Severe Acute Respiratory Syndrome (SARS)

A brief history

Outbreak source

The SARS outbreak is thought to have originated in the Guangdong province of southern China in mid-November, last year. Over 300 people were taken ill with a new infectious disease, and 5 people died. On 21 February this year, a doctor who had been treating the cases in Guangdong travelled to Hong Kong for a wedding, where he fell ill. He is believed to have infected several guests who were staying in the same hotel. After being admitted to hospital, where he also passed the disease on to medical staff, he later died of the infection.

Out of Hong Kong

It is thought that the disease then spread outside Hong Kong with the infected hotel guests. These included Singaporeans, Canadians, and a Chinese-American businessman. The businessman travelled from Hong Kong to Hanoi, Vietnam, in late February and infected hospital workers there when he fell ill a few days later. The World Health Organization (WHO) infectious disease specialist, Carlo Urbani, was asked to advise in Vietnam, and called the disease Severe Acute Respiratory Syndrome. Due to his close work with the SARS patients, Carlo Urbani himself became infected and died 29 March.

On 15 March, the WHO issued emergency travel advice, and warned airline staff and doctors to look for the symptoms of SARS in travellers from affected areas. Fears began to arise that the disease was the work of bioterrorists.

Potential cause identified?

In mid-March, Hong Kong scientists claimed that they had found paramyxovirus in patients with SARS. This family of viruses is responsible for measles, mumps, pneumonia and the common cold. Then on 22 March, Canadian scientists at the National Microbiology Laboratory in Winnipeg announced that they had found metapneumovirus (a member of the paramyxoviridae family) in 6 out of 8 cases of SARS.

Teamwork required

At this time, WHO began co-ordinating an international team of laboratories that worked together to find the cause of the disease. The group identified it as coronavirus, not paramyxovirus. Microarray analysis on samples from SARS patients, by Joe DeRisi at the University of California, San Francisco, indicated that coronavirus was the cause of the disease. He observed, in particular, a strong link between the SARS virus and two other coronaviruses: avian infectious bronchitis virus and a bovine coronavirus. There are two already known coronaviruses, 229E and OC43, which have been known for many years to cause between 5 and 30 % of common colds in humans, and can also cause intestinal infections. In birds and other mammals, however, it can cause very serious infections. On 24 March it was announced to the world that the likely cause of SARS was a new coronavirus.

By 2 April, WHO and the UK's Department of Health (DOH) had strongly advised against travelling to Hong Kong and Guangdong.

Genome of SARS agent revealed

In mid-April, Canadian scientists at the Michael Smith Genome Services Centre and a group from the US Centers for Disease Control and Prevention (US CDC) both sequenced the genome of the virus most linked with SARS. The results confirmed the cause as a coronavirus different from all those previously known.

Test for SARS

A German biotechnology company, Artus GmbH, made a new diagnostic kit available for SARS testing on 15 April. The kit was designed using the coronavirus genomic sequence, and uses the polymerase chain reaction (PCR) to detect the presence of the virus in suspected cases much earlier than other methods in use. These methods rely on the production of antibodies to the virus by the immune system much later on in the infection.

Underestimated numbers of SARS infection

On 16 April, WHO claimed that China was vastly underreporting cases of SARS. The Chinese government said that the discrepancy between their reported figures and WHO's estimated figures was due to a 'reporting problem' between military and government hospitals. A Chinese military doctor then boldly revealed that hundreds of SARS cases were being covered-up. Four days later, China's Health Minister and Beijing's mayor were both sacked over the handling of the SARS outbreak. China then admitted that the outbreak in Beijing was ten times worse than previously stated. By 20 April thousands of people in the worst affected areas had accepted a voluntary quarantine.

Coronavirus link weak

Scientists in Hong Kong found coronavirus in 9 out of 10 SARS cases. However, scientists from the Canadian National Microbiology Laboratory, claim that the link between SARS and the coronavirus is weak, as they found the coronavirus in only 4 out of 10 people suffering with SARS.

Due to the increasing number of SARS cases there, Toronto was added to the WHO's list of destinations to avoid on 23 April.

