Is it possible for humans to eliminate viral infectious diseases in the future?

Is it possible for humans to eliminate viral infectious diseases in the future?  In the face of the COVID-19 epidemic,  world people feel quite frustrated.

On the one hand, a living body with such a small size and simple structure and function like the new coronavirus, once evolved the ability to invade the human world, may have a profound impact on the lifestyles, social patterns and even the world outlook that billions of people are accustomed to. , And even change the trajectory of the development of the human world.

On the other hand, although human science is advancing rapidly, the ability to understand new viruses and new infectious diseases is rapidly improving, and the dawn of drugs and vaccines can almost be seen in just one year, but it is clear that Compared with the spread of the virus, the human response speed is still not fast enough. For almost all of the time in 2020, the main means for humans to fight against the COVID-19 virus are still mandatory isolation, reduction of public activities, and wearing masks-the same as our ancestors’ actions against the Black Death and smallpox.

The 1918 flu, picture from wiki

And more importantly, we may be confident enough to say that mankind will eventually be able to figure out a way to restrain the COVID-19 virus, so that it can only “flee to commit crimes” at best, and cannot cause destructive interference to the human world. But from our discussion, you should also be able to see that there are still a large number of viruses that seriously threaten human security, ranging from influenza virus to HIV, from Ebola virus to Zika virus. What’s more terrible is that there are a large number of unknown viruses in nature. Humans do not know their existence, but they may suddenly evolve the ability to invade the human world at any time, stirring up the pandemic like the 1918 flu and the 2020 COVID-19 epidemic. Such a bloody wind.

With such a powerful, fast-spreading, and mysterious threat, can we humans really have an ultimate solution? In the foreseeable future, is it possible for mankind to eliminate viral infectious diseases?

You may give a very optimistic answer-and you have good reasons to do so. After all, we humans have a successful precedent in eliminating dangerous viruses.

In 1977, the last smallpox patient in human history appeared in Merka, Somalia. On October 25, 1979, two years after the patient—the herder Ali Mao Marin—healed, given that no new smallpox infection was found in the world for two years, the World Health Organization officially announced that human Eliminated smallpox.

This is the first disease ever eliminated by mankind, and it is precisely an infectious disease caused by a virus. So far, the smallpox virus has been extinct in nature for more than 40 years.

The eradication of smallpox is a war that has lasted for thousands of years. From the human pox vaccination in ancient China and India to the cowpox vaccination invented by the British doctor Edward Jenner, mankind actually had a powerful weapon against smallpox very early. However, if you want to completely eliminate a disease worldwide, you need not only medical technology, but also the deep mobilization and close cooperation of governments and people all over the world. After the establishment of the World Health Organization in 1948, the elimination of smallpox became one of the primary missions of this multinational organization. In the decades since then, the World Health Organization has carried out personnel training and public education in various countries, especially the vast majority of underdeveloped countries, to promote the universal vaccination of vaccinia, monitor new patients, and control the scope of the disease. Encirclement to this dangerous virus.

Polio, commonly known as “polio”, is not far from being completely eliminated by humans. By 2019, only Afghanistan and Pakistan still have new cases in the world, and the number of cases is less than 40. And polio is also an infectious disease caused by a virus.

These two cases really show that viral infectious diseases can indeed be eliminated. If countries around the world work together, through the development of vaccines, through close tracking of cases, and large-scale promotion of vaccination, they can indeed eliminate the once ravaged humans. Dangerous virus of the world.

At the same time, I have to regret to say that the successful cases of smallpox and polio are not so easy to replicate. It can even be said that their success is the result of many restrictive conditions being met at the same time. Other viral infectious diseases, including the new coronavirus and influenza virus, are not met.

Two particularly critical constraints are:

If a virus only spreads in the human world, it is relatively easy to be completely eliminated; and if it can spread in other animal species, then it is almost impossible for us to eliminate it.

Another key constraint is that the spread of this virus must be particularly “obvious”. Simply put, as long as a person is infected by the virus, they will show very strong and clear symptoms.

