MAIN SYMPTOMS:
* High fever (>38° Celsius);
* Dry cough;
* Shortness of breath or breathing difficulties; Changes in chest X-rays indicative of pneumonia also occur;
* SARS may be associated with other symptoms, including headache, muscular stiffness, loss of appetite, malaise, confusion, rash and diarrhea.How contagious is SARS?

Based on currently available evidence, close contact with an infected person is needed for the infective agent to spread from one person to another. Contact with aerosolized (exhaled) droplets and bodily secretions from an infected person appears to be important… the amount of the infective agent needed to cause an infection has not yet been determined. Source: The World Health Organization

CLINICAL FEATURES
SARS was first recognised at the end of February in Hanoi, Vietnam. The agent is highly infectious, with attack rates of >50% among healthcare workers caring for patients with the syndrome. Preliminary data from the first cluster of about 60 probable cases in Hanoi indicate an incubation period of 5-9 days. The most common early systemic symptoms in Hong Kong and Hanoi include fever, malaise, myalgia, headache, and dizziness. Sore throat and rhinorrhoea occur early in fewer than 25% of cases, and cough occurred early in only 39% of cases. Because of its non-specific early manifestation, sudden acute respiratory syndrome will be overlooked unless clinicians have a high index of suspicion and seek a history of travel or contact with the syndrome.

After 3-7 days of fever the lower respiratory phase begins, with a non-productive cough, which may be accompanied by dyspnoea and chest pain. Breathlessness requiring oxygen occurred in many cases after about five days and progressed to hypoxaemia requiring ventilatory support in around 15%, a rate similar to the 10-20% observed elsewhere. Early chest x ray findings typically show small focal unilateral diffuse interstitial infiltrates, which may be overlooked initially. The appearance evolves rapidly, often becoming more generalised and affecting both lung fields. Chest radiographs may, however, be normal during the febrile prodrome and throughout the illness. Lymphocytopenia is common and occasionally liver function values are raised.

Clinical presentation suggests an illness of variable severity ranging from mild illness to death. The speculation is that the most severe illnesses occur among first level contacts of an index case. If real, this may reflect either repeated high dose exposure of the unsuspecting healthcare workers to the index case or attenuation of the pathogen during subsequent waves of infection. Source: British Medical Journal 2003;326:669-670 ( 29 March ) Editorial "Sudden acute respiratory syndrome"

SARS: Questions and answers
adapted from CBC News Online | Updated March 26, 2003
* What are the symptoms?
* What causes SARS?
* What are the risks?
* Where did SARS originate?
* What does the Toronto quarantine mean?
* What are governments doing?
* What about travel?
* How are patients being treated?

The World Health Organization calls Severe Acute Respiratory Syndrome, or SARS, a new communicable disease that is a global health threat. More than 480 people have recently fallen ill from the potentially fatal disease, which has spread around the globe by air travel.

What are the symptoms?
The disease spreads from person to person. It often begins with a high fever, headache and sore throat. Other possible symptoms include loss of appetite, confusion, rash and diarrhea. Not everyone has reacted the same way.

The World Health Organization said doctors are on the lookout for those symptoms with:
* a fever over 38 C AND
* cough, shortness of breath, difficulty breathing AND
* close contact with someone diagnosed with SARS or a history of travel to affected areas, including Toronto, Vancouver, Guangdong province in China, Hong Kong, Singapore and Hanoi, Vietnam.

The respiratory symptoms appear two to seven days after exposure. The disease has been compared to influenza and pneumonia, but for lack of a better description, WHO has called the disease SARS.

What causes SARS?
Researchers don't know whether bacteria or a virus causes SARS, and it may take several weeks to find out. "It is most likely to be viral, but that is not a certain thing at this point," said Dr. Andrew Simor, head of microbiology and a specialist in infectious diseases at Toronto's Sunnybrook and Women's College Health Sciences Centre.
Tests have failed to show it is influenza. The leading candidate has been human metapneumovirus, a family of microbes that can cause measles, mumps and canine distemper. Experts say the findings are based on electron microscope images, which aren't definitive. Other tests such as genetic profiling are needed to confirm the findings.

Researchers in the U.S. have seen a coronavirus, one of the viruses that causes the common cold. They say SARS could be caused by a combination of viruses. It is too early to tell. Microbiologists in Hong Kong believe they have identified a test to diagnose SARS, which they are perfecting.
What are the risks?

Health officials say the risks are low for most Canadians. "If someone is in close contact with one of the probable cases they are at greater risk," said Dr. Colin D'Cunha, Ontario's Public Health Commissioner, on March 23. "For members of the general public, the risk appears to be otherwise slim and near zero." He added there is no evidence it spreads through casual contact.

Probable cases are people showing symptoms who have recently travelled to Asia or have been in close contact with other SARS patients. Suspect cases show symptoms, but have no travel or contact history. Dr. Jay Keystone, a travel and tropical disease specialist with the University of Toronto, said close contact is needed with someone who is infected. Ninety per cent of cases have been in unprotected health care workers, who have had direct contact with respiratory secretions (sneezes, coughs, nasal fluids) of SARS patients. He added SARS is moving quickly around the world because of air travel, but it isn't spreading rapidly within the community.
Where did SARS originate?

