Avian Flu'

[GordMay]

Avian Influenza A (H5N1) Infection in Humans
The Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5

”An unprecedented epizootic avian influenza A (H5N1) virus that is highly pathogenic has crossed the species barrier in Asia to cause many human fatalities and poses an increasing pandemic threat. This summary describes the features of human infection with influenza A (H5N1) and reviews recommendations for prevention and clinical management presented in part at the recent World Health Organization (WHO) Meeting on Case Management and Research on Human Influenza A/H5, which was held in Hanoi, May 10 through 12, 2005.1 Because many critical questions remain, modifications of these recommendations are likely ...”

Read the full article from “The New England Journal of Medicine” (free):
http://content.nejm.org/cgi/content/full/353/13/1374
Includes lots of links to other free references.

[Alan Wheeler]

NZ has been aware of this potential threat for sometime and following it closely. This is seriuose as the virus is now only one mutation away from being a person to person transmitter. If this happens, authorities believe the virus will be found world wide within 14days. And of course, because the virus in a human carrying form doesn't exist yet, the is no vacine for it. The threat of this is so seriuose, that our government has stated that upon an outbreak, they will close the boarders to NZ. No one in, and no one out. Now that's a scary thought.

[CaptainK]

Well Wheeler,

I can understand that subject. I would not want that flu either. And I'm sure that I speak for the billions on this planet. When it comes to not wanting to die of something like that avian flu.

I just hope that, that will never come. At least not in our lifetime?

Regards,

Kevin
CaptainK

[CaptainK]

On Wednesday, October 5th 2005. U.S. president George W, Bush spoke to congress about having the U.S. military to help out with controlling the Avian Flu outbreak.

Should it ever reach the shores of the United States. Bush wants the military to set up quaratine zones, around cities. Or areas, around the populated, most heavily infected with the avian flu. A plan to try, to keep the avian flu from spreading to the rest of the country.

Other countries like New Zealand. And others, are in talks on developing their own plan, of actions, against a future pandemic. The H5N1 virus is a grandson strain, from the 1918 Spanish Influenza, virus strain. Mutated through the years to this present form of virus.

Only a step away. A pathogenic virus. Breathing around near other people. And other living beings. Could be spread to them as well. And the spreading goes from there.

Kevin
CaptainK

[GordMay]

Avian Influenza ~ H5N1:

Of the 15 avian influenza virus subtypes, H5N1 is of particular concern.

World Health Organization officials say the avian flu, often called the bird flu, was identified in animals, primarily poultry, last year in 10 countries, and is circulating in four: Thailand, Vietnam, Cambodia and Indonesia. When people are infected, it has a high mortality rate. These Asian countries have documented 55 cases in which the avian flu has jumped from birds to humans, and only one in which it was passed from human to human. Of the more than 50 who have been infected with the disease, more than 40 have died.

Two worrisome characteristics of all type A influenza viruses, including avian influenza, are that they have the ability to mutate and also swap genetic materials to merge. If more humans become infected over time, the more likely humans can serve as a "mixing vessel" for the emergence of a novel subtype that would become easily transmitted from person to person. This merging or antigenic "shift" can ultimately result in highly lethal human pandemics. Pandemics usually occur every 20 to 30 years, when the genetic makeup of a flu strain changes so dramatically that people have little or no immunity built up from previous flu bouts.

There have been three pandemics in the 20th century, all spread worldwide within a year of being detected.
- The worst was the Spanish flu in 1918-19, when as many as 50 million people worldwide are thought to have died, nearly half of them young, healthy adults. The - Asian flu pandemic of 1957 claimed nearly 70,000 lives in the United States and one million worldwide after spreading from China.
- In 1968, the Hong Kong flu pandemic is also said to have killed around one million.

From the World Health Organization (WHO) - September 29/05

Avian influenza – situation in Indonesia – update 32
http://www.who.int/csr/don/2005_09_29/en/index.html

and

Disease Outbreak News
http://www.who.int/csr/disease/avian_influenza/en/
Including outbreaks by year (‘05):
Poliomyelitis in Indonesia, Somalia, Ethiopia, Angola
Cholera in West Africa
Yellow fever in Burkina Faso and Côte d'Ivoire, Guinea
Japanese Encephalitis (JE) in India
Marburg haemorrhagic fever in Angola
and more ...

