From Ebola to SARS to the new crown: how can the outbreak end?

BEIJING, May 12 (Xinhua) — According tomedia reports, the new coronary epidemic affected the whole world at an alarming rate, scientists around the world have invested in the fight against the epidemic, a team of researchers at Fudan University in Shanghai has deposited the entire genome sequence of the new coronavirus into the “Genbank”. More than three months later, researchers sequenced 4,528 new coronavirus genomes and conducted more than 883 clinical trials of treatments and vaccines related to neo-coronary pneumonia.

It is not yet known how long it will take for these trials to yield effective results. Whether the risk outweighs the benefits with the delicate balance between efficacy and safety, we can only wait. Because of this, long-term solutions such as vaccination may take years to really implement.

The good news is that inadequate treatment does not prevent the outbreak from gradually calming down. Neither Ebola virus nor atypical pneumonia has a ready-made vaccine, but the outbreak is gradually disappearing through persistent public health strategies, including testing, isolation and long-term behavioral adaptation. Today, countries such as China and Singapore, which have fought the 2002 SARS outbreak, are recovering from the new corona outbreak at an exemplary rate. Countries with current high mortality rates, such as Sweden, Belgium and the United Kingdom, will have the opportunity to demonstrate their lessons when the next outbreak approaches. The same is true of the United States.

The first Case of Ebola was confirmed in 1976, when a patient with haemorrhagic symptoms arrived at the Yabuku Church Hospital in the Democratic Republic of the Congo today. Doctors took samples from patients and sent them to several European laboratories specializing in rare viruses. Without sequencing, it took scientists about five weeks to identify the pathogen that would cause the disease as a new member of filoviridae. The virus is many silky in shape and is a class of highly pathogenic viruses infected with vertebrates.

The first outbreak of the Ebola virus sickened 686 people in the Democratic Republic of the Congo and neighbouring Sudan, 453 of whom died, with the final fatality rate (the death toll compared to the number of cases, abbreviated as CFR) reaching 66 per cent. Despite the virus’s lethality, sociocultural means, including blockades, tracing of contacts, changes in funeral ceremonies and restrictions on eating game, have proved effective interventions in the long run.

It was not until 2014 that the exception was made. The Ebola virus has emerged in guinea, a small West African country where people have never been exposed to the virus before. The most recent outbreak occurred 13 years ago in Gabon, about 4,000 kilometres from Guinea. Over a two-year period, Ebola haemorrhagic fever spread from Guinea to Liberia and Sierra Leone, sickening more than 24,000 people and dying more than 10,000.

In the early stages of the 2014 Ebola outbreak, rural communities did not actively follow government instructions on how to care for the sick and the dead. To encourage behaviour change, Governments in West African countries have brought in sociocultural anthropologists to advise, and experts say that keeping rural people connected with their loved ones can facilitate their cooperation with governments. For example, the government encourages villages far from the capital to “send representatives to hospitals and attend funerals so that they can return to the community and tell stories about the bodies”. For villages that can’t afford to send representatives to the capital, public health officials have adopted a clever technical approach — using a tablet to record video messages of recovering patients and then pass them on to their families.

However, the magnitude of the Ebola outbreak in West Africa in 2014 was due to some systemic failures. In Sierra Leone, “the early major mistake was the release of information about the disease’s transmission through animals (weak causality) that had been apparent at the time of the emergence of community transmission”. In other words, although there have been cases of animal transmission – the virus from bat to humans – triggering epidemics, the main danger is that of other infectious individuals, not wild fowl. Eventually, under pressure from aid groups, the government revised the message to reflect the scientific consensus.

However, the change has shaken public confidence in the government and sparked discontent. The mismatch between information transmission and reality also reflects the current pandemic of new coronary pneumonia. Since the outbreak of the new coronavirus, health officials from governments have sent different messages. Initially, doubts were raised about whether the virus could spread from person to person, and the debate over the effectiveness of masks in preventing infection continues.

Despite all the confusing information, in general, most people adhere to the “home isolation” rule, which helps to smooth the infection curve. If the public is less trusting of government directives, the results could be disastrous, as in Liberia in 2014. At that time, following a two-week blockade announced by the Government, the Liberian army conducted house-to-house inspections to identify patients and collect bodies. It is a grim method that leads to the hiding of sick and dead people in their homes, with the fear that their loved ones will be buried without proper rituals, with the direct consequence of an alarming number of cases of activity and the unknowing degree of community transmission. In the end, however, the end criteria for Ebola haemorrhagic fever and SARS were the same. The World Health Organization announced that the outbreak was over when the incidence of new cases declined and eventually ceased to occur. By the same standard, the outbreak can be declared at the end of the 14-day quarantine period and no new cases of coronary pneumonia appear.

Even if we manage to stop the pandemic, the new coronapneumonia is still likely to make a comeback. Ebola haemorrhagic fever erupts every few years under the new route of zoonotic disease transmission. Given the spread of new coronary pneumonia and the possibility that the new coronavirus will produce infectious mutations, the new outbreak is likely to flare up again.

Pathogenicity and toxicity

From Ebola to SARS to the new crown: how can the outbreak end?

