Posted on 04/13/2003 6:36:02 PM PDT by Lessismore
Airborne, mutating and deadly, the Sars virus is spreading panic across the world. As quarantine camps are set up here, Health Editor Sarah-Kate Templeton reports on how it can be stopped
The mystery illness which has so far claimed 120 lives and infected more than 3100 people in 21 countries around the globe was last week formally identified as a new form of the same virus that causes the common cold. It was described in a medical journal as a 'novel coronavirus', but is to be named the Urbani virus, after a World Health Organisation (WHO) expert who died investigating the epidemic. As the panic to contain a disease that nobody knew existed a month ago spreads to the UK, where quarantine camps have been set up for pupils from southeast Asia returning to British boarding schools after their Easter break, experts admit there is little we can do to stop new viruses emerging.
The source of severe acute respiratory virus (Sars) has yet to be discovered, but scientists suspect it came from animals in the Guangdong Province in the south of China.
The report of the investigation into the virus by 12 international laboratories, published last week in the New England Journal Of Medicine, says: 'Presumably, this virus originated in animals and mutated or recombined in a fashion that permitted it to infect, cause disease and pass from person to person.
'The three known groups of coronavirus are associated with a variety of diseases in humans and domestic animals. Although the known human coronaviruses are associated with mild disease (the common cold), the ability of coronavirus to cause severe disease in animals raises the possibility that coronavirus could also cause more severe disease in humans. It appears that Sars-related coronavirus may be the first example of a coronavirus that causes severe disease in humans.'
This ability of a virus to mutate and jump from animals to humans is its great 'beauty', according to Glasgow University virologist Dr David Evans. We can do little to stop the new viruses emerging but much to prevent their spread.
'Viruses have a unique beauty and they will continue to do this,' he says. 'There is nothing we can do to stop them. We cannot stop evolution but we can have well-enough trained healt care workers who know how to recognise them and treat them. Viruses will always try to find new types of cells to grow in and they will be as happy if they are in humans as pigs. What we must be able to do is control these outbreaks.'
Recent medical history features a list of zoonoses -- diseases passed from animals to humans. They include the most deadly illnesses known to humans -- Aids, ebola virus and the bubonic plague.
Experts say areas of dense population in southern China, where humans and animals are packed side by side, provide ideal conditions for a new virus to emerge.
Dr David Brighty, a virologist at Dundee University, says: 'Many, if not all emerging viruses, have natural animal reservoirs and these viruses may be transferred to humans through exposure to infected animals. West Nile virus has a bird reservoir with an insect carrier and avian flu came from poultry. This is particularly problematic in communities that traditionally live in close contact with livestock, for example in China and Malaysia and the developing world, or alternatively where increased urbanisation brings people in contact with infected animals.
'The developing nations, including China and Indochina, tend to have environmental and social conditions that are favourable to the emergence of new viral strains.
'Change of social practices, improved sanitation and reducing animal reservoirs will all help to reduce the incidence of novel infections. However, the emergence of novel viral strains is a natural process and it is unlikely that we can completely remove the threat. Policy-makers should be concerned.'
The genetic molecule at the core of the Sars virus is an RNA (ribonucleic acid) rather than DNA (deoxyribonucleic acid). This makes the virus more unstable and prone to mutation. RNA is similar to a single strand of DNA -- two strands of DNA typically make up a cell's chromosome -- but with a small chemical difference in the structure of the chemical units called nucleotides.
Dr Marie Ogilvie, a clinical virologist at Edinburgh University, explains: 'There are several ways in which a new virus can emerge in the human population. Those viruses with RNA genes are particularly prone to small changes being allowed through as they are replicated. DNA viruses are much more stable.
'Influenza viruses are good examples of RNA viruses, where we see gradual change over the years. The influenza A virus also has the capability to acquire one or two whole new genes if it recombines with another influenza A virus and that may be a poultry or pig flu virus. In the past, that has led to pandemic spread of a new flu virus that has not been circulating in humans before; the last time was in 1968. The new coronavirus associated with Sars is also an RNA virus, and may have developed mutations allowing it to infect and spread in humans.'
But while scientists agree we cannot stop new viruses emerging, they say the havoc they cause can be limited by containing the outbreak at the earliest stage. Last week David Heymann, of WHO, told a US Senate committee that the epidemic could have been controlled if China had asked for help in November when Sars first surfaced in the southern province of Guangdong. China did not alert the World Health Organisation to the outbreak until March.
And in a highly unusual and risky move last week, a Chinese doctor and Communist Party member, Jiang Yanyong, broke ranks and accused his government of covering up the number of people killed or infected by Sars in Beijing.