Severe symptoms

Many researchers now believe that the main causative agent in SARS infections is a new form of coronavirus, and that co-infection with metapneumovirus worsens the symptoms, explaining why some cases are far more severe. An article published in March this year by a group from the University of Liverpool, suggested that an infection of human metapneumovirus in patients that were already suffering with respiratory syncytial virus (RSV) made symptoms of RSV worse.

Coronavirus

Coronaviruses are enveloped, single-stranded RNA viruses. They have a genome of approximately 30 kilo-bases, the largest of the RNA viruses. This family of viruses is named for their crown-like appearance, which is due to an array of surface projections on the viral envelope. Typically they have a narrow host range and they replicate in the cytoplasm of the host epithelial cells.

Latest fears

Now that scientists are beginning to understand the disease a little more, new fears about SARS are beginning to spread. These include the potential emergence of asymptomatic spreaders. These are people carrying SARS, but showing no symptoms of the disease. They could have a serious impact on the number of cases. Also of concern are cases of tertiary infection. These are infected people without a direct link to SARS exposure.

Although bioterrorism has been ruled out as the source of the outbreak, there are still a number of conspiracy theories about the source SARS.

Weekly update

Week ending 29 June 2003. This week, celebrations started as the WHO lifted its travel warning on Beijing and declared Hong Kong free of SARS. The news buoyed the travel and tourism industries, and Cathay Pacific announced plans to return to its full, pre-SARS timetable.

Scientists believe that SARS was defeated by good hygiene and the rise in temperature brought on by summer. Quarantines are also thought to have aided the efforts to stop the disease.

Heineken, the brewing company, blamed SARS, the war in Iraq and the general economic slowdown for the fall in its shares.

The figures (from WHO) on 27 June 2003 put the total number of probable cases of SARS worldwide at 8450, with the number of deaths at 810.

Week ending 22 June 2003. This week, SARS has caused many expatriates based in the Far East to leave the area. Some are checking their medical/health insurance to make sure that they are properly covered.

WHO declared that SARS outbreak had been brought under control, causing a surge in the Asian indices. The epidemic will be announced over in Hong Kong, after health officials confirmed that they had no new suspected cases.

However, the aviation industry is still struggling. SARS, along with 11 September, the Iraq war and slow economic growth, has been blamed for the loss of about 20,000 jobs. Singapore Airlines have seen passenger numbers fall by 50 %, and have had to lay-off more than 400 staff.

The Special Olympics began this week, and included athletes from five Far East countries that had previously been banned from attending due to SARS.

Finally, holidaymakers are set to profit from a price war. Travel agents are promising to undercut each other in an attempt to entice people to begin travelling again.

The figures (from WHO) on 20 June 2003 put the total number of probable cases of SARS worldwide at 8461, with the number of deaths at 804.

Week ending 15 June 2003. This week, Stagecoach sold its Hong Kong Citybus business to a local bus operator, after revenues struggled in the wake of the SARS outbreak. Meanwhile, Motorola announced that handset sales in Asia had been hit by SARS, and that they expected profits to fall below expectations.

Chubb, one of Britain's oldest security companies, has agreed to be taken over by United Technologies Corporation, a US conglomerate. Chubb had earlier warned that its profits would be affected by the SARS outbreak.

Texas Instruments, the world's biggest maker of mobile phone chips, blamed SARS for a slump in demand and a drop in share price.

British Midland listed SARS as one of a number of reasons for the decision to cut staff numbers. One third of its workforce are to lose their jobs over the next 3 to 4 years. Asian airlines are also struggling. Both Cathay Pacific and Singapore Airlines are suffering due to drops in passenger numbers.

SARS is beginning to affect the Chinese economy, where export growth is expected to fall by more than 50 % in the next few months.

On the bright side, temporary staff have been needed at 3M in Newton Aycliffe, Durham, wiping out unemployment there. The company, who make surgical masks, have seen orders rise by 8 million in the last 2 months due to SARS, and are currently operating 24 hours a day, 7 days a week.

The WHO said that the number of new SARS cases worldwide suggested that the epidemic may be coming to an end.

