You can be infected with the virus by coming into close contact with an infected person. Contact with exhaled droplets after someone coughs or sneezes, and bodily secretions from an infected person appear to be the most likely sources of infection. The virus can survive for a period of about three hours on surfaces touched by an infected person, such as desktops, doorknobs or elevator buttons. The World Health Organisation still believes that the disease is not airborne. There is also no evidence mosquitoes can spread Sars, nor is it likely.

WILL THE DISEASE EVENTUALLY BURN OUT, LIKE THE FLU?

Medical opinions are divided on whether the new virus will behave like the flu and eventually just burn out, or whether it will keep going until there are more people infected than not.

One expert in respiratory medicine believes if the virus acts like an influenza virus, which spreads rapidly during spring and disappears with arrival of warmer weather, it may burn out. He said a number of his colleagues believed the Sars virus may also be losing some of its potency as it moves from one generation of patients to the next.

However, other medical experts say the theory that the virus will disappear by itself is not based on any hard evidence. 'That theory is more a matter of wishful thinking. We do not yet know exactly what the virus is and we cannot say whether it will behave like an influenza virus,' one said.

The doctor said under usual circumstances when a disease strikes, the community builds up immunity to it gradually, as an increasing number of people are affected. 'For the disease to keep spreading the number of susceptible people has to be greater than the number of infected cases

'But in the case of this virus we really cannot afford to have hundreds of thousands of people infected before the disease dies down. I hope an increased level of awareness and the precautionary measures that are being taken will halt the progress of the disease.'

HOW INFECTIOUS IS IT?

Sars appears to be less infectious than influenza. The WHO believes the virus is not highly contagious when protective measures are used, and the percentage of cases that have been fatal is low. At the time of printing, 708 patients have been admitted to hospitals in Hong Kong with atypical pneumonia since March 12 - 89 have already recovered and have been discharged. A total of 16 patients have died, the majority of whom were elderly or suffering from other illnesses which had weakened their immune system. In total, 1,804 people have been infected worldwide; 62 have died.

The incubation period is estimated to range from two to seven days, with three to five days being more common. Isolated reports have suggested an incubation period of up to 10 days.

IS THERE A CURE?

The current treatment, which has been used effectively, is a combination therapy of the antiviral agent ribavirin (a broad spectrum antiviral drug) and steroids. No vaccine has yet been developed. Women who are less than 28 weeks pregnant should not receive the treatment as there is a risk of deformity to the unborn baby.

YOUR HEALTH

HOW DO I KNOW IF I HAVE THE VIRUS?

Symptoms include a fever of over 38 degrees Celsius, a cough, headache across the forehead, breathlessness and sore throat.

Experts say the infection takes between two to seven days from the time of transmission before you show symptoms. The first sign in most cases is the sudden onset of a high fever which burns you up then half an hour later, leaves you shivering.You feel so awful it is hard to carry on and the rise in temperature often gives you a thumping headache. Another sign is a dry, hacking cough which is sometimes painful but does not bring up phlegm as opposed to the cough associated with Hong Kong pollution which doctors call a productive cough which does bring up phlegm.

Other things to look out for are muscle aches and skin sensitivity which makes it hurt to have a shower, aching joints, and shortness of breath even if you have not been doing anything physically exerting.

Less common symptoms are a rash and/or diarrhoea.

WHAT DO I DO IF I HAVE THESE SYMPTOMS?

Don't panic. See your doctor or visit a hospital as quickly as possible. You need to be carefully examined not only so you get the best treatment but to prevent it spreading to others. Your doctor or hospital is likely to send you for an X-ray to confirm the diagnosis. A laboratory test has been developed to detect the coronavirus in patients, but these tests are only carried out in the government laboratory and two universities. The test serves to confirm suspected cases of atypical pneumonia.

IF I GET IT, WILL I SURVIVE?

According to the World Health Organisation of the more than 1,500 people who have contracted atypical pneumonia, approximately three per cent have died. According to WHO findings, most of the fatalities were suffering from other medical conditions which had weakened them in the first place. In most cases, patients begin to recover from the virus after 5-7 days. But in a percentage of cases the infection deteriorates into a severe condition that cripples the lungs. These people need artificial ventilation while they fight the disease, and some of these are the ones who have died.

WHAT DO I DO IF A FRIEND OR FAMILY MEMBER HAS BEEN INFECTED?

If you think you may have had contact with an infected person, stay calm. It is important for your own health, and in consideration to others, that you wear a face mask and seek medical advice. Early diagnosis will also greatly improve your chance of a speedy recovery.

People who have had close contact with patients suffering from the disease will be advised on what to do by health authorities. They will be required to stop work, remain at home and report daily to surveillance centres for 10 days. If you are required to stay at home, clean furniture, surfaces and toys properly with a solution of 1 part bleach to 99 parts water.

