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parallaxicality
2005-Oct-12, 08:02 PM
I'm not one for complacency concerning the next great plague, but surely the virus that caused the most devestating pandemic of the last century is a far more direct threat than a virus that has so far only killed sixty-four people worldwide, so recreating the one to understand the other seems a bit heavy-handed.

TriangleMan
2005-Oct-13, 10:59 AM
The 1918 virus actually had a "small" death rate (I think around 5% of those infected died) while the current H5N1 virus' death rate may be higher. We currently have no immunity to H5N1 while in general the population does have some level of immunity to the 1918 virus, since the people it didn't kill went on to have children and passed on whatever genetic resistance we had to the virus. It is also possible, though I haven't looked it up, that less-nasty variants of the 1918 virus have been cirulating in the population ever since, thus allowing people to build up immunity to it.

beskeptical
2005-Oct-14, 06:05 AM
The 1918 virus actually had a "small" death rate (I think around 5% of those infected died) while the current H5N1 virus' death rate may be higher. We currently have no immunity to H5N1 while in general the population does have some level of immunity to the 1918 virus, since the people it didn't kill went on to have children and passed on whatever genetic resistance we had to the virus. It is also possible, though I haven't looked it up, that less-nasty variants of the 1918 virus have been cirulating in the population ever since, thus allowing people to build up immunity to it.H5N1 has been extremely lethal to poultry with an incredibly high death rate on the order of 90%. That combined with the 30-50% fatality rate among known human cases has the experts quite concerned. Estimates for a pandemic are that the death rate could be as high as the 1918 H1N1 strain but no one expects it to be 30-50%.

You have to consider the death rate along with the case rate for it to have any meaning. Small Pox kills 30%, rabies kills almost 100%, and so on but it also matters how many people get infected. Mice were infected with the 1918 strain that was reconstructed and they turned out to shed very large numbers of virus. That likely contributed to the number of fatalities as much as the death rate.

There are some that are very unhappy not just that the 1918 virus was resurrected but that the genetic information was then made public and readily available. One can only hope other researchers will not be careless when they decide to repeat the research.

aurora
2005-Oct-14, 06:39 PM
I'm not one for complacency concerning the next great plague, but surely the virus that caused the most devestating pandemic of the last century is a far more direct threat than a virus that has so far only killed sixty-four people worldwide, so recreating the one to understand the other seems a bit heavy-handed.

I think what hasn't been stated is that the main reason that the current virus has only killed 64 people is that so far it has not mutated to be able to be transmitted directly from human to human.

If it can manage to mutate so that it can, combined with the high death rate as pointed out by others in this thread, then the overall threat is very great indeed.

And from what I have read, the virus is mutating fairly rapidly, so it is not an idle worry that it will be able to eventually move from human to human.

Ken G
2005-Oct-15, 03:11 AM
My question is, which is more likely, that a particularly nasty virus that so far does not spread from human to human will mutate to obtain that ability, or that one of the many viruses that already can spread from human to human will mutate to become particularly nasty? Does anyone know this? And if not, then why is this new threat getting so much press?
Furthermore, we already have a particularly nasty virus that does spread from human to human, under the right circumstances. It is called HIV, the scourge of many undeveloped areas. Why is the potential threat of H5N1 worth more air time than the known threat of HIV? Oh yeah, I forgot-- the news cycle.

Enzp
2005-Oct-15, 09:58 AM
The viri that already pass human to human are simiar to existing viri and our bodies are better able to cope with it. It is easier to make up vaccines for this too.

Flu viri mutate easily and readily. It is likely that the thing will eventually jump to humans, most likely through a third animal. And when it does we will have zero immunity to it. So if it comes it is likely to be very dangerous, while existing human flu viri will mutate but are not likely to instantly become so different from existing lines as to be nearly as lethal.

Researching HIV is not mutually exclusive of researching the flu. HIV is not new, and so it does not garner a lot of face time on TV or the front page. It also is not likely to wipe out a continent worth of people inside of a month once set loose. This new flu thing is news because it is something changing in our lives and our environment. I am not putting one as more important than the other, but the flu can kill large numbers in a short time and can spread in a day or two to every corner of the earth.

