What Is Severe Acute Respiratory Syndrome (SARS)?
Severe acute respiratory syndrome (SARS) has been a life-threatening viral respiratory illness caused by a coronavirus known as SARS-associated coronavirus (SARS-CoV) but usually shortened to SARS or SARS virus). SARS was associated with a flu-like syndrome, which progressed into pneumonia, respiratory failure, and sometimes death in some patients. The SARS virus is believed to have originated in the Guangdong Province in Southern China and had subsequently spread around the world in small outbreaks that have ceased since 2004. China and its surrounding countries have witnessed the greatest numbers of SARS-related cases and death.
The history of SARS is short. The SARS virus was first reported in 2002 in Asia and cases were reported until mid-year 2003. According to the World Health Organization (WHO), as of July 2003, a total of 8,437 people worldwide became ill with SARS and 813 died during the outbreak or epidemic. Illness was reported in more than 30 countries and on five continents. Only eight people in the United States acquired SARS infection, and all of these people had traveled outside of the U.S. No deaths due to SARS occurred in the U.S. The good news about SARS was that no outbreaks or epidemics have occurred since 2004.
Because of the rapid and unexpected spread of SARS, and because little is known about the virus, the U.S. Centers for Disease Control and Prevention (CDC) and the WHO have continued to closely monitor any outbreaks that result in a SARS-like illness. Guidelines and medical information about SARS can be found at the CDC and WHO web sites.
What Is the Cause of SARS?
The SARS virus spreads by close person-to-person contact. Transmission likely occurs by droplets produced when an infected person sneezes or coughs. Droplet spread can occur when airborne droplets, produced by a cough or sneeze, are deposited on the mucous membranes of the mouth, nose, or eyes of a person up to 3 feet away. The virus can also be spread when a person touches a surface contaminated with the droplets, as was found on many hospital surfaces, including elevator buttons. Oral-fecal transmission of SARS may also occur. Unprotected health-care workers were at significant risk of acquiring the infection during the outbreaks.
SARS virus replicates in both the lungs and gastrointestinal tract tissues. However, tissue samples show the most damage occus in the lung alveoli (air sacs) where lung function is compromised, producing a severe breathing disorder often termed acute respiratory distress syndrome (ARDS).
What Are SARS Risk Factors?
SARS risk factors include exposure to someone who's infected with the virus or to individuals traveling in an area where an outbreak of SARS is occurring. Other risk factors include male gender and individuals with other medical problems such as diabetes and chronic hepatitis B. Health-care workers who were exposed to SARS patients in the past outbreaks are also at increased risk of contracting the disease.
What Are the Signs and Symptoms of SARS?
Symptoms of SARS can be similar to those of other viral infections. The first symptoms begin two to seven days after exposure and include one or more of the following:
- Fever (temperature of more than 100.4 F)
- Fatigue (tiredness)
- Muscle aches and pain
- Malaise (a feeling of general discomfort)
- Decreased appetite
Respiratory symptoms develop three or more days after exposure. Respiratory symptoms include one of more of the following:
By day seven to 10 of the illness, almost all patients with laboratory evidence of SARS infection have pneumonia that could be detected in the lungs on X-ray films. Respiratory distress occurs in some patients. This symptom is a concern for the patient and the doctors because it suggests the disease is becoming more severe.
When Should Someone Seek Medical Care for Possible Exposure to SARS?
Acquiring SARS infection is usually associated with travel to a country where SARS has been reported or contact with an ill person who has just returned from that country. People who may be have been exposed to SARS or SARS-like outbreaks in the future should seek medical care immediately and are advised to call a doctor if a fever or respiratory symptoms develop and to tell health-care workers that possible exposure to SARS may have occurred.
What Specialists Treat SARS?
Primary-care physicians may treat the symptoms of mild SARS infections in some patients. Moderate to severe SARS-infected patients may require infectious-disease, critical-care, pulmonologists, and hospitalists as specialists to help care for these patients. In the U.S., CDC specialists should be informed immediately if an outbreak of SARS or SARS-like illness occurs.
What Tests Do Physicians Use to Diagnose SARS?
