Clinical features, pathogenesis and immunobiology of severe acute respiratory syndrome.

PURPOSE OF REVIEW: Severe acute respiratory syndrome coronavirus is a novel virus responsible for the major pandemic in 2003, and it re-emerged in China in late 2003 and 2004 following resumption of wild animal trading activities. Over the past few years, research work has looked into factors that may lead to super-spreading events, clinical/laboratory parameters that may differentiate severe acute respiratory syndrome from other causes of community-acquired pneumonia, the origin of severe acute respiratory syndrome, reservoir host distribution and transmission routes. A better understanding of these issues may help prevent and control future outbreaks of severe acute respiratory syndrome.

RECENT FINDINGS: Bats are natural reservoirs of severe acute respiratory syndrome like coronaviruses. The human and civet isolates of severe acute respiratory syndrome coronavirus nestle phylogenetically within the spectrum of severe acute respiratory syndrome like coronaviruses. Severe acute respiratory syndrome has the potential of being converted from droplet to airborne transmission. When evaluating epidemiologically high-risk patients with community-acquired pneumonia and no immediate alternative diagnosis, a low absolute neutrophil count on presentation, along with poor responses after 72 h of antibiotic treatment, may raise the index of suspicion for severe acute respiratory syndrome.

SUMMARY: The presence of severe acute respiratory syndrome like coronaviruses in horseshoe bats raises the possible role of bats in previous and potentially future severe acute respiratory syndrome outbreaks in human. Healthcare workers should take adequate respiratory protection in addition to strict contact and droplet precautions when managing patients with severe acute respiratory syndrome.