If you are quarantined at home, the health authorities will provide assistance and advice. There is no need to 'panic-buy' in anticipation of this as many supermarkets do provide home delivery and supplies are not about to run dry. However, it is sensible to keep your cupboards well stocked.

Hard as it may be to stay away from loved ones in hospital, it is advisable to avoid visiting patients with atypical pneumonia. You can still maintain regular contact by telephone.

PREVENTIVE MEASURES

WHAT PRECAUTIONS SHOULD I TAKE?

Stay informed, stay calm and follow the advice of qualified health authorities or your doctor.

As a general precaution wear a face mask, but make sure you wear it correctly and discard it in a plastic bag when it becomes damp or soiled.

Where possible avoid confined, overcrowded spaces such as lifts, the MTR, buses and planes.

Give your immune system a chance to fight it off by getting plenty of sleep - aim for eight to ten hours of sleep a night.

A good diet will also boost your immune system, which means eating plenty of fresh fruit and vegetables, while cutting back on processed foods. Medical experts recommend a range of basic supplements to build your immune system. These include Vitamin C, Vitamin A (Cod Liver Oil for children), Zinc and Echinacea. Please speak to your doctor about dosage.

Now is also a good time to start an exercise programme but it is best to look to the outdoors for activities rather than a gym where surfaces can be infected. Take a 30-minute walk in a relaxing environment or take the stairs if you are concerned about being stuck in a lift with people.

Stop smoking and drink no more than two standard alcoholic beverages per day

Personal hygiene is important, so be meticulous about frequent hand-washing and disinfecting your homes and offices at least once a day.

Wearing surgical gloves is as much a part of infection control as using a mask but it is more effective to be aware at all times that the infection can be passed by hand, so you should be washing your hands or cleaning them with antibacterial wipes every one to two hours. Liquid soap is preferable to bar soaps, which can become an agent of infection if shared by different people. Use disposable towels to dry your hands and do not share towels.

Every time you think of rubbing your eyes or touching your face, restrain yourself or use a tissue.

Tissues, masks and other things that come into contact with your mouth, eyes and nose should be placed in plastic bags and disposed of.

Pregnant women

Women less than 28 weeks pregnant infected with the virus cannot use the steroid-based treatment being offered because of the risk of deformity of the foetus. The advice to pregnant women is to avoid crowds, poorly ventilated places and public transport until the virus disappears. Be meticulous about cleaning all surfaces in your home, your eating utensils and about hand-washing. In selecting a face mask, the N95 mask (which is also used for air-borne viruses) may not be the ideal choice for pregnant women because the fibres of the mask are so thick it is more difficult to draw in air. Wear gloves or carry hand-wipes (if you have another child you'll no doubt have these on you at all times) and clean your hands every time you consider putting them near your mouth. Whatever is dangerous for the rest of society is doubly dangerous for the pregnant mother because she is nurturing another life.

Children

The decision to close schools was based on concerns over the rapid spread of the virus between children. It is up to parents to decide whether allowing their children to play with other children poses an unacceptable level of risk. However, well-ventilated and outdoor areas are definitely the preferred option for such play-time. Also, tell your children never to touch or swap their masks with friends.

Unless you are taking your child into crowded areas, hospitals or clinics or on public transport there is probably no need to worry if your child refuses to wear a face-mask. It may be a blessing if children refuse to wear masks out - tell them they won't need to if they stay at home.

It is important for parents not to convey their own anxiety to their children. Use your time at home together for quality playtime and working together on homework. Children's toys and surfaces in the home which they come into contact with should be regularly cleaned and, after going out into a 'high-risk' area, their clothes should be changed and washed.

WHAT SHOULD I DO IN THE OFFICE?

The office should be well ventilated, and windows opened from time to time. Air conditioners should be well maintained and cleaned regularly. Office furniture and equipment should be kept clean.

If feeling unwell, employees should report this immediately and seek early medical advice. They should not go to work. According to the labour law, you are entitled to take paid sick leave.

WHAT SHOULD I DO AT HOME?

Wipe furniture, door handles, surfaces and appliances such as telephones, remote controls, and kettles at least once a day with a towel soaked in diluted household bleach (adding 1 part of household bleach to 99 parts of water). Use a second cloth or piece of towel soaked with water to rinse the area.

Do not share towels or eating utensils. Do not pick from a shared plate of food with chopsticks or forks, but dish out individually.

Maintain good indoor ventilation by opening windows rather than using the air-conditioning, which will circulate contaminated air.

HOW DO I WEAR MY FACE MASK?

An ordinary surgical face mask is effective in preventing the spread of droplet infections. You should wear a face mask if you have a cough or other respiratory symptoms. People who have close contact with confirmed cases of atypical pneumonia, carers and those visiting sick people in hospitals should also wear a face mask.

