The H5N1 strain of influenza - often referred to as bird flu - is first known to have jumped from chickens to humans in 1997. Since 2004 it has ripped through poultry and wild bird populations across Eurasia, and had a 53% mortality rate in the first 147 people it is known to have infected. Health authorities fear this strain, or its descendent, could cause a lethal new flu pandemic in people with the potential to kill billions.
Flu has been a regular scourge of humanity for thousands of years. Flu viruses each possess a mere 10 genes encoded in RNA. All of the 16 known genetic subgroups originate in water birds, and especially in ducks.The virus is well adapted to their immune systems, and does not usually make them sick. This leaves the animals free to move around and spread the virus - just what it needs to persist.
But sometimes a bird flu virus jumps to an animal whose immune system it is not adapted to.
A handful of children and young adults each year succumb to to influenza, however. Last year the CDC reported 68 children killed by `flu' in the United States. Over the past few weeks we've been getting reports of a few children dying in Australia from influenza.
The CDC is still trying to build an accurate picture of an average flu season in the United States but it is difficult because doctors do not often even test patients for respiratory diseases, much less report them to the federal government.
But because health experts suspect a pandemic -- a serious global epidemic -- of influenza is potentially imminent, the CDC is struggling to gather as much information as possible about flu now.
Queensland Health has confirmed that a former soldier and father of three died after developing the same strain of `flu that killed a four-year-old boy in Brisbane last week.
Glen Kindness, 37, of Narangba, north of Brisbane, died less than three hours after he was taken to Blackwater Hospital in central Queensland on Tuesday.
... an agency spokesperson said tests had confirmed that he had, at some point, been suffering from influenza A, a virulent strain of the virus.
Mr Kindness's wife, Kathleen, said she understood he had died of pneumonia and septicaemia, which came on top of the `flu.
"He had multiple organ failure,"she told ABC Radio.
But she said the death came as a surprise as her husband was very fit.
"He was extremely fit, you know, he always looked after himself.
Essay from Avian Flu Diary with permission from the author:
Saturday, August 11, 2007
Deus Ex Machina
# 1055
The past few days the biggest news on the Avian flu front has come from the announcement that researchers have isolated an antibody that might work against multiple strains of the H5N1 virus. This, we are told, may pave the way to a preemptive avian flu vaccine.
This report from the The Standard of Hong Kong is pretty typical, although to their credit, this paper has dropped the `beat bird flu before it begins' headline that many newspapers have used over the past couple of days.
Still, the underlying message is we are on the verge of having a vaccine that can prevent a pandemic. But are we really?
First the article, then a reality check.
New vaccine to jump gun on avian flu
Researchers studying bird flu viruses believe they may have found a way to vaccinate people before a feared influenza pandemic.
Experts have long said there is no way to vaccinate people against influenza until a strain evolves. That could mean months or years of disease and death before a vaccination campaign.
But a team at the US National Institute of Allergy and Infectious Diseases in Maryland and the Emory University School of Medicine in Atlanta said they may have found a shortcut.
The reason we don't have a vaccine available to stop an influenza pandemic, we are told, is because you can't start manufacturing one until the exact pandemic strain is identified. Viruses mutate, and a vaccine based on an older virus might not be effective against a mutated strain.
And that is true, as far as it goes.
But of course, that isn't the only reason. It is just the easiest one for governments to explain. Most people understand this problem, and accept that vaccine production can't begin until after a pandemic erupts. It sucks, but they accept it.
But what if you could remove that barrier? What if you could produce a vaccine in advance that had a good chance of being effective against a mutated H5N1 virus, would the governments of the world do so?
Could they, even if they wanted to?
And if they did, would they really be willing to administer this experimental vaccine to billions of people prophylactically in order to `beat a pandemic before it starts'?
Using today's egg-based technology, we have the global capacity to produce about 500 million trivalent doses of vaccine a year. If a monovalent vaccine could be produced instead, then theoretically 1.5 billion doses might be produced over 12 months.