Another factor is political. There is a segment of society that still looks upon HIV as somehow dirty or sinful. They think that all HIV victims are promiscuous drug users. They fight efforts to send substantial aid. There is no social stigma attached to the flu. Furthermore, flu can come and take down my family, while the likelihood of my wife and I contracting HIV is vanishingly small. The flu thus threatens my family while HIV does not. Not directly anyway.

Ken G
2005-Oct-15, 01:15 PM
So if it comes it is likely to be very dangerous, while existing human flu viri will mutate but are not likely to instantly become so different from existing lines as to be nearly as lethal.


That does seem like a valid point. But where did the avian flu come from? It's new to birds obviously-- by what you're saying, it must have come from something else that was used to it and had immunity to it (or else we have to keep looking for other sources, ad infinitum). I wonder what that was, and if there is already immunity there, perhaps it would help us find a vaccine?

beskeptical
2005-Oct-15, 10:38 PM
Influenza viruses undergo random mutation all the time as do Corona viruses like SARS and all the other organisms that infect us. Some do mutate more readily, some replicate more abundantly. But a genetic change that make a virus or bacteria capable of causing a pandemic could come from many currently circulating organisms.

HIV emerged when a road was built across Uganda, literally. Truck drivers and prostitutes along the road allowed a virus that had been confined to a small geographic area to break out. From there a variety of just right circumstances allowed the disease to become a world wide pandemic. And it is indeed a major pandemic. Since it kills so slowly, the effect on the world's psyche is quite different than if it were a flu pandemic which kills within days.

The black death (plague) of the middle ages became a pandemic when rats on ships brought it to cities that were crowded and infested with rats and fleas. Tuberculosis became a pandemic when rural dwellers moved into crowded cities.

Sometimes it is the organism that changes, sometimes it is other circumstances that allow a disease to spread. Rheumatic fever from strep throat infections, rapidly invasive group A strep, meningococcal disease, and many other bacteria can go from mild or no disease to rapidly fatal by just having small genetic variations. Corona viruses can cause a mild cold or fatal SARS with very small genetic differences.

Just about any infectious organisms can mutate into a deadly version by mere chance. After that, milder versions tend to be selected for as the worst cases tend to kill the host before spreading.

The reason everyone is so worried about a pandemic of influenza is because they have occurred on a regular basis in the past. In addition, the influenza pandemics of the past have been preceded by the development of a substantially new virus in birds. It's like earthquakes, we know they will happen we just don't know when.

There are some researchers who think H5 viruses will never become highly contagious in humans. On the other hand, this particular strain is following the pattern of past pandemics. What is really happening is we know a lot about human flu pandemics but we don't know quite enough to know if this is the beginning of one or not.

beskeptical
2005-Oct-15, 10:45 PM
That does seem like a valid point. But where did the avian flu come from? It's new to birds obviously-- by what you're saying, it must have come from something else that was used to it and had immunity to it (or else we have to keep looking for other sources, ad infinitum). I wonder what that was, and if there is already immunity there, perhaps it would help us find a vaccine?Flu viruses circulate in birds just as they do in humans and many other species. Every so often chance mutation allows the virus to invade more readily, make mores copies, make a deadly enzyme or any number of other changes that cause a higher fatality rate. In the case of flu viruses, not only do they mutate, but they also reassort their genes with other flu strains leading to new combinations just like human offspring are a mix of the parents. This makes new strains particularly common with this virus family.

We have a vaccine. The problem is making enough of it fast enough. And the second problem is adjusting the vaccine in time when the virus shifts genetically to become contagious among humans. We can't predict those changes ahead of time and we can't make vaccine in less than a few months.

In 1918 the flu virus spread worldwide in 4 months without air travel. It not only takes that long to make vaccine, the vaccine manufacturers met 2 years ago in Europe and predicted if all the capacity to make vaccine was used, in 6 months they could make enough for 5% of the world's population.

beskeptical
2005-Oct-15, 10:56 PM
The viri that already pass human to human are simiar to existing viri and our bodies are better able to cope with it. It is easier to make up vaccines for this too.Not necessarily easier to make vaccine, but the current H5N1 vaccine is taking larger amounts and 2 doses to confer immunity because humans don't have preexisting immunity to similar strains.


