Posted on 05/02/2003 8:39:46 AM PDT by CathyRyan
An excessive immune reaction appears to be the fatal factor in patients who die of SARS, according to medical data from Hong Kong. The best estimate of the fatality rate of SARS is rising steadily and so understanding how the disease causes death is critical to finding the best treatments.
Scientists have also discovered that the SARS virus can remain viable for at least 24 hours after being deposited in a droplet on a plastic surface - a simulation, for example, of an infected person coughing on to the wall of a lift.
The new information was revealed by Klaus Stöhr, the World Health Organization's chief scientist for SARS in a briefing earlier this week. "In the first week or so of disease the virus is replicating mainly in the upper respiratory tract, causing high fever and dry cough. But in the second week we see an over-reaction of the immune response, and in 20 per cent of cases that leads to very severe disease."
Mark Salter, WHO's coordinator for the clinical management of SARS, told New Scientist that this excessive response seems to be destroying the alveoli, the tiny sacs at the end of the lung tubing where the oxygen is absorbed. It is like stripping all the leaves from a tree, he says, making breathing extremely difficult.
"The immune response develops, but then continues growing unchecked" says Salter. "You then get cytokines, tumour necrosis factor and so on released not just at the virally infected cells they are supposed to kill, but throughout the tissue". This also happens in other diseases but the mechanism is not entirely understood, and certainly not in the case of SARS, he says.
Flare up
Nevertheless the observation significantly strengthens the basis on which doctors can select the treatments given to patients. In particular, it suggests the use of corticosteroids, alongside other drugs that reduce the viral load such as interferon.
Corticosteroids suppress the immune system and are normally used against asthma, rheumatoid arthritis and in transplant patients to reduce the risk of rejection.
Their use does raise the risk of further infection, but Hong Kong hospitals are claiming success with combinations of the antiviral ribavirin and pulsed steroids, says Salter: "And once steroids are stopped, they see a flare up of the condition suggesting there is a significant immune component to the disease."
. The issue of how long the virus survives outside the body was also raised by Stöhr. Some scientists have argued that long survival could explain unusual cases of transmission in Hong Kong and Canada.
In a study in Germany reported by Stöhr, the virus was dropped in liquid on to a plastic surface, the drop was dried, and examined after 24 hours. "There were 10,000 virus units per millitre before, and after 24 hours there were 1000 - and that was viable viruses."
A 'contagion' that is only visible using an electron microscope and you're hypothesizing that some back-woods labs in China 'cooked' this contagion up?
SINCE you brought it up - one must assume that you have some knowledge on how this might be done -
- care to share this with us?
It wasn't until 1935 that a virus was actually identified and by 1939 a virus could be seen for the first time using the newly developed electron microscope.From: http://www.scienceandyou.org/articles/edit_05.shtml
LOL!
YOU brought it up -da nile that is- and with SARS on the decline EVERYWHERE except in China ...
A couple of WEEKS ago there were rumors abounding about how TERRIBLE a world-wide contagion this would be. Now, it's only in China ...
Good work by our medical profession - don't you think?
Yes I do. Shows what good old fashioned isolation and containment can do.
So when are you going to answer the questions I asked?
That's the pessimist's viewpoint alright, a classic 'The glass is still half empty' complaint ...
Nowhere, not even in China, can you point to 'exponential growth' in the number of cases. Were THAT to be seen I would change my tune immediately.
As anyone who has ever been in love knows, as time passes the desire to change the beloved becomes irresistable. In the old days virologists changed their viruses like Mendel altered his peas, selecting and breeding for characteristics that were useful and interesting. It was a long and messy process. Molecular biology revoltinized this in the 1970's. Suddenly, a virus was less like a hardbound book and more like a three ring binder: The power to cut and paste genes aenabled virologiststo remove pages og genetic information and replace thwem with others. The implications for vaccine research were tremendous.
excerpted from Big Shot by Patricia Thomas
MY overall view of this situation is on a different plane than yours - therefore the questions you pose based are based 'from that plane' either a) do not have the relevancy (as I see it) or b) are posed in such a nature that prohibits an acceptable answer *outside* 'that other plane'.
I also think that you don't consider a variety of other factors, factors such as the necessary control of the civilian population to prevent en masse exodus from, say Beijing, into the other parts of the country. It *is* requisite that some controls be exercised on the people - be it outright quarantine *OR* voluntary restriction to their own neighborhoods, towns, villages and even, in the case of student populations - their dormitories. This 'voluntary' cooperation can be elicited in a variety of ways, including the use of the press (media) in their country ... to wit, some of the 'hopeful' messages referring to vaccines that may be available in the near future for SARS, and this is not an idle 'hope' as opposed to the spread of ill-informed gossip that must be prevalent on the streets of China right about now ...
Kind af a 'secret too big to keep' don't you think?
I'm still reading what gets posted on FR about it but I'm beginning to think it's not going to be that much of a disease when all the facts come out. It seems to me to be a fairly serious cold or flu and mostly hospital associated ----like many are. Lots of patients get sick in hospitals from the other patients ---and so do the employees.
I found it troubling that it survives for such a long period of time outside a host. If I were going to play around with bugs, that may be one characteristic I would factor in.
As aristeides, politely pointed out there are corona viruses that live outside for longer periods.
I guess I don't understand your cantankerous attitude. If you feel you are on such a higher plane, surely there a purely scientific boards where you can go and be among others that can stimulate your mind. Us morons, here on Free Republic, must bore an intellectual giant such as yourself.
HAVE you at all paid attention to some of the Avian Flu virues that has 'shown up' in Europe? WHY don't you have the same sort of 'tin foil take' as to their origins?
Is it *just* possible that nature develops some of all of these contagion by herself without *any* help from man?
Absolutely.
There are even recorded cases of Legionnaires Disease caused by hot water distribution systems in hospitals ...
YOU overlook my point - you DON'T build these facilities out of 'vapor' - it takes PEOPLE and BUILDINGS and LAB EQUIPMENT and INFRASTRUCTURE (electric utilites to the building, roads for the lab workers and water and sewage service) -
- SOMEWHERE (if the 'tin foil' theories are correct) THESE facilities exist and the *people* in the area *know* about it. Think about the buildings, the factories in YOUR area - for the most part you *know* what these places produce - how much more so do you think the intelligence agencies *know* these things (THEY can track shipment of critical 'gear' from manufactures as would be USED in such labs) -
- PLUS, a LOT of this automated, sophisticated 'lab gear' requires constant maintenance (Field Service) and this service comes from the competent service personnel direct from the factory - follow the trail of personnel and you're 'one up' on what-is-where ...
(And YOU only thought your office's Xerox copier had factory service and support!)
The facility is where you put it.
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