WHO has reported hundreds of cases in Hong Kong and Vietnam since February. An outbreak of pneumonia with similar symptoms struck Guangdong province in China last November and was brought under control in mid-February.

Doctors in Hong Kong are focusing their investigation on a hotel where seven guests contracted the ailment from a Chinese professor and carried it to Vietnam, Singapore and Canada. No one knows how the disease spread in the hotel. Health officials have speculated the professor sneezed or coughed by an elevator. One expert pointed to the hotel's air conditioning system, but none of the hotel workers have become sick.
What does the Toronto quarantine mean?

Several health care workers at Scarborough Grace Hospital in Toronto's east end were exposed to SARS before they knew to take precautions. Access to the hospital has been restricted. As a precaution, on March 26 Toronto's Medical Officer of Health recommended everyone who has visited Scarborough Grace Hospital since March 16 should stay in their home for 10 days from the time of the visit. Their family members may go to work or school, but must wear a mask when at home and in contact with those who are at risk of infection.

Hospital visitors are unlikely to have had direct contact with SARS patients and they have "a very low risk of exposure." Health officials said isolating cases is a priority, and the extraordinary measures are the only way to manage the disease and protect people. Anyone who may be a contact of a SARS case through Scarborough Grace and has symptoms or concerns can call the Toronto Public Health Hotline at (416) 338-7600 for further information.

Infected health workers and their family members have been quarantined, meaning they cannot go to school or work, buy groceries etc.

What are governments doing?
On March 25, SARS became a reportable, virulent, communicable disease in Ontario. The change allows public health officers to quarantine infectious people and their family members for up to 10 days to track the disease and prevent it from spreading.

The Ontario government has set up an around-the-clock command centre to co-ordinate information on the spread of the virus. People with general questions about SARS can call Telehealth Ontario at 1-866-797-0000 to speak to a registered nurse.

Canadian, provincial and local health officials are working together to enhance surveillance and look for additional cases, including those arriving on international flights. Sick passengers are assessed in separate rooms and promptly taken from the airport to hospital. Laboratories around the world, including the National Microbiology Laboratory in Winnipeg, are trying to determine the origins and cause of the disease.

On the other side of the Pacific, health officials in Singapore have quarantined more than 700 people who may be at risk. In Hong Kong, officials have called for all schools to be disinfected. Children with infected family members must avoid classes for a week.

What about travel?
On March 25, Health Canada upgraded its travel advisory and urged Canadians planning trips to Hanoi, Vietnam; Hong Kong; and Singapore to defer travel for the time being. "Given the uncertainties of the current situation, Health Canada believes it is prudent to await the outcome of national and international control measures before undertaking travel to these destinations," the advisory said.

Health Canada also warns travellers that health care services may not be up to handling SARS. For example, the only adequate hospital in Hanoi has been closed. Health alert notices are handed out to all passengers arriving on international flights from all destinations other than the United States. The notices tell passengers to be on the look out for symptoms that may develop within 10 days of arriving, such as fever, cough, and breath. If so, they should seek immediate medical attention. Hospital staff are taking travel medical histories.

In Hong Kong, airplane passengers have become ill. The World Health Organization said on March 25 that air travel is safe, but its scientists are looking closely at the growing number of cases in Hong Kong to see whether it is more contagious than thought.

"We would want to be sure that it was people sitting next to that person and not the ventilation system in the airplane which was spreading the disease," said Dr. David Heymann, head of communicable diseases at WHO. "We have no evidence of the latter right now."
Health investigators have followed thousands of passengers who flew with SARS-infected travellers and did not become sick.

How are patients being treated?
In Toronto, those suspected of having SARS are being quarantined in rooms with a controlled air supply, said Dr. Simor. Anyone who goes into the room wears a special mask to filter out pathogens, as well as gloves and a gown. Hand washing is also important.

In Toronto, Simor said, patients are being treated with broad-spectrum antibiotics (in case it is caused by an as-yet unrecognized bacteria), and two antiviral drugs. One antiviral drug fights influenza and the other is a broad-spectrum antiviral that may have helped patients in Hong Kong.

SARS Cases as of March 27, 2003:
Total number of cases: 1408 (includes deaths)
Total number of deaths: 53

CANADA
Ontario: 28 probable cases including 3 deaths. To date, all cases have occurred in close family contacts of travellers returning from Hong Kong, or in heath care workers who have cared for these cases.
British Columbia: One person has been hospitalized with SARS after returning from travel in southeast Asia.

REST OF THE WORLD
China - Province of Guangdong 806 probable cases including 34 deaths.
France 1 probable case
Germany 4 probable cases
Hong Kong 367 probable cases including 10 deaths.
Italy 2 probable cases
Ireland 2 probable cases
Singapore 78 probable cases including 2 deaths
Switzerland 2 probable cases
Taiwan 6 probable cases
Thailand 3 probable cases
United Kingdom 3 probable cases
United States 45 suspect cases
Vietnam 58 probable cases including 4 deaths
Source: World Health Organization, Health Canada and Ontario Ministry of Health