Flu viri mutate easily and readily. It is likely that the thing will eventually jump to humans, most likely through a third animal. ...This is the current theory but the resurrection of the 1918 flu strain indicated it may have not reassorted in pigs but rather mutated directly to become infectious in humans.

Ken G
2005-Oct-16, 02:50 AM
Thanks beskeptical, it sounds like you have a great deal of knowledge about this and are good at communicating it clearly. The thing I still don't understand is, if a virus that already existed in birds but wasn't so deadly can mutate to one that is deadly for birds, then why do human pandemics have to start with birds? If a bird pandemic can appear in birds all by themselves, why would it not be easier to get human pandemics from humans all by themselves?

beskeptical
2005-Oct-16, 07:23 AM
Thanks beskeptical, it sounds like you have a great deal of knowledge about this and are good at communicating it clearly. The thing I still don't understand is, if a virus that already existed in birds but wasn't so deadly can mutate to one that is deadly for birds, then why do human pandemics have to start with birds? If a bird pandemic can appear in birds all by themselves, why would it not be easier to get human pandemics from humans all by themselves?Human pandemics can begin in humans. HIV is one such pandemic. Though the virus spread from other primates to humans a few 1,000 years ago, it was the change in circumstance that led to the current pandemic.

But there are reasons pandemics begin in other species. When a disease is particularly deadly, it kills the host too fast for the infection to spread. So milder disease is often selected for genetically since it spreads more easily. That makes deadly pandemics less likely to emerge in the species being killed.

In the case of bird flu, though domestic birds are dying at very high rates, many wild birds with the same infection are not, and neither are pigs which is also a problem. The virus then has the opportunity to evolve into something that spreads among one species while becoming very lethal to another. When events occur that allow the virus to jump to another species, the lethality can be very high. After the pandemic runs its course, milder organisms are selected which don't kill the host.

In other words, the mechanisms of natural selection have given us the recurring deadly bird flu pandemics. It just so happens human and bird genetics are a set up for this particular virus to evolve in birds and occasionally jump to humans. Domestic birds are a big part of the equation since close human bird contact occurs there.

By the way, we also get bird flu virus infections that are not deadly. They are now referred to as low pathogenic avian influenza viruses, LPAI. The current H5N1 is considered a high pathogenic avian influenza virus, HPAI.

Ken G
2005-Oct-16, 10:01 AM
In the case of bird flu, though domestic birds are dying at very high rates, many wild birds with the same infection are not, and neither are pigs which is also a problem.

I see, I had forgotten that.

After the pandemic runs its course, milder organisms are selected which don't kill the host.


Thank you, this is very insightful. A lot of things are making more sense. Also, I reach two conclusions based on what you said. Can you confirm:
1) there should be a maximum-threat kill percentage, perhaps near the 5% (?) of the 1918 virus (too high and the virus can't spread quickly enough to cause a pandemic, too low and it won't lead to that many deaths).
2) the people who die from a virus are less of a threat to the overall population than those with immunity, as the latter are more responsible for its spread. Not that I mean to imply any culpability or blame, we all spread viruses and it's not anyone's fault unless done intentionally.

Also, I wonder if the issue with birds might go beyond the genetic relationships to humans, to include the simple fact that birds fly? Since people fly now, a lot more than in 1918 (thuogh not as much as birds of course), maybe birds are not as crucial a component of the equation going forward?

Gillianren
2005-Oct-16, 09:52 PM
Hey, I fly more than a bird.

Always providing, of course, that said bird is either a penguin or an ostrich.

Ken G
2005-Oct-17, 01:46 AM
Hey, I fly more than a bird.


:whistle:

beskeptical
2005-Oct-17, 07:19 AM
I... Can you confirm:
1) there should be a maximum-threat kill percentage, perhaps near the 5% (?) of the 1918 virus (too high and the virus can't spread quickly enough to cause a pandemic, too low and it won't lead to that many deaths).Well there are many factors involved so one cannot look at a single factor in isolation. HIV is close to 100% fatal and look how far it is spreading.