The figures (from WHO) on 13 June 2003 put the total number of probable cases of SARS worldwide at 8454, with the number of deaths at 792.

Week ending 08 June 2003. Early in the week, China announced that for over 24 hours it had no new cases of SARS to report. Meanwhile, four more deaths were being investigated by health officials in Toronto to establish whether they were caused by the disease. These latest deaths could bring the total of SARS-related deaths in Canada to 31.

Chinese authorities identified the person believed to have started the SARS epidemic. The cook, Huang Xingchu, prepared wild animal dishes in a restaurant in Shenzhen. He survived the infection, but passed it on to others at Heyuan hospital were he was admitted in December last year. Mr Huang has apologised for spreading the virus.

Moscow expelled over 500 Chinese and Vietnamese from Russia as part of its measures to prevent the spread of SARS.

The G8 summit, held in France, agreed to improve international co-operation against new epidemics, such as SARS.

Some experts believe the domestic cat could be a potential reservoir for SARS. WHO is to investigate which species of animals could act as reservoirs. In particular, it plans to look at animals that come into regular contact with humans, as these could be a source of further outbreaks.

Ireland lifted its ban on athletes from Hong Kong attending the Special Olympics this month.

A hospital in Ontario, Canada, has quarantined mothers and newborn babies, after a health worker on the ward developed SARS. The employee had previously been exposed to the virus, but symptoms of SARS did not appear until after the standard 10-day quarantine.

Finally, an official from WHO announced that the SARS outbreak was over its peak.

The figures (from WHO) on 06 June 2003 put the total number of probable cases of SARS worldwide at 8404, with the number of deaths at 779.

Week ending 01 June 2003. Canada added another 20 more possible new cases of SARS to those announced last week. Toronto, where the new cases have been, has been restored to the WHO list of SARS-affected areas. This comes only twelve days after the city was removed from the list. More than 1000 people have been quarantined to help stop the spread of the disease. Since the announcement of its new cases of SARS, Toronto fears that WHO may issue another travel warning to the city.

In Taiwan, a hospital laundry worker is blamed for the SARS epidemic there. He developed the disease, and went undiagnosed for 6 days, directly infecting 81 other people and potentially thousands more.

As it had been 20 days since the last reported case of local transmission of infection, WHO removed Singapore from its list of SARS-affected areas.

WHO removed its warning against non-essential travel to Hong Kong, and the Tourist Board there are planning a promotional campaign to help the tourism industry, which was severely hit by the SARS outbreak.

The Republic of Ireland's Department of Health withdrew its request that athletes from SARS-affected areas should not travel to the Special Olympics, to be held there in June. As a precaution, however, they will quarantine athletes from these countries for 10-days prior to the games.

The men's junior world basketball championships that were to be held in Malaysia, 10-20 July, are being moved to Greece because of fears of SARS.

Finally, psychiatrists in Hong Kong are seeing recovered SARS patients suffering with hallucinations, manic behaviour, rapid mood swings and memory loss. The steroids used in many cases to fight the virus could have caused these early signs of potentially irreversible brain and nerve damage.

The figures (from WHO) for 31 May 2003 put the number of probable cases of SARS at 8360, with the number of deaths at 764.

Week ending 25 May 2003 Two more hospitals were shut in Taiwan as SARS spread to an island offshore, and a doctor from Taiwan caused panic in Japan when he became feverish whilst on holiday there. The doctor had unknowingly contracted SARS from a patient he had been treating. Chinese and Taiwanese visitors have since been refused reservations in Japan over fears of contracting the illness.

Alan Milburn, the UK Health Secretary, stated that WHO should carry out a review of every country to assess how prepared they are to deal with outbreaks of new diseases. In addition, he wants international law to be strong enough to ensure that demands by WHO would be carried out by all countries.

British Airways announced they might be forced to cut jobs as SARS, along with terrorism and the war in Iraq, continue to affect business.

Travel bans in China that have been imposed by the government have caused problems for Griffin Mining, which has led to a drop in share price for the company. However, China's manufacturing industry remains buoyant despite SARS.

