Popular science: how "hunters" track the hepatitis C virus-interpretation of the 2020 Nobel Prize in Physiology or Medicine

　　Xinhua News Agency, Beijing, October 5 (Reporter Peng Qian) The history of human existence and development is also a "history of struggle" against viruses.

Hepatitis is one of the most serious health challenges that mankind has faced for a long time.

　　Fortunately, after several generations of scientists' explorations, mankind has figured out the "full picture" of several hepatitis viruses and developed effective prevention and treatment methods.

This year's Nobel Prize in Physiology or Medicine was awarded to three "virus hunters" who made outstanding contributions to the discovery of hepatitis C virus-Harvey Alt, Charles Rice and Michael Horton.

　　Hematogenous hepatitis has a high morbidity and a high fatality rate. It causes more than one million deaths worldwide every year. It can also cause liver cirrhosis and liver cancer, and bring more unbearable long-term illnesses to patients.

Although alcoholism, environmental toxins, and autoimmune system diseases can also cause hepatitis, the main cause is viral infection.

　　As early as the 1940s, scientists discovered two main types of viral hepatitis.

Among them, hepatitis A is mainly transmitted through contaminated water or food, and the course of the disease is more acute and has relatively little long-term impact on patients; while the other type of hepatitis is mainly transmitted through blood and body fluids, which can lead to chronic infections and eventually develop into cirrhosis and liver. Liver cancer is a more serious threat.

This type of chronic hepatitis is also particularly "cunning", it will quietly infect healthy people, and cause serious complications only after many years.

　　In the 1960s, American scientist Baruch Bloomberg discovered that hepatitis B virus causes the latter type of hematogenous hepatitis, and for this he won the 1976 Nobel Prize in Physiology or Medicine.

However, there seems to be a "missing puzzle" in the study of the pathogen of viral hepatitis.

At that time, Alt was studying patients with hepatitis through blood transfusion at the National Institutes of Health.

He made a worrying new discovery: After excluding hepatitis A virus and hepatitis B virus infection, there are still a large number of hepatitis cases. Does this mean that there are still unknown pathogens?

　　Alter and his colleagues further researched and found that these hepatitis patients can transmit the disease to chimpanzees, the only susceptible host outside of humans. This unknown pathogen also has viral characteristics.

They therefore defined this chronic viral hepatitis as "non-A, non-B" hepatitis.

This is also the main achievement for Alter being awarded the Nobel Prize this year.

　　Next, it is important to clearly identify this new type of hepatitis virus.

Scientists worked hard for 10 years, and the traditional virus "hunting" methods all ended in failure, until Horton successfully confirmed the existence of the new virus by analyzing the serum antibodies of the infected person.

Horton and colleagues discovered that this is a new type of ribonucleic acid (RNA) virus, named hepatitis C virus.

The related antibodies in patients with chronic hepatitis also indicate that this is the "missing puzzle" before.

　　The contribution of the third winner Rice is to answer another important question: Can the virus alone cause hepatitis?

To answer this question, scientists need to study whether the virus can replicate and cause disease.

Rice and colleagues suspect that an unknown region at the end of the hepatitis C virus genome may play an important role in virus replication.

Using genetic engineering technology, Rice created an RNA variant of the hepatitis C virus containing this unknown region and injected it into the chimpanzee liver.

Subsequently, the virus was detected in the chimpanzee's blood, and its pathological changes were similar to those of human chronic hepatitis patients.

　　So far, the "hunters" have found all the evidence that the hepatitis C virus causes blood-borne hepatitis.

　　The award committee said in a press release that day that thanks to the findings of the three winners, hepatitis C virus can now be detected through high-sensitivity blood tests, which has basically eliminated "post-transfusion hepatitis" in many places and greatly improved global health. .

Their discovery also accelerated the development of anti-hepatitis C virus drugs and cured hepatitis C for the first time in human history, bringing hope to the eradication of this chronic hepatitis in the world's population.

Of course, to achieve this ultimate goal, international cooperation is needed to promote blood testing and increase the availability of antiviral drugs worldwide.