[CaptainK]

Your right Gord,

This avian flu could be the next "pandemic?" The USA is right now slowly making plans (contingency plans), for the military to quaratine areas with the highest number of cases.

Basically, President Bush wants the military to simply quaratine the people. So they can stop spreading it across our country.

I hope so. Cause, I hate the regular flu. And I hate getting sick. The last really bad resportory virus I had was the winter of 1998/99. In the month of Janurary of 1999. I had it really bad. I was almost hospitized, due to the high fever I had. It was at one point 107 F.

For anyones sake. I hope that no one on this forum would ever get this virus. Especially the ones who cruise through Asia? Cause those sailors, are more prone to being exposed to it first! And die, due to the severity, and mass numbers of people infected in those poorer countries.

I'm not saying those countries do not have good health care. But, maybe ok health care. But, what I'm saying is this: if there are huge fallouts of sick people. There are not enough nurses, and doctors to go around. No matter how much money you have. Period!

Well, good luck for everyone here, on the forum. Like I said. I would hate for anyone to get this virus. It seems to be pretty deadly.

Regards,

Kevin
CaptainK

[Talbot]

Birds with avian flu have just been discovered in Romania following annual migration.

Dont think it wont get to you, start thinking of strategies for dealing with the problem.

[ssullivan]

It's a good thing we all have boats!

It's very rare to get colds while out cruising full time, as you are exposed to few people outside of those aboard your vessel.

I think this community is already at some advantage. Of course, we don't have any type of defense against it being on our food, but other than that..... it should be better for us than the 9-5 office folks.

[CaptainK]

Dear Talbot & ssulivan,

To Talbot: You never know. Birds migrate north to south. And back and forth.


Then there's the jet setters. They fly overseas, often to areas like Asia. And into these areas where there is a possible epidemic.


Countires like China tends to keep their mouths shut, about plauges. Like they did with the SARs episode a few years back. I do not know why they would not let the rest of the wrold know about this. It's like they're paranoid. Afraid, that we'll come over there and take'em over. Or something.

To ssulivan: Good thing about sailing out at sea. Total isolation. The fewer people you meet. The better off the entire crew is. I also tend to noticed that while I was in the Navy.

When I served aboard ships. I was hardly that sick. But, when it came time for my rotation to serve on shore. I noticed how much more prone to getting sick I became.

Regards,

Kevin
CaptainK

[BC Mike]

Apparently there are only about four strains of chickens in North America, which is not much of a gentetic pool if something goes wrong.
My X farm boss new all about this stuff, I absorbed a little that trickled down to me.
Michael

[CaptainK]

Well BC Mike,

You used to work on a farm? And really. Only 4 breeds of chickens in North America?


Regards,

Kevin
CaptainK

[s/v 'Faith']

Think abou this for a second.

Alan Wheeler posted;

No one in, and no one out. Now that's a scary thought.

Would any cruising boat be able to get underway if there were a quaratine? Worse yet, what if you were 'out' and looking to come back home?

[GordMay]

From the New England Journal of Medicine: http://content.nejm.org/cgi/reprint/353/21/2209.pdf

”The Origins of Pandemic Influenza” — Lessons from the 1918 Virus
by Robert B. Belshe, M.D.

The completion of the genetic sequencing of the 1918 influenza A virus by Taubenberger et al.1 and the subsequent recovery of the virus by Tumpey et al.2 using reverse genetic techniques are spectacular achievements of contemporary molecular biology and provide important insights into the origin of pandemic influenza. The three pandemic viruses that emerged in the 20th century — the 1918 ("Spanish influenza") H1N1 virus, the 1957 ("Asian influenza") H2N2 virus, and the 1968 ("Hong Kong influenza") H3N2 virus — all spread rapidly around the world, but only the 1918 virus was associated with mortality measured in the thousands per 100,000 population.

