SARS - Waiting For The Cure

[Dave Farber <dave () farber net>]

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From: Trish.Saywell.-.Far.Eastern.Economic.Review () central cis upenn edu
Reply-To: Sg_Review () yahoogroups com
Date: Thu, 27 Mar 2003 00:30:00 -0000
To: Sg_Review () yahoogroups com
Subject: [Sg_Review] SARS - Waiting For The Cure

HEALTH

Waiting For The Cure

Some scientists believe they may know the cause of the illness that
has spread across the globe, but uncertainty prevails. Here's what is
known so far and what to look for as the outbreak proceeds on its
unpredictable course


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By Trish Saywell/SINGAPORE with David Lague/PERTH and Susan V.
Lawrence/BEIJING

Issue cover-dated March 27, 2003


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THE MYSTERIOUS and deadly disease that appears to have spread from
China to the world, killing at least 10 people and infecting hundreds
on three continents, could be a virus. Or maybe it's a bacterium.

  WHAT TO LOOK FOR 
 
-- High fever (over 38 degrees Celsius)
-- AND one or more signs of symptoms of respiratory illness
including: coughing shortness of breath, difficulty in breathing,
hypoxia, radiographic findings of pneumonia, or respiratory distress

-- AND one or more of the following:
- history of travel to Hong Kong, or Guangdong province in southern
China, or Hanoi, Vietnam, within seven days of symptom onset
- close contact with a person with respiratory illness having the
above travel history. Close contact includes having cared for, having
lived with, or having had direct contact with respiratory secretions
and body fluids of a person with Severe Acute Respiratory Syndrome

SOURCE: Centres for Disease Control and Prevention
 

It could be transmitted through droplets. Or maybe through body
fluids, or possibly as an aerosol. In fact, the only thing doctors
really know about this illness, which the World Health Organization
is calling Severe Acute Respiratory Syndrome (SARS), is that they
don't know exactly what it is.

This uncertainty is worrying the policymakers who are advising on how
to prevent its spread, the scientists who are trying to determine its
cause, the doctors who must treat it and the anxious health-care
workers and residents of southern China, Hong Kong, Hanoi, Singapore
and other hot spots around the world who hope to avoid it. Even the
best-case scenario for the new mystery disease is likely to take time
to play out. 

As the Review went to press, researchers in Hong Kong and Germany
said they had isolated an agent, apparently belonging to a class of
viruses associated with measles and diseases in birds and animals,
that they believed could be responsible for SARS.

But the WHO says it's too early to say whether that virus,
paramyxovirus, is the culprit. "This is a preliminary finding from
one patient only," the WHO said in a statement. "It has to be
confirmed with other cases in other laboratories. Still, we see it as
the first lead to a possible cause."

And determining conclusively if this is the agent is crucial to
enabling officials and researchers to judge how far and how fast the
illness could spread. "Is it going to get a lot worse or is it going
to remain under control? No one can predict," says David Bell, a WHO
public-health physician in Manila.

The WHO said on March 18 that 219 hospitalized cases have appeared
worldwide in recent weeks. In addition, China last month reported 305
cases of atypical pneumonia in its southern province of Guangdong.
The WHO noted that the China cases haven't been conclusively linked
to the others, but exhibit striking similarities in their symptoms.

Evidence gathered so far indicates that to contract the illness
people must come into close and prolonged contact with infected
people. "The vast majority of cases have had very close or prolonged
contact with another case and a large proportion of cases have been
among health workers," says Bell. "Normally in a flu epidemic most
cases are infected in the general population, so this [disease] is
fairly limited compared to what you'd see in a flu epidemic."

Officials have found no definite evidence that any one drug is
effective against the illness. "As a baseline, it is critical to know
if the agent is a virus, bacterium or something else," says Kennedy
Shortridge, a leading influenza researcher and emeritus professor at
the University of Hong Kong.

"People are trying different things including broad-spectrum
antibiotics and anti-virals," says Bell. "You may find an effective
treatment without knowing the specific organism causing the disease."
China is reporting that for its cases, antibiotics did not have an
obvious effect. 

If it is a virus, as the latest research suggests, it could be the
tougher challenge. "There are drugs that will help suppress virus
infection of cells," says Tom August, director of research at Johns
Hopkins Singapore. "But there's not a single instance, despite all
these years of research, of a drug that can cure a virus infection.
An added complication is that viruses replicate quickly and mutate
very rapidly and thus can evade drug therapy."

In late February, at China's invitation, a WHO team travelled to
Beijing to try to help determine if the Guangdong cases were caused
by the H5N1 bird-flu virus. Their conclusion was that based on
available data it was "unlikely" that they were related to the avian
flu, Alan Schnur of the WHO said in Beijing on March 17. He said the
WHO would be helping Chinese laboratories launch more sensitive
testing in Guangdong and in Fujian province "to exclude any chance
that these cases are due to the H5N1 or some new virus."

Some researchers believe that most influenza pandemics in recorded
history originated in bird populations in southern China and that
Hong Kong will be close to the epicentre of the next pandemic of a
new contagion similar to those that swept the globe three times last
century. 

This is due in part to China's large population and the fact that
many communities practise both pig and duck farming. Given the wide
climatic variation from northern to southern China, influenza
infections of humans occur year round somewhere in the country.

Graeme Laver, a retired professor of virology at the Australian
National University and a pioneer of research into the origin of flu
epidemics in southern China, says the origin of the disease "could be
a big surprise. It could be a totally unknown organism, another type
of influenza or even a B-strain."

Laver adds that the crisis gives a hint of what would happen if a
lethal flu virus got going. "There is already a certain amount of
fear and uncertainty," he says. "This is a dress rehearsal for a real
pandemic. If it was a lethal flu, there would probably be hundreds of
thousands of people dead by now."

If it turns out that the disease is a variant of influenza, currently
available flu vaccines might help to provide some measure of cross-
protection if the bug has some antigens in common with currently
circulating flu strains, some experts say. "Even mild cross-
protection might make the difference between life and death," notes
Gurinder Shahi, a medical doctor in Singapore with a specialty in
public health and who is CEO of BioEnterprise Asia, a health-care and
biotech consultancy. He suggests that anti-flu drugs like Relenza and
Tamiflu could be useful in helping to fight the disease and provide a
first line of defence while authorities work on a vaccine.

Of course, the organism causing SARS could still turn out to be a new
strain of bacteria. In 1976, it took six months to identify the
bacterium that caused Legionnaire's Disease. And if it is a new
bacterium, it may even have developed some resistance to antibiotics.

"Twenty years ago the medical world thought they had bacteria licked
and there were drugs for every occasion," says Philip Masters, a
Singapore-based lab director at Covance, a clinical research
organization. "Now that's not the case. As soon as an agent has been
found to kill them, they'll find a way of overcoming its activity."
  




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