Middle East Respiratory Syndrome (MERS) is among the research topics in CAS Key Laboratory of Pathogenic Microbiology and Immunology. Significant progress on the origin and mechanism of coronavirus entry into cell hosts have been achieved by GAO Fu (George Fu Gao), YAN Jinghua, WANG Qihui, and SHI Yi, et al., and related works are published by Nature and Cell Host & Microbe. On May 30, 2015, YAN Jinghua, professor of Institute of Microbiology, Chinese Academy of Sciences (IMCAS) and SHI Yi, associate professor of CAS Beijing Institute of Life Science, were interviewed by China Science Daily and they commented on public-concerned issues of MERS from scientific aspects.

MERS Strikes yet the Public Needs No Panic

FENG Lifei, China Science Daily

Despite higher fatality rate, MERS is less infectious than SARS.

China had already launched active preparations before MERS occurred in China.

 Middle East Respiratory Syndrome (MERS), known as the ‘cousin’ of SARS, has attacked the China. According to the report from the National Health and Family Planning Commission (NHFPC) on May 29, the first case of imported MERS infection was confirmed in Huizhou, Guangdong Province, and the patient was from South Korea.

 As MERS strikes, what is the ability of human-to-human transmission? What is the situation of international control and prevention? What responses have been taken by China? With these publicly concerned questions, China Science Daily interviewed related scientists in this field.

Little Possibility of Wide Transmission

The MERS virus was first discovered in Middle East, 2012, and has drawn attentions from worldwide scientists. “We have predicted that MERS would come to China,” said by Research Fellow YAN Jinghua, IMCAS, when interviewed by China Science Daily. Unlike Ebola which is transmitted through direct contact, both MERS and SARS are transmitted through the air.

 “Currently, MERS is less infectious than SARS which could be transmitted even through sneezes.” YAN Jinghua said. MERS belongs to the same category of β-coronavirus and the C-subtype, just as SARS. After infection of MERS, there are similar clinical symptoms like fever, respiratory failure, and sometimes accompanied by kidney failure. Statistically, the fatality rate of MERS is much higher than that of SARS and reaches to 37% (the number released by the Chinese Center for Disease Control and Prevention is 27%). However, the transmission is limited.

According to open data from World Health Organization (WHO), up to mid-May, in three years the MERS virus has caused over 1100 cases in more than 20 countries around the world. YAN Jinghua said that currently there is no evidence to verify wide transmission of MERS among humans all over the world, and most cases are infected by animal-contact or close-contact in hospitals.

 Moreover, as a virulent virus, MERS has little possibility of wide transmission. “The more virulent a virus is, the more easily it dies out,” said by YAN Jinghua. If the host is killed, the virus will die out together.

Antibody research in progress

At present, the key issue with MERS virus research is the lack of suitable lab animal models. “The aye-ayes may be used as an infection model for MERS, but they are mainly pets, not general animal models like mice, which are difficult to be infected by MERS”, said by SHI Yi when interviewed by China Science Daily, “Currently, some scientists have transmitted the human CD26 receptor of MERS into mice, and generated an artificial animal model for MERS infection, however, this engineered mice may not suffer the same symptoms as humans.”

 Nevertheless, several advances have been achieved by Chinese scientists. The research team led by GAO Fu (George Fu Gao), CAS Academician and investigator in pathogenic microbiology and immunology, reported their findings in Nature 2013, which clarified the molecular mechanism of MERS entry into hosts.

 “There is an ‘S’ protein, named by spike protein, on the surface of MERS virus, which is in charge of the invasion of virus. This protein will bind to the human CD26 receptor through its RBD domain, and then the virus could invade the host cells.” SHI Yi explained to China Science Daily, who is one of the research fellows in GAO Fu’s team.

 In the recent two years, this team is developing therapeutic antibodies based on their previous research work. “The principle is to cover the MERS virus by therapeutic antibodies and block the viral invasion into host cells.” SHI Yi revealed that this antibody has been tested on mice and could effectively clean the virus.

 Besides, as a zoonotic disease, many scientists believed that dromedaries are the main hosts of MERS virus. GAO Fu’s team speculates that this virus may be originated from a bat coronavirus HKU4 and dromedaries are only intermediate hosts, and reported their work in Cell Host & Microbe 2014.

Precaution, Yes; Panic, No

Although MERS virus has limited transmission ability among humans, scientists are not sure whether the virus would mutate in the future to become more infectious. For this, YAN Jinghua said that once the virus in the Asian patients is isolated, it will be immediately analyzed, and results need further confirmation.

 Scientists believe that China needs precaution of MERS virus, but the public don’t have to scare. The Customs should strengthen monitoring of such virus, to prevent the importation of pathogenic virus carried by foreign passengers. Meanwhile, domestic research of prevention should also be well studied.

 “Different from the Ebola outbreak in Africa,” YAN Jinghua said, “after SARS, China has promoted progress in dealing with outbreak of infectious diseases, which is greatly superior to Africa.”

 Additionally, on dealing with outbreak of infectious disease, China has advanced medical equipment and sophisticated researchers as developed countries. In fact, China has been actively responding once the MERS virus was first discovered in Middle East.

 “CAS and NHFPC have launched a series of projects on development of vaccines, therapeutic antibodies and polypeptides, and chemical drugs for MERS. These projects can be performed quickly, since we have sophisticated experiences to fight against SARS.” SHI Yi said. Up to now, several therapeutic antibodies and polypeptides have been developed in China, and are effective in the laboratory investigation. Next, clinical trials need to be speeded up.

China Science Daily, Highlights, Front Page, June 1, 2015

Links: http://news.sciencenet.cn/htmlnews/2015/6/319968.shtm?id=319968