Severe acute respiratory syndrome (SARS) is a contagious illness caused by a coronavirus. It′s a disease that affects the lungs and airways, also called a respiratory illness. The coronavirus that causes SARS is called SARS-CoV-1. It first appeared in November 2002. Within a few months, the SARS-CoV-1 virus spread worldwide. It mainly passed from person to person.

A global effort from health experts quickly stopped the spread of the disease. No cases of SARS have been reported anywhere in the world since 2004.

SARS usually starts with flu-like symptoms, including:

• Fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.
• Chills.
• Muscle aches.
• Headache.
• Sometimes diarrhea.

After about a week, symptoms can include a dry cough and shortness of breath.

SARS is a serious illness that can lead to death. If you have any symptoms of a respiratory infection, call a member of your healthcare team right away. Also call your health professional if you have flu-like symptoms with a fever after you travel abroad.

SARS is caused by SARS-CoV-1, a strain of coronavirus. Coronaviruses are the family of viruses that also cause the common cold. A different strain of coronavirus, called SARS-CoV-2, causes COVID-19.

Coronaviruses can cause serious disease in animals. That's why scientists suspect that the SARS-CoV-1 virus might have started in animals and crossed to humans. It now seems likely that one or more animal viruses evolved into the new strain.

How the SARS virus spreads

Most viruses that cause respiratory illnesses, including SARS, spread when infected people cough, sneeze or talk. Tiny liquid particles from the nose or mouth enter the air. Healthy people nearby breathe in those particles. Most experts think the virus that causes SARS spreads mainly through close personal contact. For instance, a healthy person could get infected while taking care of someone who has SARS.

The virus also can spread on objects such as doorknobs, telephones and elevator buttons. Touching an object that has the virus on it and then rubbing the nose, eyes or mouth could cause an infection.

By and large, people at greatest risk of SARS are those who have had direct, close contact with someone who's infected. This includes healthcare workers and family members living with someone who has SARS.

Many people with SARS get pneumonia. And sometimes, a machine called a ventilator is needed to help with breathing. SARS is fatal in some cases, often because the body can't get enough oxygen or can't remove enough carbon dioxide. This condition is called respiratory failure. SARS also can lead to heart and liver failure.

The risk of getting very sick from SARS rises with age, especially in people older than 60. The risk also goes up if you have another long-term health condition, such as diabetes or chronic hepatitis B.

Researchers are working on various vaccines for SARS. But none has been tested in humans. If infections caused by the SARS virus happen again, follow some safety measures. The following tips are key if you care for someone who may have SARS:

• Wash your hands. Clean your hands often with soap and hot water. Or use an alcohol-based hand rub made with at least 60% alcohol.
• Wear disposable gloves. Put them on if you might have contact with an infected person's body fluids or feces. Throw the gloves away right after you use them. Then wash your hands well.
• Wear a surgical mask. Use it to cover your mouth and nose when you're in the same room as a person with SARS. Or you could wear a device called an N95 respirator. It also can help block the spread of the SARS virus. Wearing eyeglasses may offer some protection too.
• Wash personal items. Use soap and hot water to wash the utensils, towels, bedding and clothing of someone with SARS.
• Disinfect surfaces. Use a household disinfectant. Clean any surfaces that may have been in contact with sweat, saliva, mucus, vomit, stool or urine. Wear disposable gloves while you clean. Throw the gloves away when you're done. Then wash your hands.

Follow these steps for at least 10 days after the person's fever has gone away and any breathing symptoms have gotten better. The Centers for Disease Control and Prevention recommends that an infected person stay home from work or school during this time. Call your healthcare team right away if a fever or other symptoms start within 10 days of close contact with someone who has SARS.

When SARS first appeared, no specific tests checked for it. Now various tests can help detect the virus. These include tests of the blood, stool, nose and throat. But no known spread of the virus that causes SARS has happened anywhere in the world since 2004.

Scientists haven′t yet found an effective treatment for SARS. And antiviral medicines that clear up infections caused by viruses haven′t shown much benefit. Antibiotic medicines only work against bacteria, not viruses.

Hospital care for SARS involves easing symptoms while the SARS virus runs its course. Care might include receiving fluids through a vein and extra oxygen if needed.