Of course, no other influenza vaccines could be produced during this time, and without a seasonal flu vaccine, that would probably lead to many thousands of deaths from non-pandemic flu.
But, if all of our resources were devoted to this new vaccine, since most vaccines have required 2 shots, 30 days apart, this might be enough to inoculate 750 million people. Or roughly 12% of the world's population.
Hmm. I'm beginning to sense a problem here. Nearly 90% of the world's population still wouldn't see a vaccine in the first year.
Complicating matters is the fact that most vaccines (and I'm assuming this would hold true for this new one, as well), lose their effectiveness after a few months. The immune response wears off over time. Perhaps not completely, but the level of protection begins to drop after 6 months or so.
And that means that booster shots, every year or so, may be required. That would drastically cut down on the number of people that could be inoculated in subsequent years.
Now perhaps the new cellular based manufacturing techniques currently under development will solve this production problem. They hold the promise of greatly enhancing our ability to produce vaccine in quantity. While not quite ready for prime-time, these techniques could be online in the next few years.
But then comes the decision of whether to inoculate people with an experimental vaccine against an influenza strain that may, or may not, cause the next pandemic. As many of you will recall, that decision was made in 1976 with the Swine Flu, and the results were less than satisfactory.
Severe reactions to influenza vaccines are believed to be extremely rare, despite the bad name the Swine Flu vaccine earned 30 years ago. Still, if only 1 person in 100,000 experienced a problem, that could equate to nearly 3000 potential lawsuits in the United States alone.
That is a lot of liability.
It would take an enormous amount of political courage to spend billions of dollars to divert our current seasonal influenza vaccine production to an experimental vaccine for a pandemic strain, and then risk prophylactically inoculating large segments of our population before a pandemic erupted.
The lack of a seasonal vaccine would certainly cost lives. And any adverse side effects to this experimental vaccine would be sensational fodder for the press, just as it was in 1976. The decision to put all of our eggs into an experimental vaccine basket would be very tough for any government to make.
We've been conditioned by movies and television shows to believe that scientists can, at the last minute, create some medical miracle that will always save us from the brink. It's a nice fantasy, but basically it's a plot device used to wrap up a dramatic presentation in an hour or two.
It has, however, a long history.
In ancient Greek plays, it was common to have an improbable character or event introduced suddenly at the end of a play to resolve whatever thorny problem remains. Deus Ex Machina, literally God out of the machine, comes from the plot device of lowering a God from the rafters onto the stage to solve all of the problems.
There are a lot of problems that would have to be overcome before any scientific breakthrough in vaccine research could be used to prevent a pandemic. They aren't impossible to solve, of course.
But we would need time, luck, and immense political courage on the part of our leaders to make it happen.
And a God descending from the rafters wouldn't hurt, either.
AN EMERGENCY response team rushed to a Brisbane western suburbs nursing home yesterday to administer flu vaccine, after carers feared a widespread outbreak was in the making.
Queensland Health has confirmed two cases of influenza A and two suspected cases at the nursing home, which it would not name because it is a private facility.
Queensland Chief Health Officer Dr Jeannette Young said the response team made the anti-viral drug Tamiflu available to patients and staff.
Three new cases of the deadly H5N1 strain of bird flu have been detected in poultry on farms in the west African nation of Togo, a report said Saturday.
The new cases were found in dead birds on farms in the Lacs, Golfe and Zio regions east of the capital Lome, national television reported.
In late June, testing confirmed the presence for the first time in Togo of the H5N1 strain in poultry in Sigbehoue, 45 kilometres (30 miles) east of the capital.
About 8,000 poultry birds were slaughtered in the area and local poultry markets were closed. Togolese authorities also stepped up controls on poultry imports.
Of course, all this laboratory tinkering with primal forces of nature should also make one (justifiably) uneasy. Witness the recent "DOH!" with our friends the British. Within the past few days it has been disclosed that one single, solitary lab goof is apparently responsible for the accidental re-release of foot and mouth disease in the UK. And now, to top things off, an employee of the facility has contracted Legionnaire's Disease.
