China has announced four confirmed or suspected SARS cases, one of whom has died.
Health officials stepped up their alert level as the health ministry rushed to identify the source of the unexpected re-emergence of Severe Acute Respiratory Syndrome (SARS).
Experts think this outbreak can be traced back to infection by laboratory workers. A laboratory inside the Center for Disease Control in Beijing may have played a key part.
One of the confirmed cases, a 26-year-old medical student
identified by her surname Song, conducted research at the laboratory for two weeks last month.
She later returned to her home province, Anhui in eastern China,
where she was hospitalised with fever and tended to by her mother. The mother died early this week but post-mortems have not yet definitively established her as a SARS case.
Another confirmed case, 20-year-old Beijing nurse Li Na, worked in the respiratory department of Jiangong hospital, where Song had been briefly hospitalised before going home to Anhui.
The second suspected SARS case also had ties to the Beijing
Center for Disease Control. The patient, a 31-year-old researcher surnamed Yang, had worked at the centre's laboratory.
Authorities put 117 people who had been in contact with the Anhui cases under observation. In Beijing, 188 people were deemed to have been in close contact with the 20-year-old nurse and five of them had developed fever.
The five, who included three relatives, also displayed SARS
symptoms, unlike people who had come into contact with four
confirmed SARS cases in southern China in the winter.
