Newly emerged respiratory infections – SARS and H5N1

Abstract

Two newly emerged respiratory viruses, SARS-CoV and the highly pathogenic avian influenza A H5N1 virus, have arisen in Asia at the turn of the millennium. They both have the potential to cause global pandemics, facilitated by modern high-speed international transportation. Molecular studies suggest that SARS-CoV could be transmitted to humans from civet cats and other game animals consumed as a culinary delicacy. The H5N1 virus appears to be endemic in bird and poultry populations in Asia, with sporadic transmission to humans. Both SARS-CoV and H5N1 begin with a non-specific influenza-like illness, progressing rapidly to severe pneumonia and ARDS. Although various antiviral and immunomodulatory agents have been tried, or postulated to be useful, none has been proven effective by RCTs. Treatment remains supportive and the mortalities are high for both conditions. No vaccine has yet been approved for either infection, although infection control measures have been found to be effective in hospital settings. While all known chains of person-to-person transmission of SARS were broken in July 2003, a few small pockets of outbreak have occurred since, related to laboratory accidents and contact with game animals. The World Health Organisation has consistently warned of a H5N1 pandemic, and the medical community needs to stay vigilant. Minimising human contact with potentially infected animals, sound infection control measures in hospitals, farms, and markets, and prompt isolation of suspected cases are the mainstays in preventing large-scale outbreaks for SARS and H5N1.