Anatomy of the deadly China syndrome

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Artykuł pochodzi z pisma "Guardian"

Anatomy of the deadly China syndrome

Sars is first of many epidemics to come

Ian Sample, science correspondent
Friday April 25, 2003
The Guardian

We're unsure where it came from, have no treatment for it and no idea when or where it will spread next. The virus that causes severe acute respiratory syndrome is shrouded in unknowns. But two things are agreed upon: it's lethal, and it's not going to go away. What's more, we can look forward to far more new and extremely dangerous viruses in the next few years.
In mid-February, a retired Chinese doctor, Liu Jianlun, began suffering flu-like symptoms. In the same week he travelled to Hong Kong for a wedding and checked into the Metropole hotel. After developing a temperature, he went to hospital and asked to be put into isolation.
It was too little, too late. Soon hospital workers began falling ill. Fellow guests at the Metropole were also taken sick but not all of them went to hospital; instead, they simply checked out and took Sars with them - to Canada, Singapore, and beyond.
On March 4 Mr Liu, "patient zero", died.
Meanwhile, in late February, Dr Carlo Urbani, the World Health Organisation's epidemiologist in Vietnam, identified the first case of Sars in Hanoi and reported back to WHO headquarters. Urbani was himself killed by the virus on March 29.
The world began slowly waking up to the fact that it had an outbreak on its hands - the outbreak of a virus to which no human had any immunity, and which killed up to one in 10 of its victims.
The WHO warned disease control centres around the world; doctors began taking blood samples and throat swabs from patients arriving in their surgeries with flu-like symptoms. These samples were sent on to a host of monitoring labs, including the US centres for disease control and prevention in Atlanta and the health protection agency in Colindale, north-west London, and scientists set about identifying the virus and developing a way to test for it.
In these two things they were successful. The virus has been identified: it is called a coronavirus because of its characteristic crown shape under a microscope. And there is now a test for it. But treatment is another matter. So far our best and only defence against Sars is containment.
"We haven't got anything effective to throw at it," says Professor Peter Openshaw, an expert on respiratory diseases at Imperial College, London. Patients have been treated with a variety of antiviral drugs, antibiotics (for secondary bacterial infections) and steroids.
While steroids can help calm inflammation of the lungs - which is what actually kills you if you develop Sars - the other drugs have yet to prove their efficacy. Meanwhile, the virus has now infected more than 4,000 people in five continents. It has killed more than 250.
Containment will not wipe out Sars, however. The reality, when dealing with outbreaks, is that you can never achieve 100% containment. "It won't stop growing," says Ian Jones, a virologist at the University of Reading. "The whole purpose of a virus is to create copies of itself. It's not going to give up doing that. It may now be with us for ever more."
Most viruses which attack humans come from animals - often cats, dogs or cattle. The virus that causes Sars probably came from pigs and birds, which would typically suffer diarrhoea and pneumonia.
How it strayed from pigs or birds to humans is as yet unproven, but the best scientific guess is that a chance mutation in the virus gave it the ability to jump the species barrier. In many regions, this would have been a minor problem - it may have led to nothing.

Vaccine

But in the southern Chinese province of Guangdong, it was to prove a major problem. As in other regions of China, animals and birds are kept in close proximity to dense populations of people in the region. These were the perfect conditions for the virus to spread away from its traditional hosts into humans.
The virus probably spread and festered in China unnoticed for some time, not least because of a general reluctance among locals to visit hospital. "People typically resort to traditional Chinese medicine first and might only go to hospital as a last resort when they are very ill," says Professor Roy Anderson, an epidemiologist who is working with the Chinese authorities to assess how the epidemic will develop.
"We're trying to work out how infectious it is, the incubation period, the route of transmission. The bad news is the epidemic is self-sustaining, at least in Hong Kong. The epidemic is still building."
This is a virus that in theory could kill millions of us: it may spread more slowly, but it is more lethal than the Spanish flu which killed up to 50 million people after the first world war.
All this means that developing a treatment is a high priority. The best route is to develop a vaccine.
However, a usable vaccine will not be ready soon."If you solved every possible pitfall along the way as soon as you hit it, you might have something ready in five years. But realistically, it's going to be 12," says Prof Openshaw.
Vaccines are typically expensive, so even when one is developed, it will probably be beyond the budgets of poorer nations. But these are the very countries the WHO fears could be devastated by Sars if it gets a foothold. "If it gets into Africa, we might never dig it out," says the WHO's Dick Thompson.
If it hits a population already ravaged by HIV, the number of deaths from Sars could rocket, Professor Luc Montagnier, one of the scientists who discovered the HIV virus, warned this week.
Although Sars is unprecedented, increased air travel and the closer proximity of man to animals means we will see a lot more new viruses emerge in the future. "Rather than becoming rarer, these events are likely to become more frequent," says Prof Anderson.
There are lessons to be learnt from Sars, he adds. Sars shows that the western world has to take responsibility for health in other countries.
"It's not sufficient for the rich countries to have sophisticated health care," he says. "We've got to help other countries have equally sophisticated mechanisms."
It could get even more serious. Health officials are now on the lookout for two distinct signs that mean the epidemic could worsen. The first are called asymptomatic spreaders - people who carry the virus without developing symptoms. Left to mingle with the masses, asymptomatic spreaders could cause a serious hike in the number of people falling victim to Sars.
The second sign officials fear are so-called tertiary infections - people infected with Sars who cannot be traced to someone known to have been directly exposed to the virus.
If the trail fails to find who spread the infection, it is bad news: the virus is at large.

Acute – severe
In containment – kept isolated
Efficacy - efectiveness
To fester - ropieć
Foothold – punkt zaczepienia
Hike - wzrost
Lethal - śmiertelny
To mingle – to mix with
Pitfall – a difficulty, an obstacle
To ravage – cause damage
Reluctance - niechęć, opór
To resort to – uciekać się do
To shroud -hide
To stray – uciekac, błakać się
Sophisticated - wyszukany
Swab - tampon, wacik


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