Chinese health authorities have announced that an additional case of SARS is under investigation. This brings the total number of cases in China, reported since 22 April, to nine. Of these, one has died.
The new case, in Beijing, is a 49-year-old female retired doctor. On 12 April, she was admitted to the same hospital ward where a 20-year-old nurse was being treated for pneumonia. The former doctor began developing SARS-like symptoms on 19 April and on 22 April was transferred to Ditan Hospital and placed in isolation. Her condition is listed as critical.
The 20-year-old nurse, previously reported to WHO as a confirmed case, has been linked to an additional five cases. These include the one reported today and four reported on Sunday. To date, all cases have been linked to chains of transmission involving close contact with an identified case. The second confirmed case, who remains hospitalized in Anhui Province, is a 26-year-old postgraduate student who had been conducting research at Beijing’s Institute of Virology. She is thought to be the index case in the present outbreak.
During the 2003 outbreak, the transmission of SARS was greatly amplified in hospital settings. As a risk reduction strategy in Beijing, all seven SARS cases are now being treated in Ditan Hospital.
However, patients were treated or assessed in open wards at seven hospitals (five in Beijing and 2 in Anhui) before suspicions of SARS were raised and procedures of isolation and infection control were introduced. In addition, the two patients in Anhui travelled long distances within China by train.
As these events created opportunities for multiple exposures, Chinese authorities have undertaken extensive tracing and follow-up of contacts. In Beijing, nearly 700 persons have been isolated or placed in quarantine.
SARS has a relatively long incubation period, generally accepted to be 10 days. Based on present knowledge about the disease, persons exposed to the virus are not infectious prior to the onset of symptoms. For these reasons, rapid detection and isolation of cases, and rapid tracing and follow-up of contacts have been successfully used to bring a SARS outbreak under control.