Scientists have identified the stages in the evolution of
  the Sars virus that turned it from a simple animal infection
  into a lethal human disease.

  A study of the genes of more than 60 Sars viruses has found
  that it took just three major changes to the virus's genetic
  material to transform it into a highly effective killer of
  people.
 
  During the earliest phase of the epidemic the Sars virus
  infected about 3 per cent of those who came into direct
  contact with it, according to the study. Within a few months
  the proportion was 70 per cent.
 
  Chinese scientists, working with a team at the University of
  Chicago, analysed the Sars virus from the early, middle and
  later phases of the 2002-03 epidemic. The researchers found
  that the first phase of the epidemic involved a virus
  virtually identical to that found in wild animals but it
  mutated to cause a second phase, during which the virus spread
  from human to human.

  A final, third phase involved a further set of mutations that
  allowed the virus to stabilise and get accustomed to spreading
  still further within its new host species, said Chung-I Wu,
  professor of ecology and evolution at the University of Chicago.
  "What we see is the virus fine-tuning itself to enhance its
  access to a new host - humans. The virus improves itself under
  selective pressure, learning to spread from person to person,
  then sticking with the version that is most effective."

  The findings, published in the journal Science, confirmed that
  Sars was an animal disease that had jumped the "species barrier"
  into man. But the study did not determine which animal was the
  natural "reservoir" for the virus.
          
  The middle phase of the epidemic [was] an outbreak of about
  130 cases, including 106 patients who acquired the virus in
  hospital. A doctor at the hospital carried the virus to the
  Metropole Hotel in Hong Kong where the guests became infected
  and spread the virus across the world.

By Steve Connor, Science Editor
30 January 2004
http://news.independent.co.uk/world/science_medical/story.jsp?story=486003

  ---
  Also from The Independent
 
  Bird flu reaches China as death toll rises to eight
  By Jan McGirk in Bangkok
  28 January 2004

  Bird flu sweeping across Asia has reached China, authorities
  said yesterday, after dead ducks tested positive to the virus.
  A second boy died in Thailand yesterday, pushing the official
  number of human fatalities from bird flu in Vietnam and
  Thailand to eight.

  Five other suspicious deaths may be linked to avian influenza,
  but the test results in Bangkok are incomplete. Officials were
  due to gather in Bangkok today for an emergency health summit.

  -----------------------------------------------

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