This principle is easy to understand. Smallpox and poliovirus are two viruses that only spread in the human world, and when they spread, they can cause serious disease symptoms, such as high fever, macula (smallpox), headache, vomiting, and stiff neck (poliomyelitis). Inflammation) and so on. Based on these characteristics, we can identify and track each patient and accurately cut off the transmission chain. After a period of time, the transmission chain of this virus will be cut off, and finally they can be eliminated from the human world. And because these two viruses can’t survive in organisms other than humans, once they are extinct from the human world, they will be completely wiped out.

On the contrary, influenza viruses and new coronaviruses do not meet these two restrictions, so it is almost impossible to completely eliminate them.

First of all, they all have animal reservoirs other than humans. Let’s take the flu virus as an example. In addition to infecting humans, it can also infect pigs, dogs, cats, horses, seals, and various wild and domestic birds. Even if we temporarily eliminate influenza viruses in the human world, they will continue to invade the human world from these natural hosts. And we obviously cannot eliminate all these animals. The new coronavirus is similar. Although we still don’t fully understand its transmission path and source, we already know that it can infect many kinds of animals including cats, dogs, minks, ferrets, and monkeys. In this way, it becomes impossible to completely eliminate the new coronavirus from nature.

At the same time, whether influenza virus or new coronavirus, their spread is quite “hidden.” Both viruses have an incubation period, that is to say, a person often has an incubation period of several days from the time a person is infected with the virus to show symptoms (influenza virus is generally 1 to 3 days, and the new coronavirus can be as long as 14 days or more) During this period of time, it is almost impossible for us to identify all virus-infected people and isolate them, which means that the trouble of virus transmission during the incubation period is difficult to eliminate. Like the new coronavirus, we also found a large number of so-called “asymptomatic infections”. These people may even get rid of the virus from being infected to the body. The whole process has no symptoms at all, but it is also contagious. Unlike viruses such as smallpox and polio, the characteristics of influenza viruses and new coronaviruses make it difficult to completely cut off their transmission chains.

Here we are discussing the existing viruses in the human world, which ones may be eliminated and which ones are impossible. The bigger problem is that there are still a large number of new viruses in nature, which are silently evolving the ability to invade humans in the dark, and are waiting to attack at any time.

In fact, let’s look at the virus pandemics that have occurred since the 21st century, the SARS epidemic in 2002-2003, the H1N1 influenza virus epidemic in 2009, the MERS epidemic in 2012, and the new coronavirus epidemic in 2019-2020. The real culprit behind viral infectious diseases was the first time that they entered the human world from animals in the 21st century, and they did not exist in humans before. Even the Ebola virus epidemic that broke out in West Africa from 2014 to 2016, the Zika virus epidemic that broke out in South America in 2016, and the HIV virus that has been circulating. These viruses entered the human world within the past 100 years.

In the future, we can almost certainly say that the new viruses hidden in the animal world will continue to look for the weakness of the human world and wait for opportunities to break through.

Picture from wiki

Some new coronaviruses discovered by scientists from pangolins are certainly not likely to be the ancestors of this new human coronavirus, but they are obviously very close to completing the animal-to-human species leap. In the core region of the viral genome, only a few genetic mutations are needed, and these viruses may have the ability to invade the human world in a short time.

Based on these discussions, I think it is certainly possible for humans to imitate the experience of smallpox and polio viruses and continue to eliminate some dangerous viruses. But if we want to say goodbye to the virus threat thoroughly and comprehensively, we currently do not have this strength. This is true for the new coronavirus, the same is true for the influenza virus, and so are more viruses.

Does that mean that we can only sit idly by and react passively in the face of potential threats from the virus world?

Of course not. I think humans still have a chance. Although it is unrealistic to completely wipe out the threat of viruses, there are still some ideas to greatly reduce the threat.

First of all, we may partially block close contact between animals and people, making it more difficult for new viruses to enter the human world.

