SARS (Severe Acute Respiratory Syndrome)
SARS (Severe Acute Respiratory Syndrome) is a recently identified infectious disease caused by a coronavirus. Coronaviruses, so named for the crown or halo surrounding them, usually cause mild illnesses such as the common cold. The coronavirus that causes SARS is more virulent, and was unknown until a worldwide outbreak of the disease in 2002-03.
The SARS virus spreads in respiratory droplets from sneezes and coughs to people in close contact with an infected person. Close contact includes living with, looking after, or being in physical contact with an infected person. The virus may also spread in other ways that are not yet known. The incubation period, or length of time between exposure to the virus and signs of the first symptoms, is usually 2 to 7 days, but up to 14 days in some cases. SARS is thought to be contagious only once symptoms have begun.
The initial symptom of SARS is a high fever (>38ºC). Infected people may also experience a headache, muscular aches, shortness of breath, a dry cough, and diarrhea. Because the symptoms of SARS are common to other respiratory infections such as influenza, diagnosing SARS is difficult. A rapid diagnostic test is not available, so doctors assess possible cases for a combination of high fever, other symptoms, and chest X-rays showing respiratory distress that is consistent with SARS infection. There is no treatment specific for the SARS virus, but infected people are treated in the same way as patients with viral pneumonia. In some cases, SARS is fatal. Currently there is no cure or vaccine for SARS, but scientists around the world, including in Canada, are testing antiviral drugs as possible treatments and are working on developing a vaccine.
The first case of SARS was reported in China in November 2002. The virus then spread to over 20 countries, including Canada. The ease of global travel aided the rapid spread of this new infectious disease. Human-to-human spread of SARS was declared to have stopped in July 2003. During the outbreak period, from 1 November 2002 to 31 July 2003, 8096 people were infected, 774 of whom died, according to the World Health Organization. In Canada, the outbreak began in March 2003 among people who had travelled to Hong Kong. During the outbreak, thousands of Canadians were quarantined and the World Health Organization issued a travel advisory for Toronto. In total, 251 Canadians were infected with SARS and 43 died. In early 2004, China reported another SARS outbreak; it was contained without spreading outside the country.
The origin of the SARS virus is unclear. Scientists with the World Health Organization, however, have linked SARS with civet cats, members of the mongoose family that are a delicacy in parts of China and may be carriers of the SARS virus.