Dr Jiang also alleged that hospital officials had been forbidden by the ministry of health from talking about early cases of Sars 'in order to ensure [the government's] stability'.
But experts are diplomatic in their criticism of China. Scientists from WHO and the US Centres for Disease Control (CDC) have now been admitted into the region and they hope lessons have been learned.
Dr Ogilvie says: 'Those areas seeing imported cases of Sars more recently -- US and Europe -- had the benefit of advance warning and have mostly been able to implement isolation procedures, strict infection control and surveillance of contacts so they have not had the same hospital and community transmission as happened in Hong Kong where they had no warning. The delay in the reporting to WHO of the first outbreak that occurred in Guangdong Province, south China, late in 2002, contributed to the problem.
'Hopefully the consequences of attempting to rely solely on local efforts to deal with an emerging infection of this nature have now been fully appreciated and in future any country experiencing such a problem will turn promptly to WHO and related experts for early assistance.'
Dr Evans adds: 'There are places around the world that have fantastic experience in handling these outbreaks. CDC in Atlanta has a group that is used to handling outbreaks. They have emergency teams with their bags packed, ready to go to suspected outbreaks. If the virus is not known, they can try to find out something about it. They can put in place the best type of health care and try to contain the outbreak.
'My view is that China has a responsibility to alert the authorities. It may be reticent for whatever reason. CDC and WHO have teams there now, but Sars is already all round the world.'
And the rest of the world is now taking unprecedented precautions to contain the virus. US President George Bush took the unusual step of giving federal health officials the power to quarantine Americans suspected of suffering from Sars. In an executive order, Bush added Sars to the list of diseases over which authorities have this power, the first time an addition has been made in the past 20 years.
In Singapore, surveillance cameras have been installed in the homes of people placed under quarantine after 12 flouted the orders. The Singapore health ministry has ordered those who are quarantined to report in front of the camera several times a day. If Sars victims are not at home when health-care workers check, they will then be forced to wear an electronic tag on their wrist. The tags are linked to a telephone line and alert the authorities if the quarantined leave their homes or try to break the tag.
In Canada, criminal action may be taken against a Hewlett-Packard employee who infected a co-worker with Sars and forced almost 200 employees to go into quarantine. The medical officer of York Region, Ontario, says the man misled public health authorities into believing he was at home under quarantine when, in fact, he was going to work.
And in the UK, where there are now six probable cases of Sars, two quarantine camps have been set up for children returning to British boarding schools from infected areas in southeast Asia after the Easter break.
The camps have been set up by a guardianship agency -- a company which organises British families to act as guardians for foreign pupils in the UK. Many British boarding schools are refusing to accept pupils returning from Singapore and Hong Kong until they have spent 10 days in quarantine in this country. As families appointed as guardians are uneasy about accepting the pupils into their homes, White House Guardianship, acting on behalf of the trade body, the Association of Guardianship Services, has taken over two holiday camps on the south coast of England where 200 children will be held.
But the fears are justified, according to WHO which has described Sars as 'the first severe new disease of the 21st century with global epidemic potential'.
A WHO statement says: 'Although the last decades of the previous century witnessed the emergence of several new diseases, Sars needs to be regarded as a particularly serious threat for several reasons. Its clinical and epidemiological features, though poorly understood, give cause for particular alarm. With the notable exception of Aids, most new diseases that emerged during the last two decades of the previous century or established endemicity in new geographical areas have features that limit their capacity to pose a major threat to international public health.'
Some new diseases such as avian flu failed to spread efficiently between humans. E coli 0157 and vCJD depend on food for transmission. And although outbreaks of ebola haemorrhagic fever have had high fatality rates, person-to-person transmission requires close physical exposure to infected blood and other bodily fluids. And patients suffering from this disease are visibly very ill and too unwell to travel.
It is the familiar, everyday guise of the mutated form of the common cold, WHO says, that makes Sars so dangerous.
'Sars is emerging in ways that suggest great potential for rapid international spread under the favourable conditions created by a highly mobile, closely interconnected world,' adds WHO. 'The initial symptoms are non-specific and common. Anecdotal data indicates an incubation period of two to 10 days, allowing the infectious agent to be transported, unsuspected and undetected, in a symptomless air traveller from one city in the world to any other city having an international airport.'
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| Our troops give so much of themselves, and we all benefit from their efforts. The next time you look at your bank balance, why not find some way to take some money and put it towards supporting the members of our armed services in some way? Maybe find a family who has someone serving, and buy them dinner, or some groceries, or a gift for their children? Maybe find a way to contribute to a fund for the memory of any of those who have fallen? Our armed forces deserve our support in tangible ways.
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Good idea. Last thing we need is a nation-wide paranoia over being out in public places like we see in China.
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