I believe you have also seen that a large number of new human viruses come from animals. They have crossed the last barrier between species through genetic mutations and successfully landed on the large-scale human gu farm. However, this step cannot be done in a vacuum. We have actually discussed in the previous chapters what prerequisites are needed to complete this species leap.

Here may wish to repeat the main points:

Before entering the human world, the new coronavirus (also applicable to all possible new human viruses in the future) should be parasitic in a host animal. This animal should be a semi-wild mammal that can be farmed and transported on a large scale, and is closer to the human world. The reason here is actually very simple: in the semi-wild state, it can have more chances of contact with wild bats (also applicable to other wild animals) and can obtain viruses from them. The relatively large population size provides a platform for the mutual spread and mutation of viruses within this host. And only this kind of animal is relatively close to the human world, and has many opportunities to come into contact with people, which gives the new virus a selective pressure and finally allows it to infect the human body.

You see, considering these conditions, we want to reduce the chance of new viruses invading the human world in the future. One conceivable solution is, is it possible for us to stay away from animals altogether?

Please note that I am not talking about killing animals, especially wild animals. This idea is very ridiculous and dangerous. None of us can predict the possible consequences of arbitrarily destroying the earth’s ecosystem. On the contrary, what we can take immediately is to try to avoid invading the natural habitats of wild animals, so that they can maintain their natural living conditions as much as possible, and not have too much intersection with the human world.

On a longer time scale, we may be able to gradually reduce our dependence on poultry and livestock, and use other methods to produce meat and animal products, thereby reducing the risk of viruses in their bodies invading the human world.

In fact, there is a mainstream cognition in the scientific community that most viruses circulating in the human world today were obtained from animals after our ancestors entered the agricultural society and started raising poultry and livestock. Human ancestors and poultry and livestock get together day and night, providing opportunities for viruses to cross the species barrier and enter the human world. On the other hand, after entering the agricultural society, human ancestors obtained a rich and stable source of food, the population size was greatly increased, and a high-density population gathering area was formed, which allowed the virus to spread, evolve and evolve from person to person. Popularity provides a natural breeding ground.

This has even affected the political structure of the modern world. The famous scholar Jared Mason Diamond argued in his masterpiece “Guns, Germs, and Steel” that most animals that can be domesticated live on the Eurasian continent, while the Americas and Australia No animals are born to be domesticated. In this way, compared with the residents of other regions, the residents of Eurasian continent naturally have the foundation to start agricultural civilization. And this kind of civilized unfairness has also brought about the unfairness of the virus: the residents of Asia and Europe have been tortured by the virus invasion since 10,000 years ago, but they have also formed a certain degree of immunity to the virus. force. However, limited by the natural resources of the Americas and the Australian continent, the local indigenous people did not domesticate animals such as cattle, sheep, pigs, and chickens on a large scale, and they have no resistance to viruses from animals. Therefore, after Columbus discovered America, the number of Indians in North America decreased by 95% in just one or two hundred years. Of course, there were factors that European colonists consciously expelled and slaughtered, but the spread of smallpox played a devastating effect. In the face of this unprecedented virus, local residents can only wait to die. In South America, in Australia, similar scenes are also being staged. We can even say that it was with the help of the virus that European colonists easily occupied these vast and fertile lands and formed a situation of dominance over the entire world.

If we want to avoid a similar story from repeating itself, it might be a solution for humans to get rid of dependence on domestic animals. This is not entirely a fantasy. In the past few years, many start-up companies have been studying how to use plant protein to produce foods that are close to meat in taste and nutritional content. Some companies even simply research how to artificially cultivate animal muscle cells in the laboratory. Make “artificial meat”. If humans can really produce “artificial meat” that can meet the needs of most people, it will not only save a lot of resources and space for raising poultry and livestock, reduce greenhouse gas emissions, but also further keep humans away from the source of these viruses.

The above-discussed plan can be said to be to draw salaries from the bottom and reduce the threat of unknown viruses to humans. Let’s take a step back and say, if a virus invasion has already occurred, is it possible for us to respond faster and in a timely manner?

