Severe acute respiratory syndrome, commonly referred to as SARS, is a respiratory illness that is both contagious and sometimes fatal. SARS was first identified in China in November 2002 and within only a few months, the disease spread across the world.1
According to the World Health Organization (WHO), by July 2003 a total of 8,437 people worldwide had become ill with SARS, leading to 813 deaths. Cases were reported in over 30 countries across five different continents.
The US was not particularly affected; only 27 probable cases have been recorded, with no fatalities related to SARS.11 Eight of these cases had serologic evidence to support a diagnosis of SARS, while other cases remain under investigation.12
Strong levels of global cooperation ensured that the threat of SARS was dealt with swiftly, and the spread of the disease was effectively contained.
Since 2004, there have been no new SARS outbreaks anywhere in the world. Organizations such as the Centers for Disease Control and Prevention (CDC) are preparing and planning in case the threat of SARS re-emerges.
Contents of this article:
You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Fast facts on SARS
Here are some key points about SARS. More detail and supporting information is in the main article.
- The coronavirus that causes SARS belongs to the same family of viruses as the common cold.
- It is believed that SARS is spread through droplets in the air and close person-to-person contact.
- Normally, the symptoms of SARS develop within 2-7 days.
- Most patients that have SARS go on to develop pneumonia.
- Serious complications arising from SARS are most likely to affect people aged over 60 and people with other chronic illnesses such as diabetes or hepatitis.
- SARS is so rare that its diagnosis mainly depends on whether a person has an obvious history of exposure to the virus or not.
- The CDC recommends that people with SARS receive the same treatment as people with community acquired atypical pneumonia.
- To stop the spread of infection it is vital that anyone with SARS limits interaction with other people.
- Personal hygiene measures such as hand washing help to reduce the risk of spreading the disease.
- There have been no recorded cases of SARS anywhere in the world since 2004.
What is SARS?
SARS is a disease caused by the SARS coronavirus (SARS-CoV). Coronaviruses are a common form of virus that typically cause upper-respiratory tract illnesses in the majority of cases.3 Coronaviruses are the family of viruses that are responsible for the common cold.4
SARS was first discovered in China in November 2002.
There are currently six different kinds of coronavirus known to infect humans. Four of these are particularly common, and most people will be infected by at least one of these at some time in their life. The other two cause SARS and Middle East Respiratory Syndrome (MERS), which are far less common but far more deadly.
Before the emergence of SARS, coronaviruses had not been particularly dangerous to humans, although they had been known to cause severe diseases in animals. As a result, SARS-CoV was initially thought to have been transmitted from animals to humans; scientists now believe that an animal virus mutated into a new, more deadly strain.
What causes SARS?2,3,4
The SARS virus is thought to be spread through the air, via coughing and sneezing, or through close person-to-person contact. SARS-CoV is likely to be transmitted in respiratory droplets and be absorbed into the body through the mucous membranes of the mouth, nose and eyes.
Examples of person-to-person contact includes the following:
- Hugging and kissing someone
- Sharing utensils for eating and drinking
- Speaking to someone within 3 feet of them
- Touching someone directly.
A person with the virus can spread the infection by leaving respiratory droplets on objects, such as door handles, doorbells and telephones, which are then picked up by someone else.
Recent developments on SARS causes from MNT news
Scientists have discovered that two new coronaviruses found in Chinese horseshoe bats are a close relative of the SARS-coronavirus. This is according to a new study published in the journal Nature.
Scientists say there are approximately 320,000 viruses present in mammals that are yet to be discovered, according to a study published in the journal mBio.
Signs and symptoms of SARS2,5,6
Following exposure to the virus, the symptoms of SARS tend to develop within 2-7 days. During the incubation period before SARS manifests itself, the disease is not contagious.
SARS typically begins with the onset of high fever.
Most cases of SARS begin with a high fever, with a temperature exceeding 100.4 degrees F (38 degrees C). Other early symptoms include those common to flu, such as aches, chills, diarrhea, dry coughing and shortness of breath. These will develop over the course of a week.
Most patients go on to develop pneumonia, an infection of the lungs, which is the leading cause of death in children below the age of 5 worldwide.7
Serious complications such as respiratory failure, heart failure and liver failure are also a risk. These complications are more likely to affect people over 60 years of age, particular people with pre-existing co-morbidities such as diabetes or hepatitis.8
Tests and diagnosis of SARS9
At present, there is no specific test that can be used to diagnose SARS quickly enough to be able to inform the patient's treatment. As a result, diagnosis of SARS currently depends on the observance of a patient's clinical and epidemiological features.
The majority of patients who developed SARS in 2003-2004 had a clear history of exposure to people who had developed the disease or to places where transmission of the disease had been ongoing. SARS patients also normally develop pneumonia, so a combination of pneumonia and history of exposure to SARS is suggestive of the patient having developed SARS.
Guidelines recommend that patients should only be considered to have SARS if they require hospitalization for otherwise unexplained pneumonia and have a history of suspected exposure to the virus. This can include recent travel to an area previous affected by SARS or working in a laboratory that contains live SARS-CoV.
The WHO gives the following as the clinical case definition of SARS:
- A person with a history of fever (of at least 38°C) AND
- One or more symptoms of lower respiratory tract illness: cough, difficulty breathing, shortness of breath AND
- Radiographic evidence to suggest a diagnosis of pneumonia (or evidence on autopsy consistent with pneumonia) AND
- No alternative diagnosis to fully explain the illness.
Travelling to an area previously affected by SARS could increase the risk of developing the disease.
In the unlikely event of a health care provider needing to test for SARS, there are a number of laboratory tests available, including:
- Polymerase chain reaction (PCR) - can detect the genetic material of the virus in the patient's blood, stool or nasal secretions
- Serologic testing - can detect antibodies to the virus in the patient's blood using ELISA or IFA
- Viral culture and isolation - where a small sample of tissue or fluid is taken from a patient and then container with cells in to see if the virus grows.
Treatment and prevention of SARS6
The CDC recommends that people with SARS should have the same treatment as people that have developed community-acquired atypical pneumonia. Such treatment includes the use of medications to reduce fever, as well as cough medicine to alleviate the symptoms.10
Washing hands is a key way of reducing the chances of passing on SARS.
As with other infectious diseases, there are some simple steps that can be taken to help prevent the SARS virus from spreading. For example, good personal hygiene practices can help restrict the spread of the virus and involves:
- Frequent handwashing
- Avoiding touching the eyes, mouth or nose with unclean hands
- Covering the mouth and nose with a tissue when coughing or sneezing
- Encouraging others to do the same.
Because SARS is contagious once its symptoms have developed, it is important that people with the disease limit their interactions with other people until 10 days after their symptoms have improved. SARS is at its most contagious during the second week of illness.
Recent developments on SARS treatment from MNT news
A new study led by researchers from Purdue University in West Lafayette, IN, details a way of disabling a part of the virus involved in severe acute respiratory syndrome that allows it to hide from the immune system - a finding that may lead to the development of a vaccine against the disease.
No specific drugs exist to work against coronaviruses - the pathogens behind severe acute respiratory syndrome and Middle East respiratory syndrome - but research published in the journal PLOS Pathogens unveils a new coronavirus inhibitor.
As stated previously, there haven't been any recorded cases of SARS anywhere in the world since 2004. Since this time, the CDC have been working with various organizations - federal, state and local - to plan and prepare a response should SARS reappear at any point in the future.