New Respiratory Viral Infections

1 Severe acute respiratory syndrome(SARS)is caused by a previously unrecognized coronavirus (CoV)which jumped species and became adapted to be transmissible between humans in2002 . Enormous scientific knowledge about this SARS-CoV has been accumulated and aspects of its pathogenesis defined .However it is still unclear why some members of the same family or housing estate with SARS outbreak were more susceptible to SARS than others.Similarly,why children have a lower incidence of SARS with milder clinical course as compared to adults remains unknown.