Earlier, we have talked about the “impossible balance” of epidemic prevention and control. If you want to quickly control the spread of an epidemic, the symptoms of the disease itself are mild, and the base of patients with the disease is huge. The two cannot appear at the same time. We cannot predict and control the natural symptoms of the disease, but the patient base can be reduced through efforts. This “impossible balance” essentially means that for a new infectious disease, it is the most critical to discover, isolate, track, and control the first time.

But when a disease first appears, it is precisely when the information is the most lacking and the most confusing, and it is the most difficult to take decisive measures. In the next chapter, we will discuss how we can do better in the areas of early detection, treatment, scientific communication, and international cooperation in the face of the next epidemic. Here we enlarge the scope of discussion a bit more to see if there are any new ideas to solve the problem.

The first idea is the genomics technology we have discussed several times. From the SARS and COVID-19 pneumonia outbreaks, we have seen a very difficult problem: in the face of a brand new infectious disease and pathogen that humans know nothing about, it is actually very difficult to quickly identify and respond. After all, front-line medical staff face a large number of patients with similar symptoms every day. It is a very difficult task to accurately identify new diseases from them, report them in time, and take public health measures.

If genome sequencing can be done very quickly, cheaply and accurately for patients’ disease samples, and genomic sequence information is used as one of the criteria for disease diagnosis, then it is possible for us to quickly discover the existence of new viruses and new diseases in the first time. In fact, in this COVID-19 epidemic, doctors have learned through genome sequencing and analysis that there is a new type of coronavirus in some patients. If this technology can be applied to the forefront of clinics on a large scale, it may buy us more time to fight infectious diseases. Perhaps in the future, genome sequencing of patient samples will become a necessary link in disease diagnosis, and even the first link for all patients to enter medical institutions. Of course, to achieve this, today’s genome sequencing technology is far from enough in terms of cost (at least several thousand yuan) or speed (at least a few days). A genome sequencing technology that can be used directly in the outpatient clinic of a hospital and obtain results in tens of minutes, and that ordinary people can withstand, will greatly change the understanding and countermeasures of new diseases.

In addition, there may be technologies based on mobile Internet that can change the situation.

Smart phones and mobile Internet have become the infrastructure of modern society. In this COVID-19 epidemic, some people did use the data provided by the mobile Internet to analyze the migration pattern of the population, and to mark patients in neighboring communities, and so on. But I believe that the information we can unearth from these data is much more than that. For example, can the movement trajectory of the smartphone help us find out who a patient had close contact with before the onset of illness? Is it necessary to take measures such as isolation? In a certain area and a certain period of time, the frequency of use of keywords such as “cough”, “fever”, and “diarrhea” on social networks. If there is a sudden fluctuation, does it indicate a certain infectious disease? In fashion? Even in the future, can smart phones integrate the measurement of certain human vital indicators, such as heart rate, body temperature, blood oxygen saturation, etc., to turn the entire mobile Internet into a public health institution? With the support of these data, our understanding of the overall health of the population will be more accurate and faster, and new situations that have just occurred in any place may be immediately identified. If this information is combined with genome sequencing technology, maybe we can really catch any new virus when it just enters the human world and hit it head-on. In this case, even if we cannot prevent the emergence of new viruses, we will certainly be able to greatly reduce the threat of new viruses.

Previously, we discussed nucleic acid vaccine technology. Of course, this technology still needs time to test, but once it is widely verified and accepted, it will completely rewrite the map of human vaccine development. The design and development of this type of vaccine is relatively straightforward (you can start designing with the viral gene sequence), and it is relatively easy to produce. If the virus mutates, it is convenient to change the vaccine nucleic acid sequence and re-vaccinate on a large scale. With this weapon, the speed of human response against new viral infectious diseases will be greatly improved. Following this line of thinking, in the future, humans may be able to develop vaccines and new drug systems based on nucleic acid sequences that can be quickly developed and produced. In a few months or even a few weeks, a medical plan to fight viral infections will be developed.

(source:internet, reference only)

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