2) the people who die from a virus are less of a threat to the overall population than those with immunity, as the latter are more responsible for its spread. Not that I mean to imply any culpability or blame, we all spread viruses and it's not anyone's fault unless done intentionally.Again, it depends on period of communicability, rate of viral shedding, number of contacts with susceptible persons and so on. With SARS there were certain individuals that shed a lot more virus than others. Whether or not they lived or died may not have had much affect on the number of persons they infected.


Also, I wonder if the issue with birds might go beyond the genetic relationships to humans, to include the simple fact that birds fly? Since people fly now, a lot more than in 1918 (thuogh not as much as birds of course), maybe birds are not as crucial a component of the equation going forward?Once a flu pandemic begins in humans, birds no longer play a role. And the fact we have air travel now will definitely have an impact should we get a virus similar to 1918 influenza.

Ken G
2005-Oct-17, 07:25 AM
Oh I see, the mutation that allows it to go person-to-person would happen in a person, not in a bird, correct? Could you imagine countries closing their borders if the virus started going person to person somewhere?

Tunga
2005-Oct-17, 07:28 PM
I just hope the next time a pandemic occurs, that we do not blindly attribute the cause without due diligence. Large areas of medical science still borders on the unknown. And one man's retrovirus is another man's mycobacteria.

http://www.sumeria.net/aids/001PDF~1.PDF

aurora
2005-Oct-17, 08:53 PM
Could you imagine countries closing their borders if the virus started going person to person somewhere?

Yes. Even if they didn't, people will voluntarily reduce travel (remember SARS?)

Within a country, there may be specific limits on some kinds of travel. Individuals who have been exposed would be asked to voluntarily confine themselves to their home.

beskeptical
2005-Oct-17, 10:11 PM
I just hope the next time a pandemic occurs, that we do not blindly attribute the cause without due diligence. Large areas of medical science still borders on the unknown. And one man's retrovirus is another man's mycobacteria.

http://www.sumeria.net/aids/001PDF~1.PDFWith new lab techniques that allow easy genetic ID and mapping of organisms, this is much less likely to happen.

suntrack2
2005-Oct-21, 04:15 PM
can the sea creatures spread the unknown viruses?

beskeptical
2005-Oct-22, 06:47 PM
can the sea creatures spread the unknown viruses?
No reason it wouldn't be possible.

NanC
2005-Oct-22, 10:58 PM
I have not heard of this resurrecting of the other virus to fight the new one. Most of you seem well read on it but I don't have background information. Can somebody post a link that catch me up to speed?

beskeptical
2005-Oct-23, 08:21 PM
I have not heard of this resurrecting of the other virus to fight the new one. Most of you seem well read on it but I don't have background information. Can somebody post a link that catch me up to speed?

News story with links to original articles (http://www.scidev.net/news/index.cfm?fuseaction=readnews&itemid=2397&language=1)

html version of Science journal article (http://www.sciencemag.org/cgi/content/full/310/5745/77?ijkey=z1ayspFzqhWVc&keytype=ref&siteid=sci)
pdf version of Science journal article (http://www.sciencemag.org/cgi/reprint/310/5745/77.pdf?ijkey=z1ayspFzqhWVc&keytype=ref&siteid=sci)

pdf version of article in Nature (http://www.scidev.net/pdffiles/nature/nature04230.pdf)

Blob
2006-Nov-08, 10:09 AM
Hum,
i watched a Horizon program last night about bird flu.
One thing i noticed in the program was that the anti viral drugs that we have now won't actually do anything. Once bird flu gets into the general environment and can't be contained; the drugs will just delay the peak, and just as many people will eventually die.

Also...


Circumstantial evidence links Spanish flu and encephalitis lethargica (http://en.wikipedia.org/wiki/Encephalitis_lethargica), or sleeping sickness
Both pandemics were globally distributed and closely related in time. Local, regional, and national epidemics of Spanish flu preceded "similar sized" outbreaks of encephalitis lethargica. Deaths were greatest in the 20- to 40-year age groups for Spanish flu and in the 20- to 50-years for sleeping sickness.
A large number of victims of encephalitis lethargica had had influenza in 1918.

