Chinese scientists on Friday announced a breakthrough in decoding the evolutionary pattern of the coronavirus, which caused the worldwide outbreak of severe acute respiratory syndrome (SARS) last year.  

Zhao Guoping, a noted researcher from the China National Human Genome Research Institute, said in Guangzhou Friday that an eight-month extensive study of the SARS coronavirus in south China revealed patterns in various phases of the virus evolution.

Molecular analysis of virus isolated from SARS patients in Guangdong Province and the Hong Kong Special Administrative Region (HKSAR) demonstrated the initial phase of the epidemic was characterized by quick amino acid changes in the virus and relatively low infectivity.

The middle phase of virus evolution was marked by the "super-spreader case" and a slower amino acid substitution rate and high infectivity. The last phase of the epidemic saw a relatively stable virus genome structure.

The study also indicated the mutation rate of the coronavirus is a third of that of the AIDS virus.

Scientists analyzed the genetic coding of 18 virus samples isolated from 24 SARS patients in Guangdong Province and the HKSAR and 11 coronavirus-infected biological samples.

After comparing the genetic coding with those of the existing 32 human SARS coronavirus and two coronavirus of civet cats, scientists had a clearer understanding of the molecular mutational patterns of SARS, shedding light on pre-emptive control strategies and the development of therapies and vaccines for the virus, according to experts.

More than 60 scientists from Guangdong, Shanghai, Beijing, Wuhan, Hong Kong and the United States, assembled by the Chinese SARS Molecular Epidemiology Consortium, agreed that effective monitoring and control of the newly emerged animal SARS coronavirus would contain the reappearance of last year's SARS outbreak.

The study is also widely expected to provide valuable reference for studies on other animal-sourced infectious diseases such as the bird flu.

The Jan. 29 issue of Science Magazine in the US published the latest outcome under the title The Evolution of SARS.

(Xinhua News Agency January 31, 2004)