Initial tests for people thought to have SARS include the following:
- Chest X-ray films
- Pulse oximetry (a test in which a probe connected to a computer is placed on the finger or ear to measure oxygen saturation in the blood)
- Blood cultures
- Sputum (fluid from the respiratory tract) Gram stain and culture
- If SARS virus infection is suspected, the CDC should be notified; the CDC has specialized tests (RT-PCR and EIA) to identify the virus. These tests are not usually available to most laboratories although some state labs may have availability.
- Testing for viral agents such as influenza A, influenza B, bird flu, West Nile virus, anthrax, and respiratory syncytial virus (RSV) may be done to rule out these problems or infections that may be confused with SARS, especially if there is no initial suspicion that the problem is caused by SARS and if SARS testing is not readily available.
- Urinary antigen testing for Legionella and pneumococcal species (two causes of bacterial pneumonia)
Are There Home Remedies for SARS?
Follow the guidelines described in Prevention to limit the spread and transmission of SARS infection. Patients are usually treated in a hospital if they are diagnosed with SARS.
What Are SARS Treatments?
Currently, no specific treatment exists for SARS, although various treatments have been tried with unclear success. Specialists in infectious diseases and pulmonary care and others should be involved with the care of SARS patients. Medical treatments that have been tried include corticosteroids, antiviral agents, interferon, and various antibody preparations, nitric oxide, and a traditional Chinese medication termed glycyrrhizin (a compound found in licorice roots). Most of these treatments have not been studied enough to prove effectiveness. Most hospitalized patients require supportive care such as supplemental oxygen or mechanical ventilation.
People with confirmed or suspected SARS should be isolated and undergo aggressive treatment in a hospital. Mechanical ventilation (a device that assists in a person's breathing) and critical care may be necessary because of respiratory distress.
What Medications Treat SARS?
In some of the first cases of SARS, antibiotics were used with no success. Once it was determined that SARS was a virus, the antiviral drug ribavirin was used, sometimes in combination with corticosteroids. However, information is limited on whether or not these drugs will decrease the overall disease severity and death from SARS.
How Often Is Follow-up Needed After SARS Treatment?
SARS was (and possibly may be again in the future) a serious viral illness that requires prompt medical attention and hospitalization. Once the person is discharged from the hospital, follow-up care with a doctor should be scheduled.
How Can People Prevent SARS?
People in direct, close contact with someone who has had SARS were at greatest risk for infection. People with SARS or those at risk for SARS should follow the guidelines outlined below. The WHO and CDC have established guidelines to help in the prevention and spread of SARS.
- Limit time outside of the home. People with SARS should not go to work, school, child care facilities, or any public place until 10 days after their fever has ended and their respiratory symptoms are improving.
- Wash hands frequently with soap and hot water, use an alcohol-based hand rub, or both, especially after being in contact with bodily fluids such as respiratory fluids or urine.
- Wear disposable gloves when in contact with bodily fluids from a person with SARS. After use, throw the gloves away immediately and thoroughly wash the hands.
- Wear a surgical mask.
- Cover the nose and mouth with a tissue when sneezing or coughing.
- Do not share eating utensils, towels, or bedding. Thoroughly wash these items with soap and hot water after use by a person who is infected.
- Use a household disinfectant on any surface that may be contaminated, such as countertops or doorknobs. Wear disposable gloves while cleaning these surfaces.
- Follow these guidelines for at least 10 days after the symptoms have resolved.
What Is the Prognosis for SARS?
SARS can result in serious illness and medical complications that require hospitalization, intensive care treatment, and mechanical ventilation. The most recent numbers indicate that the death rate from SARS is higher than that of influenza or other common respiratory tract infections. Complications include altered lung function, polyneuropathy, and avascular necrosis.
The overall death (mortality) rate from SARS is about 10%. Age is a risk factor and plays a large role in the prognosis. Patients under 24 years of age have a mortality rate of about 1% while those over 65 years of age can have a 50% or higher mortality rate. Other risk factors include patients with chronic hepatitis B infection, hepatitis from any cause, diabetes, lymphopenia, leukocytosis, and high cytokine levels early (first week) in the SARS infection.