Severe Acute Respiratory Syndrome (SARS) Faye Jones

In mid-March 2003 A brief history known human corona- the World Health Outbreak. The SARS outbreak is thought to have viruses, 229E and OC43. Organization (WHO) originated in the Guangdong province of southern China These caused between 5 issued emergency in mid-November, last year. Over 300 people were taken and 30 % of common colds guidance for travellers ill with a new infectious disease and 5 people died. In and could also cause and airlines in the light February this year, a doctor fell ill whilst attending a intestinal . of ‘a worldwide health wedding in Hong Kong. He had been treating the threat’ from a new patients in Guangdong. It is believed that he infected Genome of SARS agent infectious disease several guests who were staying in the same Hong Kong revealed. By April, called Severe Acute hotel, as well as medical staff, after being admitted to scientists in Canada and Respiratory Syndrome hospital. He later died of the . the US had both sequenced the genome of the virus (SARS). This infection, most linked with SARS. Their results confirmed the which was mainly Out of Hong Kong. The disease then spread outside cause as a , different from all those previously affecting people in the Hong Kong with the infected hotel guests. These known. The cause of SARS has now been documented Far East, started with included Singaporeans, Canadians and a Chinese- by the WHO as SARS coronavirus (SARS CoV). ‘flu like symptoms American businessman. The businessman travelled from and rapidly turned to Hong Kong to , , and fell ill a few days Coronavirus. are enveloped, single- pneumonia. Thought later, infecting hospital workers there. The World stranded RNA viruses. They have a genome of to be caused by a virus, Health Organization (WHO) asked Carlo Urbani, an approximately 30 kilobases, the largest of the RNA SARS defied treatment infectious disease specialist, to advise in Vietnam. He viruses. This family of viruses is named for their crown- and was proving fatal in realized the disease was something new and called it like appearance, which is due to an array of surface many cases. Since this Severe Acute Respiratory Syndrome (SARS). Due to his projections on the viral envelope. Typically, they have a announcement the close work with SARS patients, Carlo Urbani himself narrow host range and they replicate in the cytoplasm disease has spread to became infected and died in March. of the host epithelial cells. many other countries, fuelling much media Teamwork required. The WHO began to co-ordinate Symptoms hysteria and general a number of international laboratories to work together SARS is an atypical pneumonia, with symptoms that panic. As we go to to find the cause of the disease. Microarray analysis on are ‘flu-like. These include high (greater than press, the WHO has samples indicated that a coronavirus was the cause of 38 °C), aching muscles, chills, sore throat, headache, announced that the the disease. In particular, they observed a strong link dry cough, shortness of breath, breathing difficulties, worst is over. Faye between the SARS virus and two other coronaviruses: and in a number of cases, diarrhoea. Research published Jones, SGM Public avian infectious bronchitis virus and a bovine in The Lancet suggested that SARS CoV kills 1 in 5 Affairs Administrator, coronavirus. At this time, there were already two people infected. Those aged over 60 are most at risk, with has chronicled the whole over half those infected dying; the death rate is about 7 % story week by week in those aged under 60. The incubation period is 2–10 on the SGM website days, and the infectious period does not start until the (www.sgm.ac. uk/ onset of symptoms. Antibodies to SARS have been news/hot_topics/ detected in patients from about 10 days after the start sars.cfm). Here is her of clinical symptoms. summary of what has been dubbed ‘the first Diagnosis global epidemic of Early on in suspected cases, the presence of the SARS the 21st century’. CoV polymerase gene is detected using the polymerase chain reaction (PCR). Much later on in infection, the immune system produces antibodies to the virus, which allows serological methods of detection to be employed.

Treatment There is currently no cure for SARS. Some patients have been treated with a non-specific antiviral drug, ribavirin. 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

PHOTO DIGITALVISION antibodies taken from recovered patients.

124 MICROBIOLOGYTODAY VOL 30/AUG03 Lessons LEFT: During this outbreak of SARS, over 30 countries world- Electron micrograph of the SARS virus, negatively stained wide have reported probable cases of infections. Tens of with phosphotungstic acid, at thousands of people have been either directly or an approximate magnification indirectly affected by the disease, from contracting the of × 320,000. illness itself to public holiday cancellations, school COURTESY HAZEL APPLETON, closures, and, in the worst affected areas, 10-day HEALTH PROTECTION AGENCY voluntary for many thousands of residents. Since March, the WHO has continued to issue travel bans on the worst affected areas, lifting them when it Spread of the disease was considered safe. This has had an economic impact Direct contact with someone suffering from SARS on many industries, particularly travel and tourism. appears to be required for spread of the disease. This is After it was revealed that China had initially under- seen by the fact that mainly healthcare workers or close reported cases of SARS, the disease spread out of control family and friends of patients are infected. The WHO there. In Canada, it was announced that SARS was under has stated that SARS is spread by prolonged direct control and no longer spreading. No new cases had been contact or by large exhaled droplets of body fluids. The reported there for over 4 weeks, that was, however, until organization has ruled out spread by smaller aerosol it resurfaced in May with at least 20 new cases. Alan droplets, as this would have led to a much higher number Milburn, the UK Health Secretary, has said that he wants of cases. SARS CoV has been shown to survive for up to international law to be strong enough to ensure that 48 hours on plastic surfaces and up to 4 days in diarrhoea. demands by the WHO in relation to such outbreaks are It is thought to spread like colds and ‘flu, and as such, carried out by all countries. experts have recommended frequent hand washing. The The figures (from the WHO) for 20 June 2003 put virus loses its ability to infect after exposure to a number the number of probable cases of SARS at 8,461, with the of commonly used disinfectants. number of deaths at 804.

SARS source Further information The source of the SARS virus was a mystery for quite a while. Early on in the outbreak it was believed that the WHO virus may have come from pigs or chickens and mutated http://www.who.int/csr/sars/en/ to infect humans. However, attempts to infect these Contains the latest information on SARS symptoms, animals with the SARS virus failed. Then, despite affected countries and travel advice. there being no scientific evidence for it, fears grew in China that pets were the hosts for SARS, leading to UK Department of Health extermination patrols killing hundreds of cats and http://www.doh.gov.uk/sars/index.htm dogs. Contains the latest UK travel information, as well as Finally, the source of SARS CoV was revealed to be answers to FAQs. the masked palm civet. This cat-like mammal is related to the mongoose, and is regarded as a delicacy in UK Health Protection Agency Guangdong province where the outbreak first http://www.phls.org.uk/topics_az/SARS/menu.htm originated. Microbiologists at the University of Hong Has information on SARS for healthcare professionals as Kong checked large numbers of domestic and game well as for the public. animals to try to find the cause of SARS. It is believed that the virus jumped to humans as they raised, Faye Jones, SGM Public Affairs Administrator slaughtered and cooked the animals, rather than from eating infected meat. Virus samples very similar to coronavirus were isolated from the faeces and respiratory A fuller bibliography on SARS and the whole detailed story fluids of four individual civets. This information should of the outbreak is available on the SGM website Newsdesk help prevent further outbreaks through controlling (www.sgm.ac.uk). For a virologist’s opinion on SARS, see the sale and slaughter of these animals in China. Comment on p. 152.

Vaccine development Studies in The Lancet show that the SARS virus is not mutating as expected. This news is likely to make the design of a vaccine to prevent further outbreaks much easier.

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