible for decimating between one third (25 million) and half of the population (75 million). This global bubonic plague epidemic was truly devastating.
As a consequence of the colonization of some countries by many more developed ones, some diseases that were non-existent in areas of some continents evolved into major pandemics, such as smallpox and measles. This was attested by the so-called Columbian Interchange. In 1496, when Christopher Columbus arrived in America, the Tainos (indigenous people of the Caribbean) were around 60,000 and in 1548, they were less than 500. Diseases like measles and bubonic plague killed about 90% of the population. The Aztec empire, for example, was destroyed by an outbreak of smallpox.
In 1665, the city of London was plagued by the bubonic plague, known as the Great Plague of London, which killed about 20% of its population. The following year, Londoners were still recovering from the Great Plague when they were struck by another tragedy - the Great London Fire.
The first news of pandemics was originated by the influenza virus in 1580 in Asia. In just 6 months, it spread to Europe, Africa and later to North America, killing about 10% of the population in the areas affected by the disease.
Later, in 1729, in Russia, the Flu returned and become a pandemic. In 1732, it spread across the world, killing about 500,000 people in 36 months. Other cases of pandemics occurred in 1781 in China, infecting Europe within 8 months. In 1830, a new influenza pandemic that also started in China passed through Asia, Europe and the Americas, where it infected about 25% of the population.
After these, pandemics began to have their own name. In addition to the flu, other diseases originated major pandemics, such as cholera, which resulted in 8 major pandemics that took over the entire world:
- In 1817 the cholera pandemic appeared, the first of eight, over the next 150 years. It is thought to have started in India, then spreading to China, the Republic of Azerbaijan, Kazakhstan, Turkmenistan and Russia via the Caspian Sea. It later spread worldwide, killing around 150,000 people;
- In 1832, cholera started in Europe, spreading to the United States, Canada and England;
- In 1852, the third cholera pandemic broke out, probably the most devastating ever. It severely affected Russia, causing more than one million deaths;
- Between 1863 and 1875, it expanded rapidly among the European and African population;
- North America suffered heavy contamination in 1866;
- In 1892, it mainly infected Germany, causing more than 8,000 deaths in the country;
- In 1899, it reached Russia, but with the advancement of Public Health, Europe was hardly affected;
- In 1961, flu broke out in Indonesia, spreading to Bangladesh, India, reaching the Soviet Union in 1966.
The wave of the third Bubonic Plague Pandemic began in 1855. It started in China and rapidly spread across India, then reaching Hong Kong. It is estimated to have claimed 15 million victims and that this outbreak was not extinguished until 1960.
In 1875, the Measles Pandemic broke out in the Fiji Islands. At that time these islands were colonies of the British Empire, whose chief was Ratu Cakobau. After his return from a trip to Australia where there was a measles epidemic, he ended up being infected and spreading this disease, causing the death of 40,000 people, a third of the islands’ population.
The Russian Flu started in 1889. The pandemic began in in Siberia and Kazakhstan and then spread to Europe, North America and Africa. The following year, in 1890, the Russian Flu had already claimed about 360,000 victims.
In 1918, the Spanish Flu broke out. The geographic origin of this influenza pandemic that plagued the world between 1918-1919 is effectively unknown. Although not of Spanish origin, it became known as Spanish flu, pneumonic flu, pneumonic plague or, simply, pneumonic.
This pandemic was called "Spanish Flu" because it broke out when the First World War was at its peak. The great world powers were involved in this conflict. On one side stood the allies (headed by the United Kingdom, France and the Russian Empire), on the other were the Central Empires (Germany and Austria-Hungary) and the United States. The latter tried to avoid the spreading of any information about the scope of the disease at all costs, in order to avoid discouraging the population with the news of an alarming number of civilians falling ill and dying in many places.
Fig.10 - Spanish Flu
Fig.11 - Improvised hospital during the Spanish flu
Spain, as a neutral country, had no need to hide this information and reported "the completely erroneous impression" that the country had been the most punished or that the disease had started there.
The first news about the disease appeared on 22May 1918 in the Spanish newspaper El Sol.
There are several assumptions as to where this “bird flu” strain will have started. For some historians, this pandemic started in and spread from a military camp in Kansas (United States of America) among the military who later travelled to Europe. For others, it started at the military base of Etables, in the north of France or among the Indochinese soldiers who fought in France between 1916 and 1918.
The enormous development of the disease was a consequence of the war at that time because the concentration of millions of soldiers created the ideal conditions for the development of more aggressive strains of viruses, which facilitated their spread throughout the world.