Read more (http://www.thestar.com/NASApp/cs/ContentServer?pagename=thestar/Layout/Article_Type1&c=Article&cid=1135941240915&call_pageid=968256290204&col=968350116795)

Blob
2006-Nov-15, 08:01 PM
SCIENTISTS FIND MUTATIONS THAT LET BIRD FLU ADAPT TO HUMANS

By comparing influenza viruses found in birds with those of the avian virus that have also infected human hosts, researchers have identified key genetic changes required for pandemic strains of bird flu.
The new work, reported in the Nov. 16 issue of the journal Nature, illustrates the genetic changes required for the H5N1 avian influenza virus to adapt to easily recognise the receptors that are the gateway to human cells.

Read more (http://www.news.wisc.edu/releases/13198.html)

NEOWatcher
2006-Nov-15, 08:09 PM
One of the big problems with the bird flu is that it causes chirpies.
Unfortunately, that's untweetable.

Blob
2006-Nov-29, 12:52 AM
It sounds like a campy ‘50s horror movie (“It Came from the Ice!”), but a Bowling Green State University biologist believes it's a very real possibility. Dr. Scott Rogers is talking about the potential for long-dormant strains of influenza, packed in ice in remote global outposts, to be unleashed by melting and migratory birds.

"We've found viral RNA in the ice in Siberia, and it's along the major flight paths of migrating waterfowl," whose pathways take them to North America, Asia and Australia, and interconnect with other migratory paths to Europe and Africa, explains Rogers.

Viruses, he says, can be preserved in ice over long periods of time, then released decades later when humans may no longer be immune to them. For instance, survivors of the worldwide flu pandemic of 1918 had immunity to the responsible strain—called H1N1—but that immunity has died with them, meaning a recurrence "could take hold as an epidemic."

Read more (http://www.bgsu.edu/offices/mc/news/2006/news25091.html)

pranab
2006-Dec-04, 12:39 PM
During 20th century three Influenza pandemic took Place
* Of worst is 1918-19, where 40-50 million people died
*in the 21st centurythe pandemic influenza took place with A/H5N1 influenza virus
* This virus expanded the geographical distribution - In Asia, Middle East, Africa, Europe & Amerca
Vaccine are available
1) REverse getentic approach Tecnology generated a virus that expressed the Haemagglutinin & Neuraminadase gene from A/H5N1 virus, when inserted into egg adopted vaccine virus strain A/PR/8/34. It is Known as A/ Vietnam/1203/2004 vaccine. It can elicit seroconversion rate upto 54% after a dose regeme at 90ug per dose
2) In Phase-1 Trial still there is another vaccine- It is named as A/ Vietnam/1194/2004 vaccine with or without Aluminium Hydroxide Adjuvant- This vaccine showed 66.7% Haemaglutination inhibition seroconversion.
3) We do not have still a highly immunogenic vaccine for this virus
4) We do not Know wheteher antibodies evoked by these vaccine can protect a person from pandemic and long lasting one
Professor pranab Kumar Bhattacharya
Mrs Dahlia Mukherjee
www.unipathos.com

pranab
2006-Dec-08, 01:16 PM
Transmission of the Virus * Not all the flue virus have same transmission properties The virus causing Avain Flue spreads by Faeco-oral route
* Human contracting this condition acquire it as a result of contact with infected poultry either by air borne spread or their faeces or or contamination during their food preperation
* people typically acquire flue by inhaling the virus or by being direct contact with respiratory tract secreation of people who are infected
* Healthy adults shed virus 1 day before onset of symptoms and continue to shed for 5-7 days or more. Children shed longer and immunocompromised people till longer
Species affected by the flue virus Flue virus can affect many species including horses, whales, seals, pigs, birds, ducks, wild fowel
in 1983 epedemic in poultry occured by H5N2 in USA and associated with 13 million poultry death