In both 1957 and 1968, a new influenza virus emerged because of reassortment events involving two influenza viruses. The segmented genome allows each influenza A virus to exchange genetic material with other influenza A viruses. In 1957, dual infection of an individual animal — probably a human, but possibly another species, such as a pig — with an avian H2N2 influenza and a human H1N1 influenza resulted in the emergence of a new influenza virus containing the hemagglutinin, the neuraminidase, and the gene for one of the polymerase proteins (PB1) from the avian virus, along with the remaining five genetic segments from the human H1N1 influenza virus.

The new reassortant virus circulated in humans until 1968, when it was replaced by another reassortant virus, the H3N2 Hong Kong virus — created by the replacement of the hemagglutinin (H2) and polymerase (PB1) genes of the H2N2 virus with two new avian genes, H3 and a new PB1. Today, the descendants of this virus continue to cause the majority of influenza infections in humans (see diagram). Five of the genes of today's H3N2 influenza virus have their origin in the 1918 pandemic.

In 1918, an H1N1 virus closely related to avian viruses adapted to replicate efficiently in humans. In 1957 and in 1968, reassortment events led to new viruses that resulted in pandemic influenza. The 1957 influenza virus (Asian influenza, an H2N2 virus) acquired three genetic segments from an avian species (a hemagglutinin, a neuraminidase, and a polymerase gene, PB1), and the 1968 influenza virus (Hong Kong influenza, an H3N2 virus) acquired two genetic segments from an avian species (hemagglutinin and PB1). Future pandemic strains could arise through either mechanism.

The startling observation of Taubenberger et al. was that the 1918 virus did not originate through a reassortment event involving a human influenza virus: all eight genes of the H1N1 virus are more closely related to avian influenza viruses than to influenza from any other species, indicating that an avian virus must have infected humans and adapted to them in order to spread from person to person. Thus, pandemic influenza may originate through at least two mechanisms: reassortment between an animal influenza virus and a human influenza virus that yields a new virus, and direct spread and adaptation of a virus from animals to humans.

The concern at present relates to the widespread epidemic of avian H5N1 influenza in domestic fowl, as well as wild birds, with sporadic transmission to humans. In the past decade, numerous instances of bird-to-human transmission have been recognized (see table); although we have only recently become aware of them, these events are surely not new. What is new is the broadening of the range of avian and nonavian species that have become infected with the current H5N1 virus.3

The characterization of the recovered 1918 virus in tissue culture and mice reveals at least two unique qualities. This virus is able to replicate and form plaques on tissue-culture monolayers in the absence of the protease trypsin. Normally, a protease such as trypsin is required to activate the hemagglutinin in order to initiate the infection of tissue culture, but the 1918 virus can activate its own hemagglutinin through the action of neuraminidase, either directly or indirectly (possibly by neuraminidase's binding of a host protease). The exact mechanism by which the neuraminidase takes on the protease activity has not been determined.

In addition, the 1918 virus is 100 times as lethal in mice as any other human influenza virus; the median lethal dose (LD50, or 103.5 to 3.75 median egg infectious doses [EID50]) is low, and the virus replicates rapidly so that high titers (>107 EID50 per milliliter) are found in the lungs of infected mice. High virus inocula result in the death of mice as early as three days after they have been infected. The 1918 virus was susceptible to the adamantine compounds (amantadine and rimantadine) and neuraminidase inhibitors (oseltamivir and zanamivir), and the availability of the recovered virus will facilitate studies of other therapeutics. For example, the vigorous release of cytokines in mice infected with the 1918 influenza virus is associated with rapid onset of pulmonary disease and death. Compounds that block the action of specific cytokines can now be evaluated as therapeutics that might help to reduce the mortality associated with pandemic influenza.

It is not possible to know whether the current H5N1 is capable of adapting to humans so that it can spread with high efficiency through low-titer aerosol transmission to initiate an influenza pandemic. However, Taubenberger et al. provide some guidance on the genetic changes that might be required for such an event. The role of PB1 must be critical, since in both 1957 and 1968, this polymerase gene was transferred along with the hemagglutinin during reassortment. By comparing the consensus sequence of the three avian influenza polymerase genes PA, PB1, and PB2 with the 1918 sequence, as well as with more contemporary influenza viruses, Taubenberger et al. have identified four amino acids of PA, one of PB1, and five of PB2 that are found in human influenza viruses (including the 1918 virus) but generally not in avian influenza viruses. In two instances, these amino acids are found in nuclear localization signaling regions, suggesting that some or all of these amino acid differences are critical for the virus to adapt to humans.

