What is SARS?
Severe Acute Respiratory Syndrome (SARS) is a respiratory disease found in humans caused by the SARS coronavirus (SARS-CoV). Between November 2002 and July 2003 there were 8096 infected cases but it has since been contained although not eradicated.
Causes of SARS
Coronavirus has been confirmed as the disease causing virus by laboratories around the world after the SARS outbreak in 2002.It is a positive strand, enveloped in RNA virus that is found in animals causing enteric or respiratory infections in them. It was later found that palm civets sold as food in the local market in Guangdong, China had SARS coronavirus in them although there were no external manifestations of the same. This is believed to be the origin of the outbreak. Other animals such as raccoon dogs, ferret badgers and Chinese bats were later found to contain the deadly Severe Acute Respiratory Syndrome virus.
Diagnosis of SARS
SARS can be suspected in anybody with a body temperature above 100.4 F, travelled to any area that has seen a recent outbreak of the disease or has had casual or sexual contact with a person diagnosed of SARS in the last ten days. Chest X rays of an infected person will be similar to that of a person suffering from pneumonia or respiratory distress syndrome. Blood tests usually show that counts of platelets and white blood cells are high.
After the RNA (Ribonucleic acid) of the virus responsible for the SARS outbreak in 2003 was identified and sequenced, multiple kits for the diagnosis of SARS have been developed. They are being tested to determine whether they are suitable enough to be used. It is also to be noted that each one has its drawbacks. There are three possible tests to detect Severe Acute Respiratory Syndrome and they are ELISA (twenty days after the symptoms appear), immunofluorescence assay test (ten days after onset) and the polymerase chain reaction test.
Prevention of SARS
Avoiding contact with people suspected of having SARS infection and travelling to places that have reported positive cases in the recent past are the best methods of prevention. Quarantining persons suspected of infection is helpful in containing the disease. The screening of passengers by airport authorities during the 2003 SARS breakout also helped to prevent the spread of the disease to other places.
Prognosis of SARS
In the outbreak of 2002-2003, there were 8096 known cases of infection and 744 confirmed cases of human death according to the WHO records. Mortality rate was found to be 1% for people aged 24 or less, 6% for those between 25 -44 years, 15% in the 45-60 age group and 50% for those above 60 years. Some people who survived the Severe Acute Respiratory Syndrome virus have later suffered from pulmonary fibrosis, osteoporosis, and femoral necrosis due to which depressive disorders are also common amongst them.
Antiviral drugs against coronaviruses were not a priority before the SARS-CoV was discovered. The rapid global outbreak of the virus has propelled serious research into understanding and finding a cure against it. Clear understandings of the pathogenesis and genome structure of the SARS virus have revealed possibilities for therapeutic intervention. Development of drugs that are effective against SARS-CoV can lead to better prevention and treatment of added viral infections in humans and animals.
Possible vaccines that can protect against the Severe Acute Respiratory Syndrome virus as well as other variants of the virus are being developed. Passive immunization was found to be successful in containing SARS- CoV.
Symptoms of SARS
- Fever(above 38 C or 100.4 F)-only symptom found consistently among all patients
- Muscle pain
- Gastrointestinal symptoms
- Sore throat
- Shortness of breath(may occur at a later stage)
- Other non-specific symptoms
Treatment and Medication for SARS
As of now treatment has mostly been supportive with the use of antipyretics, supplemental oxygen and ventilator support. Antibiotics are ineffective as it is a viral infection. Infected persons are isolated in negative pressure rooms and all direct contact is avoided. All known antiviral treatments are being tested on the SARS-CoV. It has been found that more damage is done by the body’s own immune system when it overreacts to the virus. Corticosteroids (marketed as Prednisone) and Ribavirin are the most commonly used drugs against SARS. A combination of Kaletra, Ribavirin and corticosteroids have proven more effective than when the drugs are used separately. Use of human interferon and Glycyrrhizin have also yielded positive results. Iminocyclitol 7 has had partial success against the SARS-CoV.