If you are charged more than about $4 for a simple, paper surgical mask, you are probably paying too much, although expect to pay more for higher-quality masks, such as the N95 face mask, which costs around $10. Experts say both are effective in preventing infection of water-borne viruses, whereas the N95 mask is also used for airborne viruses. As this mask has thick fibres, it makes it more difficult to suck in air so it may not be ideal for those who have asthma, breathing problems or for women who are pregnant.

In general, a surgical face mask needs to be changed daily. However, replace the face mask immediately if it becomes worn or damaged. It is important to note that masks lose their effectiveness once the surface is wet.

Before putting on a face mask, wash your hands. The mask should fit snugly over the face. If the mask has a metallic brace, this should be fixed securely over the bridge of the nose to prevent leakage.

Once you have put on your face mask do not touch it or remove it and then replace it because you risk spreading any virus that may be on the outside of your mask.

To dispose of the face mask, place it in a plastic bag and tie it properly before putting it into a rubbish bin.

HOW DO I COPE WITH THE STRESS THAT

THIS IS CAUSING ME AND MY FAMILY?

The best way to get over feelings of anxiety and depression is not to overreact, stick to the facts and focus on being positive, according to counsellors.

'If you decide to stay home because going to a restaurant poses an unacceptable level of risk to you, then do something nice, like treating yourself to a candle-lit dinner. Pop the cork on a good bottle of wine you've been saving for a special occasion,' says David Bailey, the director of St John's Counselling Service.

Mr Bailey's advice is for people to arm themselves with the facts - seek advice from their family doctor and talk about their concerns.

He says living in denial is an equally unhealthy attitude. 'Denial doesn't work well when you're in a place where everyone is wearing face masks. It is also a source of conflict between those who wear face masks and those who do not. What we should be doing is carrying on with our lives as much as possible while taking every possible safety precaution,' he said.

Chinese University psychiatry professor Lee Sing agrees. 'People lose sight of the fact that all viral diseases are basically preventable and that more than 90 per cent of those who did have the illness have been cured,' he says.

OUT AND ABOUT

IS PUBLIC TRANSPORT SAFE?

You are at risk on all forms of public transport because it is impossible to avoid being less than a foot away from the next person. If you must use public transport, wear a mask or cover your mouth and nose and, if possible, open a window.

The Department of Health has advised public transport companies and operators to ensure good ventilation and cleanliness in the vehicle compartment and station facilities. A number of bus and railway operators have been handing out face masks to commuters.

SHOULD I AVOID FLYING?

Physician and Post columnist Dr Margaret Cheng says flying should be avoided unless absolutely necessary. 'The number of people infected at Amoy Gardens has made people consider that the virus could be airborne,' she says, 'and an aircraft has highly recirculated air. First ask yourself if you really have to make this trip.'

Dr Cheng says passengers should wear properly fitting masks at all times, avoid physical contact with others, and not eat the meals because the virus could be passed on through handling.

IS IT SAFE TO EAT AT RESTAURANTS?

It is possible for the virus to be passed on through food, cutlery and utensils, if these are handled by an infected person. However, if you eat in a restaurant where the tables are well spaced and you are confident hygiene is good, you should be fine.

The Department of Health has issued guidelines to all food premises, including the cleaning, inspection and maintenance of all ventilating systems in their premises, providing customers with tableware for individuals, including additional chopsticks or spoons for the common serving of food.

CAN I STILL PLAY SPORTS?

Non-contact sports outdoors are probably a good thing to do as they strengthen your immune system. Hiking, jogging, cycling, skateboarding and tennis are considered beneficial.

There is no evidence of transmission through swimming but as a precautionary measure, public pools are closed until April 6. The area around swimming pools and changing rooms offer too many chances for people to come into contact with each other's secretions. The same goes for changing rooms and surfaces in gyms.

HOTLINES - WHO TO CALL FOR HELP

Hotline for people who have come in contact with infected persons from Amoy Gardens, Prince of Wales Ward 8A and Metropole Hotel: 187 2222

Department of Health (pre-recorded health education hotline) 2833 0111

Department of Health hotline for general advice (during office hours) 2961 8968

Department of Health hotlines for notification of infections:

- Hong Kong 2961 8729

- Kowloon 2199 9149

- New Territories East 2158 5107

- New Territories West 2615 8571

Social Welfare Department Hotline : 2343 2255

Social Welfare Department (general): 2340 8471

Social Welfare Department (financial support) 2892 5202

Education and Manpower Bureau Hotline : 2892 2352

Evangelical/Lutheran Church Social Services 3124 7845

Youth Line (Hong Kong Federation of Youth Groups) 2777 8899

Children's Hotline (Boys and Girls Clubs Association of Hong Kong) 2520 6800

Sources: Compiled from personal interviews with medical experts, information from the Department of Health, World Health Organisation, and information supplied by Post columnist Dr Margaret Cheng.