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Studies, views and experiences about the virus

	Stability of SARS virus - May 4, 2003
	The Hong Kong Experience By Gunnar J. Kuepper - April 2
	Articles by WHO in English and French: -Measures for persons untertaking international travel from areas affected by  SARS -Mesures recommandees par L'OMS a l'intention des voyageurs provenant  de zones touchees par le syndrome respiratoire aigu severe (SRAS) -Global Surveillance for SARS -Surveillance mondiale du SRAS -SARS Case reporting form -Fiche de declaration des cas SARS

April 7: Status of diagnostic tests

The development of a diagnostic test, which is being pursued around the clock by the WHO collaborating network of 11 laboratories, has proved more problematic than hoped. Three diagnostic tests are now available and all have limitations as tools for bringing the SARS outbreak quickly under control.

The ELISA detects antibodies reliably but only from about day 20 after the onset of clinical symptoms. It therefore cannot be used to detect cases at an early stage before they have a chance to spread the infection to others.

The second test, an immunofluorescence assay (IFA), detects antibodies reliably as of day 10 of infection, but is a demanding and comparatively slow test that requires the growth of virus in cell culture.

The presently available PCR molecular test for detection of SARS virus genetic material is useful in the early stages of infection but produces many false-negatives, meaning that many persons who actually carry the virus may not be detected - creating a dangerous sense of false security for a virus that is known to spread easily in close person-to-person contact.

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