Climate change has also increased the likelihood of a plague outbreak. As the climate warms, the range of activities of animals that carry pathogens (such as mosquitoes) will also expand. Some diseases that were previously endemic in the tropics—such as Zika fever transmitted by Aedes aegypti—may become more widespread. There is also a terrible situation, that is, terrorists may deliberately spread a certain pathogen. And genetic modification technology can make these “biochemical weapons” more dangerous.
   For many years, public health experts have been warning us to be careful about the emergence of new infectious diseases. The mutation of the pathogen or the change of the host’s living environment may make certain types of diseases that are not easy to infect humans or not easy to spread among people become popular. Among them, infectious disease experts are most worried about the epidemic of viral infectious diseases. The pathogens that cause epidemics are mainly viruses and bacteria. Ebola hemorrhagic fever is a viral infectious disease, and the famous Black Death is caused by bacteria. Certain bacteria have super drug resistance, which can make small diseases that should not be feared become incurable. However, we still have many effective methods for bacteria. Many traditional antibiotics still have good effects, and many new antibacterial drugs are also under development. In contrast, viruses spread rapidly and mutate easily, but we know very little about them, and there are no particularly effective antiviral drugs. Since the beginning of the 21st century, all new infectious diseases are viral.
   The most alarming thing is the 2014 Ebola epidemic in West Africa. In this outbreak, not only the number of people infected was 50 times higher than before, but the Ebola virus spread to big cities for the first time, causing many Western countries to panic. The Ebola virus was originally a virus carried by bats, but its spread from person to person is actually quite slow. But even slower is the international response speed. When the Ebola virus “out of Africa” ​​and began to raging all over the world, many people did not realize the seriousness of the incident. When the epidemic worsened, countries took measures such as quarantine to stop its spread. By this time, the death toll had exceeded 11,000.
   Isolating patients to prevent the spread of the epidemic has been in place since the Black Death. In the 21st century, we are still using this ancient method to fight Ebola. Is there no better response? I’m afraid it really doesn’t. The Ebola virus was discovered as early as 1976 and has been raging in Africa for decades. However, as of today, we do not have any effective drugs or vaccines. Although some research teams have developed experimental drugs and vaccines, these research results cannot be transformed into products that can be used immediately in a short period of time. The development and testing cycle of vaccines and drugs is very long, usually several years or more. Moreover, most infectious disease drugs and vaccines are not standing drugs, and there is no market demand, so it is difficult to make a profit. Therefore, pharmaceutical companies would rather invest R&D resources in other more profitable fields than to develop these “life-saving drugs.”
   The global Ebola epidemic has not only caused a large number of casualties, but also exposed many loopholes in the world’s health security: from the fragile public health system to the slow international response to the disconnection between the research and development and production of infectious diseases. Too many problems need to be solved, because the next plague may come soon.
   So, how should we deal with the next plague that may happen at any time? The Ebola epidemic has taught humans a lesson. From this, we realized that the following three aspects need to be improved: rapid identification of pathogens, vigorous development of infectious disease vaccines and drugs, and establishment of a complete emergency response system.
   Genetic diagnosis:
   14-year-old American boy Joshua, a 14-year-old American boy who quickly identified the pathogen, ended his family trip in Puerto Rico. He had a high fever shortly after returning home and had an unbearable headache. The doctor believed that he contracted a certain infectious disease during the trip and screened him for a variety of infectious diseases. However, several months later, the doctor ruled out the possibility of more than 30 diseases such as tuberculosis and West Nile fever, but still did not know the cause of the boy. At this time, Joshua in the hospital bed was dying. With the last hope, Joshua’s doctor sent his blood and spinal fluid samples to the University of California, San Francisco (UCSF). There is a first-class genetic diagnostics research team, they are Joshua’s last hope.
   Genomic diagnosis of infectious diseases is a technology that uses gene sequences to identify pathogens. Professor Huayan Qiu of UCSF is an authority in this field. Professor Qiu and his team can compare patient blood samples with the DNA sequences of more than 8 million known pathogens in the database. In the 1980s, so much data processing might take several years, but now the newly developed software can analyze 10 million sequences in 30 minutes. In just 97 minutes, Professor Qiu’s team found the “suspect” in Joshua’s body, Leptospira santarosai, a rare disease found in the Caribbean. After finding the cause, the subsequent treatment process became very smooth. Joshua received basic antibiotic treatment and recovered after four weeks.
   Although Joshua’s example is special, it is not very rare. Clinically, up to 25% of pneumonia cases and up to 70% of meningitis and encephalitis cases are caused by unknown pathogens. Doctors are usually able to narrow the scope of the cause with limited screening in order to adopt effective treatment plans, but it is not always successful. Genetic diagnosis can detect all sequences in a patient’s blood sample and find any recorded pathogens. This is a leap in the quality of infectious disease screening.
   Vaccine – an essential weapon
   plague outbreak once, as Huo Liaoyuan. Therefore, for the plague, blocking its spread is more important than treating the disease itself. Vaccines are an important “weapon” against the plague.
   The mid-20th century was the golden age of vaccine research and development, and the polio vaccine was born at this time. However, the world’s pharmaceutical market is now worth up to US$1 trillion, and vaccines account for only 3% of it. Many infectious diseases that are not rare have no corresponding vaccines. Is it because our ability to develop and produce vaccines has declined? Of course not, this is because the production incentive mechanism of the pharmaceutical industry has changed.
   Most of the vaccines that defeated many infectious diseases in the 20th century were produced by state-owned enterprises. These companies produced vaccines for no profit, but only to meet the needs of the public. At that time, the production of vaccines was almost nonprofit. However, since the 1980s, everything has been privatized. Emerging pharmaceutical companies have sprung up, but most of them are smaller in scale. Although they have research and development capabilities, they do not have enough human and financial resources to complete a series of expensive and lengthy processes before the product goes to market-safety and effectiveness testing, establishment of production processes, and application for licenses. Only some large pharmaceutical companies have all the expertise, and it will cost about $1 billion to get a new vaccine on the market. However, vaccines for common diseases are hardly profitable, and there will be no companies producing vaccines against certain viruses that are only likely to be epidemic. As a result, many pharmaceutical companies gave up this thankless task and focused on the highly profitable chronic disease field.
   Without profit-driven, vaccine research and development and production often require support from the government and public welfare funds. Since the 1990s, new therapies for diseases in impoverished areas (such as meningococcal vaccines) are usually jointly developed by the government and some large pharmaceutical companies or charities. However, in recent years, this kind of cooperation between official and private institutions has weakened. In 2013, the research costs of new infectious diseases by governments and private institutions accounted for only 1.6% of all healthcare research and development costs (a total of US$195 billion), of which only one-fifth was private investment.