One third of the world's population was infected with this virus and it was the infectious disease that caused the greatest number of victims. It lasted about a year and contributed to about 50 to 100 million deaths worldwide, which represented up to about 5% of the world population, of which between 50 thousand to 70 thousand in Portugal, between the years 1918 and 1919.
The Spanish flu is considered to be the largest worldwide pandemic known to date, having caused more deaths than the Black Death in several countries, almost three times more than the number of people killed in the First World War. About 500 million people were infected with this flu, which killed more people in 25 weeks than AIDS in 25 years.
The “Spanish Flu” virus was 25 times deadlier when compared to other identical viruses. One of its characteristics was its high mortality among people aged between 20 and 40 years.
The first cases of Pneumonic in Portugal occurred in May 1918 and for two years it decimated tens of thousands of people. Some parts of the country lost 10% of its population.
The fight against the disease, led by Ricardo Jorge, then General Director of Health, included the closure of schools and the ban on fairs and pilgrimages. Dozens of public spaces functioned as wards for assistance to the sick. However, the number of victims was so great that over several weeks situations of real chaos were experienced. Two advices suggested at the time to the population in order to avoid contagion were: washing their hands frequently and covering mouth and nose when sneezing.
The Asian Flu broke out in February 1957 and was one of the world's largest influenza epidemics. It started in Northern China, where the virus spread rapidly, reaching Singapore and Hong Kong in about two months, then extending to other parts of the globe, such as the Australian continent, India, Africa, Europe, the United States, and in about 10 months it spread to all countries. In Portugal, the flu started on 7 August, through the arrival of passengers from Africa on the ship Mozambique, where the epidemic was felt intensely. This pandemic killed 1.1 million people worldwide. The rapid passage between the African continent and Europe was due to the existence of a high flow of people between both points, as a result of, at that time, there were a large number of European colonies in several African countries.
In 1968, the Hong Kong Flu emerged. In July of that year the first case of influenza started in that city. It made a big impact on the Vietnam War when it was taken to the United States and then spread rapidly throughout the world. Three months later, the virus had reached Europe, India, Australia and the Philippines. Worldwide, this pandemic killed about one million people, including half a million Hong Kong residents, which constituted 15% of its population.
In 1981, HIV/AIDS emerged. The spread of this virus exploded in the US in the early 1980s. Its origin has been identified in chimpanzees in Africa. Over 35 million people died of AIDS-related illnesses. Despite advances in medicine that allow patients to manage the disease, a cure has not yet been found.
In 2009, the Pandemic Influenza (initially called swine flu) started, which was labelled Influenza A in April of that year. At first it was an outbreak of a swine flu variant whose first cases occurred in Mexico in March 2009, shortly after reaching the European continent and Oceania.
This influenza pandemic caused by the H1N1 virus caused the death of 203 thousand people worldwide due to respiratory problems, mainly affecting the youngest people (between 5 and 24 years old) and the populations of some regions of the American continent.
Studies indicated that the number of deaths was almost 20 times higher in countries like Argentina, Brazil and Mexico, while the least affected countries were New Zealand, Australia and much of Europe.
Currently, we are much better prepared to face a new pandemic, through vaccination programmes and campaigns, and due to the progress made in the last century in communication technologies, which allow the world to react much faster to the threat of a planetary pandemic.
We currently have new resources at our disposal, such as smart thermometers connected to the Internet, whose measurements allow the detection of the beginning of an epidemic anywhere in the world, computer simulations that can help to predict the spread of infection by a virus and numerous drugs.
However, in the interconnected world in which we live, a virus can spread more easily. We may be surprised by the resistance of viruses to available therapies and viruses can mutate within a type, creating new variants that infect other species, including human beings, making it necessary to come up with new drugs capable of destroying them as quickly as possible.
There are currently other diseases such as Ebola, Zika, Dengue and Chikungunya, which are pathologies of worldwide concern. Due to their huge possibility of contamination, they can cause great pandemics and are therefore being studied intensively by the scientific community.
Some researchers, scientists and infectious disease specialist David Quammen say that once the coronavirus is under control, the world needs to start preparing for a next pandemic, because new pandemic outbreaks will emerge sooner or later. Whereas many environmentalists believe that the increased risk of catching new viruses is due to the increase in population worldwide, the National Geographic Campaign for Nature also states that there will be more diseases like Covid-19 in the future as a result of several factors, such as continued deforestation and the conversion of wild animals into pets, food or medicine. Meanwhile, the People's Republic of China has already banned the consumption of wild animals.
Many researchers stress the importance of taking urgent action and creating new regulations in order to protect our planet.
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