The genetic sequences of the 1997 Hong Kong H5N1 virus and the 2004 Vietnam H5N1 virus reveal that several human isolates of these viruses contain one of the five amino acid changes in PB2 that have been identified as important to the ability of the 1918 virus to infect humans. This finding suggests that several additional genetic changes must occur before these viruses will begin to spread efficiently from person to person. The genetic sequences of avian viruses may provide a window through which to monitor these sporadic transmissions for the potential of the viruses to adapt to humans. The occurrence of additional genetic changes in the avian H5N1 virus circulating in birds that match the consensus sequence for PA, PB1, or PB2 in human influenza would be cause for heightened concern.

On the basis of the rates of replacement of amino acids, Taubenberger et al. estimated that avian influenza polymerase genes had been circulating in humans as early as 1900. If this estimate is correct, then monitoring of the sequences of viruses isolated in instances of bird-to-human transmission for genetic changes in key regions may enable us to track viruses years before they develop the capacity to replicate with high efficiency in humans. Knowledge of the genetic sequences of influenza viruses that predate the 1918 pandemic would be extremely helpful in determining the events that may lead to the adaptation of avian viruses to humans before the occurrence of pandemic influenza. We could then conduct worldwide surveillance for similar events involving contemporary avian viruses.


Source Information

Dr. Belshe is a professor of medicine, pediatrics, and molecular microbiology in the Division of Infectious Diseases and Immunology, Department of Internal Medicine, Saint Louis University, St. Louis.

An interview with Dr. Belshe can be heard at www.nejm.org


References

1. Taubenberger JK, Reid AH, Lourens RM, Wang R, Jin G, Fanning TG. Characterization of the 1918 influenza virus polymerase genes. Nature 2005;437:889-893. [CrossRef][Medline]
2. Tumpey TM, Basler CF, Aguilar PV, et al. Characterization of the reconstructed 1918 Spanish influenza pandemic virus. Science 2005;310:77-80. [Abstract/Full Text]
3. The Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5. Avian influenza A (H5N1) infection in humans. N Engl J Med 2005;353:1374-1385. [Full Text]

[BC Mike]

The problem in North America is the lack of variety in the gene pool. The problem is worse for turkeys. I am giving you this second hand, I am not the brains in the farming department but my X is. You will have to look it up if you want to know more.
This has been a problem for a while, it did not happen last week.
Michael

[CaptainK]

Jakarta: Avian Flu Virus 'All Over City'
by J. Grant Swank, Jr.
Dec 2, 2005


Fear is spreading. So is the bird flu.
In Jakarta, the Indonesian capital, officials admit that "it's very serious. Based on our research, the virus has spread all over the city."

In one province, a man was taken to the hospital when saying he had a high fever, the AP reports. He was then taken to isolation. However, he said he needed to get some personal belongings back at his home.

He left the hospital and never returned. Before leaving hospital care, he informed the staff that he had become ill after he had slaughtered his bird flu sick poultry.

More than millions of birds have been killed in Indonesia due to the infection.


Indonesia has not been all that open with some of its detail nor willing to "carry out mass slaughters, citing a lack of money. But affected farmers were Friday offered some compensation."

In Indonesia's 30 provinces, 23 have been found to have the H5N1 virus. Seven humans have died from the virus.

The President stated to media last week that "domestic Tamiflu production was needed as the country's current inventory was insufficient."

Even then, no one can prove that the mutant virus would be overcome with any vaccine now available. Scientists are working to locate such a vaccine; however, it is difficult to predict the constituency of the mutant virus and thereby difficult to finalize a vaccine to attack it successfully.

"Authorities Friday also destroyed 400 fowl in a residential area of Jakarta near the home of a young girl who died from the disease."