Hu Jintao, the Chinese president, is leading by example to calm fears of SARS. Ahead of his upcoming international state visits he is having chest x-rays, blood tests, temperature readings, and injections to boost immunity.

The warnings against travelling to Hong Kong and Guangdong were lifted by WHO, as the SARS outbreak in these areas appears to be under control.

The source of the SARS virus was revealed this week to be the masked palm civet. This cat-like mammal is a related to the mongoose, and is regarded as a delicacy in Guangdong province where the outbreak first originated. Microbiologists at the University of Hong Kong checked large numbers of domestic and game animals to try to find the cause of SARS. It is believed that the virus jumped to humans as they raised, slaughtered and cooked the animals, rather than from eating infected meat. Virus samples very similar to coronavirus were isolated from faeces and respiratory fluids of 4 individual civets. It is hoped this information could help prevent further outbreaks through controlling the sale and slaughter of these animals in China.

Canada announced it might have at least 20 new cases of SARS, and hundreds of people have been advised to go into 10-day quarantine. A hip-replacement patient in Toronto is thought to have infected neighbours, health workers, and other patients before she was diagnosed with the illness. Only last week the city was removed from the WHO list of areas with recent local transmission.

Athletes from SARS affected areas are to be banned from attending the Special Olympics being held in Ireland in June this year. The ban on competitors from China, Hong Kong, Taiwan, Singapore and the Philippines is there to protect Irish healthcare workers, as this group has been hit hard by SARS infections throughout the world. With the latest cases, it is now feared that Canada may also be added to the list of banned countries.

Finally, an article published in The Lancet claims that SARS came from outer space. Professor Chandra Wickramasinghe, from the Cardiff Centre for Astrobiology, believes that large amounts of microorganisms fall to Earth every day, and that these are the cause of many plagues that have affected our planet.

Week ending 18 May 2003. This week, as the number of cases of SARS in China passed 5000, health workers took to the streets of Guangzhou in southern China in an attempt to crack down on the regular practice of spitting. Also targeted and fined, are those who drop rubbish, cigarette butts or chewing gum, and those who urinate in public places. In an attempt to halt the spread of the disease, many Chinese cities have started such campaigns to raise awareness of public hygiene.

WHO announced that the number of SARS infections was not dropping in China, despite reductions in cases in Beijing. The Chinese People's Liberation Army has been seriously affected with about 8 % of Beijing's cases being military staff. China's Supreme Court has ruled that anyone who breaks quarantine or spreads SARS intentionally may be jailed for at least 10 years, jailed for life, or executed.

In Russia, passengers on a flight from China were sent back after they refused to have their temperature tested as a diagnosis of SARS.

Also this week, the 'probable' number of Britons to have caught SARS was reduced from 6 to 4, and later the first confirmed UK case was reported. In Canada, WHO announced that SARS was under control and no longer spreading.

An experimental drug, developed for the common cold, is likely to be also tried on SARS patients. The drug was designed to stop the enzyme responsible for viral replication in rhinovirus (a cause of the common cold). The corresponding enzyme in coronaviruses is slightly different from that in rhinoviruses, but researchers who designed the drug believe it should be tested against SARS. The drug could also be modified to treat SARS specifically.

Economically, SARS is still having a major impact. Air Canada has grounded 40 planes due to low passenger numbers caused by SARS fears. SARS is also affecting the copper industry. China is the biggest consumer of copper, and fears about demand for the metal in China have reduced the price of shares of copper producing companies. The Hilton hotel group blames SARS, as well as the war in Iraq, for the drop in hotel bookings that has lead to a drop in the company's profits.

The source of the SARS virus is still a mystery. Early on in the outbreak it was believed that the virus may have come from pigs or chickens and mutated to infect humans. However, doubt has been cast on this idea as recent attempts to infect pigs and chickens with the SARS virus have failed, according to WHO.
Finally, there are rumours that Hollywood is considering making a film about the SARS outbreak.

Week ending 11 May 2003. There are now over 30 countries worldwide with reported cases of SARS. This week, the British aid group Voluntary Service Overseas (VSO) is reported to have ordered 120 volunteers to leave China because of SARS. As hundreds of hospital staff in Beijing quit for fear of catching SARS from the patients, the government in China announced that the city's elementary and middle schools are to stay closed for another 2 weeks.