How Much Deadly virus
Spanish flue in 1918-19 by H1N1 resulted 2,50,000 death in Uk, Asian Flue in 1957-58 by H2N2 resulted 33,ooo death and HongKong flue resulted 30,000 death of humans
Avain Flue in Human
Human infection with H5N1 was first described in HongKong in 1997- 18 people were affected- 6 people died
H5N1 virus strain does not currently pass from human to human efficiently but it can mutate in to a human pandemic form and then the real problem will arise. WHO says 2-4.7 million death based on 1968 pandemic
* A new Flue virus emerged H7N7 infection was described in Dutch poultry workers that caused death of a Veternary surgeon
Symptoms & complication= Dry Cough, Muscle pain, Sore Throat, Raised Temperature, Head ache, Feeling weak. Complications= Otities Media, Influenza pneumonia &ARDS, Secondary bacterial bronchities & Pneumonia, Rarely Encephalities
Drugs= Neuraminadase inhibitors
1) Oseltamivir( Tamiflue) and Zanamavir are the two drugs which are backbone of mass treatment for this virus. however not specific for the virus. Have many side effects
2) Vaccine as stated in early postings
Professor pranab Kumar Bhattacharya
Mrs Dahlia Mukherjee
www.unipathos.com

antoniseb
2006-Dec-22, 09:07 PM
Hi pranab,

I had to remove your post which had a copyright on it.
We aren't allowed to repost copyrighted material like that.
Please don't do this again.

sarongsong
2006-Dec-24, 08:40 AM
...a virus that has so far only killed sixty-four people worldwide...New tally:
December 23, 2006
...The latest [2] cases brings to 17 the total number of Egyptians infected, including seven who were killed by the virus...the H5N1 strain has killed 154 people worldwide, according to the World Health Organisation. Breitbart (http://www.breitbart.com/news/2006/12/23/061223194046.mcmjylzx.html)

beskeptical
2006-Dec-25, 09:58 AM
Transmission of the Virus * Not all the flue virus have same transmission properties The virus causing Avain Flue spreads by Faeco-oral route
* Human contracting this condition acquire it as a result of contact with infected poultry either by air borne spread or their faeces or or contamination during their food preperation
* people typically acquire flue by inhaling the virus or by being direct contact with respiratory tract secreation of people who are infected
* Healthy adults shed virus 1 day before onset of symptoms and continue to shed for 5-7 days or more. Children shed longer and immunocompromised people till longer....I'm not sure of the point of this post but I can elaborate a bit on the current infectivity of H5N1 which isn't exactly clear here.

Poultry and other bird species have disseminated influenza virus when they have H5N1 infection. The virus can be found in most if not all tissues. Therefore the bird droppings do indeed contain virus as does the blood and meat.

The human activities that resulted in infection involved slaughtering the birds without protection, drinking raw duck blood and other forms of consuming uncooked parts, and entering the chicken coop such as kids do to retrieve eggs. These activities result in exposure to high viral loads which is what it currently takes to get infected.

The human cells which the H5N1 virus is more efficient in are in the lower respiratory tract. Human flu is very efficient in upper respiratory tract. So current human infections are not producing large viral loads when those infected cough and exhale.

However, there are now a number of different and still lethal strains of H5N1 circulating. They are referred to as clades and sub-clades. So far, none of the genetic changes appear to be at the location on the H5N1 RNA where it is expected to result in more efficient replication in human upper airway cells. Additional research though has shown that for current human influenza strains, genetic drift goes on for some time before a new strain emerges.

So we remain in a holding pattern. There is no certainly the virus will or will not emerge as a human pandemic. I certainly haven't breathed any sighs of relief. I think it is easy for people to think that because it hasn't happened yet it isn't going to.

Unfortunately, the situation has worsened a tad in the last few weeks. While the cases of new outbreaks among birds had subsided, new outbreaks have occurred again in a wide area covering countries from Egypt to Nigeria to S Korea (http://www.promedmail.org/pls/askus/f?p=2400:1001:5314015920096701208::NO::F2400_P1001 _BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,35576) including more human cases an another death.

The fact this disease has only killed 155 (one more died 12/24) people should not lead one to think the preparation is excessive. You will wish it had been excessive and realize it wasn't even adequate if H5N1 is the next influenza pandemic that occurs.