WHO, CDC Revise SARS Case Definition
Coronavirus Testing Now Included in SARS Diagnosis
May 1, 2003 -- As the number of SARS cases continues to climb in China, health officials from the World Health Organization (WHO) and the CDC have revised the case definition of SARS (severe acute respiratory syndrome) to include a diagnostic test to detect the virus -- and antibodies to the virus -- believed to cause the disease.
Worldwide, 5,865 probable SARS cases have now been reported to the WHO, including 391 deaths -- an increase of 202 cases and 19 deaths from yesterday. China continues to harbor more SARS cases than the rest of the world combined. Chinese officials today reported 187 new SARS cases and 11 deaths, and more than half of those new SARS cases were in the capital, Beijing.
Health officials say the future of SARS now largely depends on whether the disease can be controlled in China over the next few months. The WHO says hospitals in China's poorer provinces may not be able to handle the continued spread of SARS and may require support.
By adding laboratory evidence of the SARS-related coronavirus to the SARS case definition, health officials hope more effectively to dismiss patients with illnesses caused by conditions other than SARS and develop better treatments.
According to the new case definition, a probable case of SARS is considered someone who meets all of the following diagnostic criteria:
High fever (over 100.4 degrees Fahrenheit);
- Respiratory symptoms, such as cough, difficulty breathing;
- X-ray evidence that suggests pneumonia or respiratory distress syndrome;
- A travel history within 10 days of the start of symptoms to an area where SARS is present or close personal contact with a known SARS patient; AND
- Laboratory evidence that shows the presence of the SARS virus or antibodies to it.
But officials admit that currently available testing methods for the SARS coronavirus are not foolproof. Each of the tests has certain strengths and weaknesses.
For example, PCR tests that scan for a small portion of the virus' genetic makeup are faster than viral culture or antibody tests, but they are less precise than the more traditional and time-consuming methods and, therefore, may produce a false positive or negative result.