WHO announced the results from experiments showing the survival times of the SARS virus. It can survive for up to 48 hours on plastic surfaces, for at least 2 days in faeces, and at least 24 hours in urine. The results also show that in diarrhoea, which is less acidic than normal stools, the virus can survive for 4 days. The virus was also shown to lose its ability to infect after exposure to a number of different commonly used disinfectants. WHO recommended postponement of all non-essential travel to Hong Kong Special Administrative Region, Beijing, Guangdong and Shanxi provinces of China. It later extended this advice to include Taipei, Taiwan and Tianjin and Inner Mongolia, China.

Further measures to combat the spread of SARS in China include the quarantine of 10,000 people in Nanjing, and patrols in Beijing. Despite these tough measures, WHO announced that SARS was still out of control in China.
Research published in The Lancet suggested that in Hong Kong the SARS virus is killing 1 in 5 people. Those aged over 60 were most at risk, with over 50 % dying, and in those under 60, the death rate was about 7 %.

After European health ministers agreed to drop plans for large-scale screening of passengers arriving from countries most affected by SARS, Italy announced that it may introduce border controls for high-risk travellers.

After 20 suspected cases, Russia confirmed its first case of SARS. In response, the government closed Chinese border crossings and restricted commercial flights to and from China, Hong Kong, and Taiwan.
A poll by the British Medical Association News found that UK doctors don't think they would cope with a SARS outbreak. It also found that 73 % of GPs thought that SARS should be made a notifiable disease.

Studies in The Lancet show that the SARS virus is not mutating as expected. In other epidemics, the cause of disease can mutate to a more benign form, which does not appear to be happening with SARS.

In a desperate attempt to ward off SARS, the people of Hong Kong are trying a variety of 'cures'. These include drinking alcohol; in particular whisky, smoking 30 cigarettes a day, and drinking the fermented milk drink Yakult.

Finally, despite there being no scientific evidence for it, fears are growing in China that pets are hosts for SARS. This has lead to extermination patrols killing hundreds of cats and dogs.

Week ending 4 May 2003. This week, WHO have lifted their travel warning for Toronto and have declared Vietnam the first country to contain the SARS outbreak. They also announced that the disease had peaked in most areas except China.

China has sacked another 16 officials over handling of the outbreak, and Beijing's acting mayor has said that the hospitals are unable to cope with the high numbers of SARS patients.

News from India increases the number of cases there to nine and health officials in Britain are expecting more cases of SARS in the UK before the outbreak subsides.

To protect Britain from SARS, airline passengers may be screened. In addition, new medical staff taking up posts in the UK, who come from affected areas, will be asked to postpone their starting date for 2 weeks after arriving in the country.

The Republic of Ireland's health boards are organising quarantine centres to help deal with probable cases of SARS.

Finally, a report in The Lancet from a team at the Chinese University of Hong Kong suggests that SARS is less serious for children. They found that younger children had milder symptoms than teenagers and adults, and that they regained full health much more quickly.

Symptoms

SARS is an atypical pneumonia, with symptoms that are 'flu-like. These include high fever (greater than 38 °C), aching muscles, chills, sore throat, headache, dry cough, shortness of breath, breathing difficulties, and in a number of cases diarrhoea. The official death rate from SARS was initially about 4 %, higher than many respiratory diseases. Lately, this has been estimated at closer to 10 %. The incubation period is thought to be 2-10 days, and the infectious period is not thought to start until the onset of symptoms. Antibodies to SARS have been detected in patients from about 10 days after the start of clinical symptoms.

Treatment

There is currently no cure for SARS. Some patients have been treated with non-specific antiviral drugs to combat the virus. In addition, many have been given steroids to reduce the severe inflammatory response to the infection. Others have been put on life-support in the hope that their own immune system will combat the infection.

In Hong Kong, some severely affected patients were treated with antibodies taken from recovered patients.

