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While scientists are still trying to shed light on the origins and causes of the paintings, it is noteworthy that these events occur in the midst of the covid-19 pandemic, a disease caused by a complete virus until early 2020. unknown.
And even before the coronavirus news prevailed, over the last decade we have seen serious problems with other viruses in Brazil and around the world, such as Ebola, Zika, dengue, chikungunya, yellow fever, and measles.
Are health crises the result of chance in sequence? Or does the context in which we live favor outbreaks, epidemics, and pandemics?
Experts interviewed by BBC News Brazil point out that the second hypothesis is likely: today, the world has a number of characteristics that make it even easier for the appearance (or resurgence) of infectious diseases.
And, as you will understand throughout the article, there are at least seven factors that help explain this whole scenario: the cross-border movement of people, the huge urbanization, climate change, the demand for animal protein, increased contact with wild areas, the rejection of vaccines and the lack of health and care professionals. .
Nowadays, it is very easy (and relatively cheap) to cross continents and oceans in a matter of hours.
Suppose you want to go to the town of Urasoe tomorrow, in the south of the Japanese island of Okinawa, 19,382 kilometers from São Paulo, the city on the map that is farthest from the capital, São Paulo.
It can be reached in 33 hours and 10 minutes, with stops in Dallas and Chicago, USA, and Tokyo and Okinawan, Japan.
In practical terms, this means that you can become infected with a virus in Brazil and, before you show any symptoms, you can literally be on the other side of the world.
According to World Bank data, in 1990, 1 billion people traveled by plane. In 2019, that number rose to 4.5 billion passengers, which is more than half of the world’s population.
On the one hand, the increase in cross-border mobility represents an opportunity for business, relationships and relationships with other cultures. On the other hand, it facilitates the transmission of infectious agents, and can further accelerate epidemics or even pandemics.
One example of this is zika, a virus that circulated in some Pacific islands and was brought to Brazil from 2014 to 2015, where it caused a serious public health problem, including the birth of children with microcephaly.
In recent weeks, by the way, the monkey tail was restricted to some parts of early Africa, almost simultaneously on two other continents, on each side of the Atlantic, when authorities in the United States, Portugal and Belgium announced the detection. the first cases in their territories. Again, this is related to global mobility.
The United Nations (UN) estimates that in 1950, two-thirds of the world’s population lived in rural areas.
According to the agency, this proportion will be reversed by 2050: in just over two decades, 66% of people will live in cities. And the hardest change is yet to come in Asia and Africa.
The big question, experts say, is that many of these new urban spaces are already in short supply in terms of infrastructure, public transportation, housing, basic sanitation and health care.
And this, in turn, creates the perfect conditions for the free growth and circulation of viruses and bacteria.
Discharging untreated sewage into streams and springs, for example, can be a source of serious gastrointestinal infections.
Accumulating garbage in vacant plots is an ideal environment for the proliferation of vectors such as the Aedes aegypti mosquito, dengue, zika and the emitter of chikungunja.
“We must also not forget that urban environments are good agglomerations, and we know how close contact, especially in small, poorly ventilated areas, facilitates the spread of pathogens,” added virologist Flavio da Fonseca, a professor at the Federal University of Mines. General.General.
The increase in the average temperature of the planet has many consequences for health.
The World Health Organization (WHO) estimates that between 2030 and 2050, climate change will be directly linked to an additional 250,000 deaths each year.
Among the causes of these deaths, the entity highlights the rise in infectious diseases such as malaria and dengue.
And this is because the mosquitoes that transmit these conditions reproduce in the heat and take advantage of the water reservoirs that appear during the rainy season.
Now, if there is a tendency for temperatures to rise from now on, this is a great opportunity for many vectors to gain spread and spread even more infectious agents.
“We now see the appearance of diseases that are common in tropical regions in subtropical areas. We already have cases of chikungunya and West Nile fever in southern Europe and dengue in Florida, USA,” says virologist Anderson F. Brito, a scientific researcher. All by the Institute of Health (ITpS).
Greater relationship with animals
Yet on this issue, the role that the destruction of nature reserves can play in the emergence of new diseases caused by viruses, bacteria and other pathogens cannot be ignored.
World Bank data show that in 1990, the world had a forest area of 41.2 million square kilometers. That number dropped to $ 39.9 million in 2016.
Do you think this is a small restriction? The area, which has been destroyed by more than 1.3 million square kilometers in just 26 years, is almost the equivalent of the entire Amazon (Brazil’s largest state) and exceeds the area of countries such as Peru, Colombia and South Africa.
From a health point of view, this also poses a great threat to human beings. This is because viruses are silent in nature, fulfilling endless cycles of replication within another living thing.