There are two factors that affect the final outcome of the outbreak of new coronary pneumonia: pathogenicity and toxicity. Pathogenicity is the ability of pathogens to cause disease in the host body, measured by R0 (the number of people per patient who can be transmitted), while toxicity is the damage that pathogens can cause, and the best measure is the fatality rate. Although the Ebola virus, the atypical pneumonia (SARS) virus and the neo-coronavirus are of the same level of pathogenicity, with cases of infectious disease situated between 1 and 3 per patient, there is a significant difference between the two coronaviruses and the virulence of the Ebola virus.

The fatality rate for Ebola virus infection is between 60 and 90 per cent. The difference in fatality rates is due to differences in infection dynamics between different strains of the virus. The main cause of the toxicity difference between the Ebola virus and sars virus is the tendency of the virus, i.e. the virus attacks the cells differently. The mechanism by which the Ebola virus enters the cells is not entirely clear, but researchers have confirmed that the virus prioritizes immune cells and epithelial cells. In other words, the Ebola virus first destroys the body’s defenses and then destroys the fragile tissues of the vascular system. Patients suffer from internal and external bleeding, the most common cause of death being low blood pressure due to severe water loss. However, neither the SARS virus nor the new coronavirus directly attacks the immune system. Instead, they enter the pulmonary epithelial cells through ace2 receptors, which also ensures a lower mortality rate.

Interestingly, for these two coronaviruses, they show a range of toxic differences, despite similar patterns of infection: the final fatality rate for SARS viruses is 10%, while the fatality rate for new coronaviruses is 1.4%. During the SARS outbreak of 2002 and in the current outbreak of new coronary pneumonia, the differences in toxicity reflected in national data may be related to different levels of health care.

Positive response is the best way

After the SARS outbreak in 2002, China launched a program to identify the new coronavirus, which alerted Chinese authorities to SARS-CoV-2 in November 2019. Singapore’s successful response can also be attributed to their understanding of the dangers of unknown viruses and the necessary measures to prevent the crisis from spiralling out of control. In West Africa, it also seems clear that preparation should be made.

The alarming number of cases of new coronary pneumonia suggests that it will take some time for the outbreak to end. Everyone must identify, isolate, and track and detect all close contacts. Countries that fail to act quickly and lead to an out-of-control number of diagnoses will pay the price of life and money. By modeling, Martin Eichenbaum, an economist at Northwestern University, and others have calculated that the cost of a shutdown in the United States is about $4.2 trillion a year, a cost that proactive countries will not face. A recent study published in the journal Science by Harvard University suggests that new coronaviruses may experience seasonal outbreaks in the future, meaning we need to re-establish our social distance. In other words, the initial hesitation will affect years. In the future, smarter segregation principles, which impose restrictions based on health status, may mitigate the effects of these measures.

Government “inaction” was initially thought to promote the creation of population immunity, i.e. the spread of the virus is interrupted once everyone is infected. This is because infection and vaccination both cause the same antibody-producing process and therefore do not require the development of a vaccine. The Bloomberg School of Public Health at Johns Hopkins University estimates that 70 percent of the population needs to be infected with the new coronavirus or vaccinated if people are to be immunized. The development of vaccines has been slow, so population immunity can only be achieved by directly infecting the virus, which means that many people will die. A study by St. Clara County at St. Clara University found that only 2.5 to 4.2 percent of the county’s population is currently infected with the new coronavirus. Gungahlin, Germany, is also a hot spot for the new coronary pneumonia outbreak, with studies showing a local infection rate of about 15 percent. The proportion is higher, but still well below the 70 per cent required for group immunization. Given the risks inherent in waiting for population immunization, our best hope remains the development of vaccines.

One big concern about developing effective vaccines is virus mutations. The principle of the vaccine is to train the immune system to recognize specific compound structures on the surface of the virus, i.e. antigens. Virus mutations threaten vaccine development because they can alter the shape of the antigen stoking, allowing pathogens to effectively evade immunomonitoring. So far, the new coronavirus has been slowly mutated, but only in the region most easily exposed by the immune system, the echinoid protein (Spike), has been found to have a mutation. This suggests that the virus’s genome should be stable enough to be used for vaccine development.

What we do know, however, is that the ebola virus was wiped out thanks to the cooperation of public health officials and community leaders; the SARS outbreak ended only after all cases were confirmed and isolated; and the 1918 Spanish flu suddenly disappeared after two long and deadly seasons.

The final outcome of the outbreak of new coronary pneumonia is unclear. Ultimately, it will depend on our patience and economic bottom line. With 26 million americans out of work and protests erupting, it seems that many would rather risk their lives than become insolvent. Smart controls after a shutdown may be the best way to get the economy back on track, while also providing security for those most at risk. From now on, “be alert” and “get prepared” will be the slogans of every day and the most effective way to prevent social and economic collapse. (Any day)

  Anastasia Bendebury and Michael Shilo DeLay, ph.d.m., who earned their ph.d.terms at Columbia University, co-founded the science communication organization Demystifying Science, which provides a clear explanation of the inner mechanisms of natural phenomena.