Now, with the likely cause of SARS known, some countries are trying to develop vaccines or more specific antiviral drugs. Experts have warned, however, that this could take years. In addition, viruses are prone to mutating which makes it difficult to make an effective lifelong vaccine. However, the company AVI BioPharma, based in Oregon, USA, are hoping to have a treatment for SARS in months rather than years. They have used antisense therapy, where the RNA (the precursor of DNA) of the coronavirus is neutralised with a mirror piece of RNA. This prevents more copies of the virus being produced, and halts its spread.

In China, there have been a number of alternative therapies for SARS reported.

Spread of the disease

Direct contact with someone suffering from SARS appears to be required for spread of the disease. This is seen by the fact that mainly healthcare workers or close family and friends of patients are infected. WHO believe that prolonged contact is necessary for infection to occur, and added that SARS is spread by direct contact or by large exhaled droplets of body fluids. WHO have ruled out spread by smaller aerosol droplets, as this would have lead to a much higher number of cases. The coronavirus can survive for several hours on items such as door handles, and, as SARS is thought to spread like colds and 'flu, experts have recommended frequent hand washing.

Impact of SARS

SARS has now affected nearly thirty countries worldwide.

This information was taken from the WHO website on the dates indicated, and relies on information issued by the individual countries.
Increases since previous record are indicated in red.
Note: Some countries have not submitted recent reports on their SARS cases to WHO, so figures may differ from those in the latest newspaper articles.

The effects of SARS are far-reaching and diverse.

• The American Association for Cancer Research (AACR) cancelled its meeting in Toronto earlier in April at a potential loss of US$ 7 million.
• Independent schools in the UK were recommended to monitor any children who had returned to school from an infected area, and some private schools quarantined students if they had visited an affected area.
• Medical schools in Toronto reduced access to hospital buildings to prevent spread of the disease.
• China cancelled the weeklong May Day holiday to stop people travelling, and public schools in Beijing closed for two weeks.
• Air China and Singapore Airlines are suffering from reduced numbers of travellers and Cathay Pacific Airways warned that their entire passenger fleet could be grounded.
• In the worst affected areas, tourism has suffered. In some cities, shops, restaurants and hotels are empty.
• Travel insurers have refused to offer insurance cover for SARS to those travelling around Canada, Hong Kong and China.
• On 21 April, WHO claimed that the SARS outbreak could cost the global economy up to £19 billion.
• Thousands of people in Toronto, Singapore, Hong Kong and China have been quarantined for 10 days to prevent further spread.

WHO plans to hold a Global Scientific Meeting on SARS in Geneva, 17-18 June 2003.

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For further information

World Health Organization

Contains the latest information on SARS symptoms, affected countries and travel advice.

UK Department of Health

Contains the latest UK travel information, as well as answers to FAQ's.

UK Health Protection Agency

Has information on SARS for healthcare professionals as well as for the public.

ProMED-mail

Global reporting system monitoring emerging diseases - includes current reports about the spread of SARS.

New England Journal of Medicine

This prestigious science journal has posted free reports on SARS.

New Scientist

This site has a large number of science articles on SARS, including background information and the latest news.

BBC SARS FAQs

FAQs and links to many other news articles on SARS.

Channel 4 SARS

A good source of general SARS information as well as links to other interesting SARS sites.

Greensill (University of Liverpool) and colleagues paper in Emerging Infectious Diseases.

This paper describes the exacerbating effects of co-infection with human metapneumovirus in children with severe respiratory syncytial virus infections.

Peiris (University of Hong Kong) and colleagues paper in The Lancet.

This paper describes experiments done to identify coronavirus as a possible cause of SARS.

Viral Scares, by Stuart Derbyshire, Assistant Professor at University of Pittsburgh

An interesting opinion on the initial worldwide reaction to SARS.

Pandemic of precaution, also by Stuart Derbyshire

A further opinion from Stuart Derbyshire on the reaction to SARS.

'It could be China's Chernobyl', from the Guardian.

A compilation of opinions from newspapers around the world.

'If a SARS epidemic strikes here, our best defence will be prayer', from the Daily Telegraph.

An opinion from practising GP, Theodore Dalrymple, on how Britain's hospitals would not cope with a SARS epidemic.

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Last updated 08 October 2004