The progress of urban and agricultural businesses ends up destroying many of these nature reserves, which displaces animals and makes contact with humans possible. Viruses that only affected a first species can then “jump” into us, in a process known as spillage.
“And we have a very anthropocentric view of things. We believe that most pathogens affect the human population, in fact when most of these agents are found in nature and live in balance with their hosts,” added Fonseca, Brazil’s president. Virology Association.
“When we eliminate these habitats, the virus tends to look for an alternative. And who are the closest hosts? Us,” he continues.
“For the most part, this interaction leads to nothing. But there are cases in which the pathogen adapts well and begins to evolve especially for the human species, causing new diseases,” he said.
One of the most recent outbreaks of Ebola, for example, began in West Africa in 2014 and has occurred in regions where wood and mineral extraction has taken place. As a result of these activities, humans began to have more contact with animals in the region, including bats that carried this virus.
In a BBC News Brazil report published in October 2021, virologist and pathologist Paula Rodrigues de Almeida, a veterinary lecturer at Feevale University in Rio Grande do Sul, explained that new infections usually occur in so-called “interface sites”.
“These are degraded natural environments in which this exposure of the human species to new viruses occurs more frequently,” he teaches.
In this area, the growing demand for animal protein cannot be ignored: the Food and Agriculture Organization of the United Nations (FAO) estimates that global demand for beef slaughter will increase by 81% between 2000 and 2030. The same increase can be seen in other livestock. products such as milk (97% more), sheep (88%), pork (66%), poultry (170%) and eggs (70%).
The big problem is that these creations are not always limited to the most appropriate health conditions. Lack of rules and supervision means that in many countries these animals are kept in tight places, unhygienic or mixed with other species.
It’s all that an infectious agent needs to mutate, combine, and “jump” on people.
In the 2009 H1N1 pandemic in Mexico, research showed that the flu virus that caused all these problems was a mixture of four different strains: two pigs, one bird and one human.
And this is not an isolated example: During the twentieth century, humanity suffered from a number of influenza pandemics, such as the Spanish flu (1918), the Asian flu (1957) and the Hong Kong flu (1968). They arose from a mutation in viruses circulating among birds.
“All of this means that human health is not isolated and we need to think more and more about our connection to animal health and the environment,” Brito interpreted.
The sixth factor on the list is related to the growing difficulty in convincing the population of the importance of vaccination.
Due to the difficulty of producing and distributing doses, due to the impact of fake news on the subject, the fact is that vaccine coverage against many diseases is below what is desired.
In Brazil, too, which has always been seen as an example in immunization campaigns, the rate of protection against preventable diseases is falling year by year.
The polio vaccine, for example, was applied to 100% of Brazilians who were part of the campaign’s target audience in 2005.
After 15 years, this rate has dropped to 76%, which means that one in four children is not properly immunized against the disease, which can lead to paralysis and death.
And this paves the way for some diseases to recur: measles was removed from Brazil in 2016, returned with revenge in 2018, and has since caused major outbreaks.
Because vaccination coverage is below target, there is no guarantee that other infectious diseases, such as polio itself, will cause serious problems after decades of control.
“Vaccines are a victim of their success,” Fonseca said.
“People no longer see the serious consequences of many infectious diseases, such as polio or measles, on a daily basis. As a result, many began to give more importance to immunization,” he added.
Finally, it cannot be ruled out that the lack of basic health and care facilities in many places can make a small problem an outbreak, an epidemic or even a pandemic.
Care professionals are concerned with examining health records and noticing changes in the pattern, such as the abnormal rise in cases, hospitalizations, and deaths associated with a specific disease in a particular region of the country.
Based on this data, it is possible to take advantage of public policies that help to address the problem. It may be necessary to strengthen the vaccine in this area, or to control the entry and exit of the population for a period of time.
In this scenario, it is also essential to have a healthcare service that is able to care for, diagnose and care for patients in the best possible way.
The big question is that a large part of the world does not yet have that very structure. As a result, many diseases can easily be created and spread before they are noticed by national or international authorities.
That’s what happened to Zika in 2015. “Today, we know that it has been more than a year since Brazil began identifying the virus, and that these initial cases were not dengue, but a new disease,” Brito recalled.
The virologist noted that modern surveillance involves not only observing the growth of cases, but a complete technological structure that can genetically sequence samples and identify the agent that causes this condition.
“During the Covid-19 pandemic, the surveillance structure has improved in high- and middle-income countries, but not enough has been done in low-income countries,” he compared.
“And we need to understand that while we have blind spots in surveillance systems around the world, the whole world will continue to be in danger,” he concluded.