The World Organization for Animal Health says foot-and-mouth warrants the highest containment level possible. Among its recommendations are that sewage be treated to ensure infectious material is destroyed and that staff shower and change clothes before leaving the lab....
Concerns about biosafety were triggered after three laboratory-related outbreaks of Severe Acute Respiratory Syndrome in Singapore, Taiwan and China in 2003 and 2004. In Singapore and Taiwan, lab workers inadvertently infected themselves. That was also the case in China, where the infection spread from two lab workers to seven family members and contacts outside the lab.
In 2005, scientists worldwide scrambled to avert a possible global flu outbreak by destroying samples of the 1957 flu pandemic virus that were accidentally sent to 5,000 labs in 18 countries.
And now, let us turn to the Overview: International Conference on Biosafety and Biorisks...
(Dr. Robert) Webster explained that there is significant evidence that the 1977 H1N1 pandemic was due to an accidental lab release, as it was genetically identical to a strain that circulated naturally decades before.
Indonesia has recorded another death from bird flu...
The 29-year-old woman from a village in western Bali had a high fever when she was admitted to hospital. She died yesterday from multiple organ failure.
... The woman's five-year-old daughter also died recently after playing with chickens, but it's unclear if bird flu was responsible.
And a two-year-old girl, a neighbour of the victims, was admitted to hospital on Sunday, and is also suspected of being infected....
what's worrying the authorities... is...the people in this village...when they had an outbreak of infected chickens what they were doing was feeding them to pigs, the sick and the dying chickens, rather than burning them as they're required to do by law.
Now, the worry there is that if the infected chickens are fed to pigs, this could provide a vector, a conduit for the disease to mutate, and affect humans....and that's of particular concern to the National Centre, and that's one of the reasons, as we speak, they're heading there now to close off this village and completely isolate it.
It is rather amazing to consider that they are closing off this village and isolating it. We have in the past heard of authorities using the Tamiflu Blanket, but closing off and isolating a village? That is most unusual.
The wild birds died in the middle of the summer, so the prior hypothesis of open water searches in the dead of winter, which was used to explain the widespread H5N1 in February, 2006 does not apply. Although H5N1 went largely undetected between June 2006 and June 2007, there is little evidence that H5N1 "disappeared" from wild bird population. Most positives before and after the "disappearance" were in resident birds...
The multiple positives in multiple locations in Germany, France, and the Czech Republic again raises serious questions about H5N1 surveillance systems in
neighboring countries, where endemic H5N1 in wild birds is a near certainty.
The eighth death from influenza A in Australia this season is a 48 year-old woman who was a receptionist in a private medical clinic. For a review of the Australia timeline of flu events since August 1, see this thread at PFI:
I don't always post links to Effect Measure including comments, but I will this time because the comments are interesting and worth reading. Sometimes posters over there can say some inappropriate things however, so I may end of editing this when I return from Maine on Monday. In the meantime, I hope everyone will get something out of some of the studies that are in the comment section, and hopefully I won't have to edit. Tom DVM is a retired (?) vet up in Canada, and has some
in post #101 indigo girl discusses the isolation of dangin tukadaya village where the first balinese human h5n1 cases was confirmed. while the extent of isolation in the village is unknown, over 5,000 chickens have been culled and the entire jembrana regency has been
temporarily "isolated" from other areas, by not allowing transportation of poultry into or out of the district.
In Bandung, Indonesia, a doctor was initially suspected of contracting bird flu from personal chickens that had died. Initial PCR tests for H5N1 were negative. The individual was given Tamiflu and is improving. They also are awaiting additional test results.
indigo girl
5,173 Posts
Even seasonal flu can be a killer:
http://afludiary.blogspot.com/2007/08/even-seasonal-flu-can-be-killer.html
Here is the kind of report that is puzzling:
http://www.brisbanetimes.com.au/articles/2007/08/10/1186530569702.html
(hat tip rick/PFI)