Disease

SARS

Overview / History

The beginning: a new disease
In late November 2002, the first cases of what would become known as Severe Acute Respiratory Syndrome (SARS) were reported as an outbreak of atypical pneumonia in China's Guandong province. Between November 16, 2002 and February 7, 2003, Chinese authorities reported 305 cases, including five deaths. They announced that they had found the cause of the disease and said the outbreak was under control.

But the outbreak had already spread beyond Guandong province. Later in February 2003, a 33-year-old man who had visited the Fujian province of China died of pneumonia in Hong Kong. Several other members of his family also developed symptoms of pneumonia. Towards the end of February, a doctor who had been infected in southern China spent just one night in a hotel in Hong Kong. This single event allowed SARS to spread internationally - before the doctor left the hotel, at least 16 hotel visitors or guests had been infected.

The disease was first identified in Vietnam on February 28, 2003. On March 12, the first public warning was issued by WHO. A global alert was released concerning cases of atypical pneumonia in Vietnam, Hong Kong and Guangdong province, China. Some patients were recovering, but others remained critically ill.

Global situation: 2003 outbreak
The March 12 global alert did not stop SARS from spreading. The disease continued to infected people both near the original outbreak sites and internationally. Hong Kong, Hanoi, Singapore, Toronto and China all reported cases before the March 12 alert, and these areas experienced the most devastating outbreaks. Taiwan had a high level of awareness and preparedness, but was unable to prevent imported cases from causing a major SARS outbreak. The outbreak peaked in May 2003. More than 200 new cases were reported daily.

By the time the outbreak was contained in July 2003, cases had been reported in 33 countries. (In most countries, cases were imported. The only areas that experienced local transmission of SARS were mainland China; Beijing; Hong Kong; Taiwan; Hanoi, Vietnam; Toronto, Canada; and Singapore.) In all, more than 8,000 people were infected. Of them, nearly 800 died.

After the 2003 outbreak
SARS has reappeared in isolated incidents related to laboratory accidents. The first occurred in Singapore in September 2003, when a researcher contracted SARS from his laboratory. The second case was reported in Taiwan in December 2003. Again, a research worker who was handling the SARS virus became infected.

Between December 2003 and January 2004, the disease surfaced in seemingly isolated spontaneous infections. Four cases of SARS occurred in the Guangdong province of China, the area considered the origin of the 2003 outbreak. All four patients recovered and did not appear to spread the disease to others. The source of their infections was not confirmed, though in one case civet cats were suspected.

The last outbreak of SARS occurred in China in April 2004 and was contained by May that year. Two researchers who worked in a lab where live SARS virus was kept contracted the disease, although they did not work directly with the virus. One of the workers spread the disease to two others, who in turn passed the infection on to another five people. Of the nine cases, one person died.

Studies have shown that SARS probably moved from animals to humans in at least two different outbreaks in 2003 and 2004. The exact path of infection is not known. It appears that at least a few people contracted the disease from an infected civet. Whether the civet is a natural host, or was infected by contact with another animal (such as a bat), is unclear. It is possible the disease may infect humans again in the future.

Mode of spread

Airborne (e.g. pollution)
Coughing / Sneezing

Transmission

SARS is mainly spread through droplets coughed or sneezed into the air by an infected person. Droplets are large infected particles that can only travel about 3 feet. Therefore, a person must be quite close to a SARS patient to become infected. Risk of infection is highest for people who come into close contact with SARS patients, like family members or medical professionals.

It is also possible for infected particles to settle on objects in the environment. The SARS virus may be able to stay active outside the body for several days. A healthy person can become infected if they touch a contaminated object, and then touch their mouth, eyes, or nose.

Symptoms

SARS symptoms are similar to those of pneumonia and influenza. They include:

A fever of at least 100.4 degrees Fahrenheit/38 degrees Celsius, possibly accompanied by chills
Headache
General discomfort
Body aches
Runny nose and sneezing are not typically associated with a SARS infection.

Fever is typically the first sign of infection. It usually appears two to seven days after a patient has contracted the disease, though the incubation period can last up to 10 days. Some patients, about 10 to 20 percent, also have diarrhea. Within two to seven days, a dry cough sometimes appears. Some SARS patients develop pneumonia. That can lead to an insufficient amount of oxygen in the blood (hypoxemia) and other complications.

Treatment

SARS, like influenza, is a viral illness. Antibiotic medicines have no effect on viral illnesses. Fortunately, most patients begin to improve on their own within a week of developing symptoms.

In more serious cases, patients have been treated with a variety of antiviral drugs. These were sometimes given in conjunction with steroids. These treatments remain somewhat controversial. After the 2003 outbreak, the World Health Organization (WHO) commissioned a study to review the various treatments used. It concluded that it was impossible to tell if any treatment worked against the disease. Most data available showed inconclusive results, and a few even showed that the treatments were harmful to the patients.

Severe SARS cases may be treated with intensive care support, such as IV fluids and mechanical respiratory assistance. People infected with SARS may develop secondary bacterial infections, such as pneumonia. Bacterial illnesses can be treated with antibiotics.

Prevention

Risk to travellers

Few cases of SARS occurred among travelers, since close contact with a SARS patient is usually required in order to become infected. All SARS-related travel advisories have been lifted. It is safe to travel to areas where SARS occurred during the 2003 outbreak.

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