What is SARS?
Severe acute respiratory syndrome (SARS) is a viral infection that causes a contagious respiratory illness which can lead to death. It should not be confused with the bird flu or swine flu which are also viral infections but caused by different strains of the influenza virus which are related to the seasonal flu. The SARS virus is related to the common cold virus but is much more severe and deadly. All of these viruses cause respiratory tract infections but in severe cases where complications arise other organs and systems may also be affected.
SARS first emerged in late 2002 in China but spread worldwide. By 2003 it had infected around 8,000 people and killed 774 people. However, these are the numbers of known infections and deaths from SARS and it is possible that many more people were infected and died from SARS during the 2002-2003 outbreak. Another serious viral infection has emerged in 2013 known as Middle East respiratory syndrome (MERS) which has many similarities with SARS.
Causes of Severe Acute Respiratory Syndrome
SARS is a viral infection meaning is caused by a virus. The specific type of virus responsible for SARS is known as a coronavirus (SARS-CoV). It is the same family of virus as the common cold and MERS. The SARS virus is not new and has existed in animals such as bats, pets and livestock. However, until 2002 it was not known to infect humans. It is believed that humans living in close proximity with livestock in parts of China may have been the way the virus ‘jumped’ from animals to humans.
How SARS is spread?
Although the virus may have initially been transmitted from animals to humans, the virus was eventually able to spread from human to human. The virus is spread by droplets released from an infected person during coughing or sneezing. These droplets travel through the air and the virus can then infect another person when it enters their nose or mouth or settles on the outer surface of the eye. However, it does not have to be spread with close contact since the virus can exist in even dried droplets for hours after being expelled from an infected person.
How does SARS cause disease?
Once the virus enters the body it multiplies rapidly. In order to do this the virus needs to enter the human host cell and replicate. It is now known that the cells of the respiratory tract and gastrointestinal tract are specific for supporting the SARS-CoV replication. For this reason it is results in conditions like pneumonia and there may be symptoms like diarrhea. However, SARS is not limited to the respiratory and gastrointestinal systems and can lead to complications like heart and liver failure.
Who is at risk of SARS?
Any person who comes in close contact with an infected person is at risk. Family members of an infected person and health care workers are usually at a much higher risk due to prolonged periods of close contact. Older people and those with underlying diseases especially where the immune system is weakened are also at risk but only if they come in contact with a person with SARS. Since the virus can remain in droplets for up to 3 hours after it dries, making contact with inanimate objects that are contaminated can still transmit the virus.
Signs and Symptoms
SARS does not present with unique signs and symptoms. In fact it is often mistaken for the common cold or flu at the outset. The more common symptoms include:
- Fever (100.5F / 38C or higher)
- Persistent cough
- Difficulty breathing (dyspnea)
- Muscle pains (myalgia)
Less common symptoms of SARS includes:
- Runny nose
- Sore throat
- Nausea and vomiting
Symptoms do not appear immediately after infection. It can take 2 to 3 days before symptoms arise.
Diagnosis of SARS
Since the signs and symptoms of SARS are not specific for this viral illness, laboratory tests may be necessary to confirm a diagnosis of SARS. It requires a sputum or blood sample. These tests aim to detect the presence of antibodies against the SARS virus. However, these tests were not available during the 2002-2003 SARS outbreak. Airport scanners may be used to detect whether a traveler has a fever but this is not conclusive for SARS since many infectious and even some non-infectious diseases can cause a rise in body temperature.
Treatment of SARS
There is still no cure for SARS. It is a viral infection and cannot be treated with antibiotics that are effective against bacteria. Although antiviral drugs have been useful in treating certain viral infections, it is of limited value against the SARS virus. Combinations of corticosteroids and certain antiviral drugs has been used to treat SARS but the effectiveness is largely based on anecdotal evidence. Antibodies may also offer some hope but it appears to only be effective as an early preventative measure against SARS rather than a treatment for a full blown infection. Currently treatment depends on supportive measures until the body can overcome the virus itself if possible.
Prevention of SARS Infection
As yet there is no conclusive scientific evidence that the SARS vaccine developed in 200. The disappearance of the virus in humans means that the vaccine has not been thoroughly tested in human clinical trials. However, there are a host of preventative measures that people can take to limit the chances of developing SARS. These measures are similar to preventative strategies for most other viruses transmitted by droplet spread.
- Avoid making close and repeated contact with person who is known the be infected with SARS.
- Wash the hands thoroughly with an antiseptic soap or hand wash several times in a day.
- Do not place the hands near the mouth, nose or eyes unnecessarily. If these areas have to be touched then the hands should be thoroughly washed.
- Disinfect surfaces on a regular basis with an appropriate disinfectant and wash all personal items which may have come in contact with droplets from a person infected with SARS.
- Wear gloves and a surgical mask where necessary, especially among health workers. Even touching the stool or feces of a person with SARS can be a means of transmitting the virus.