Expert warns of misunderstanding behind 1918 flu

[AlaskaDenise]

Re: Expert warns of misunderstanding behind 1918 flu

The Doctor :: A Prediction for the Pandemic in the US this coming Fall

by: The Doctor
Fri Jun 19, 2009 at 20:39:01 PM EDT

A/(novel)H1N1 is very likely to acquire a change in both the 627 and 274 genetic sequences meaning that when it returns to the northern hemisphere in the fall it will be both more virulent and Tamiflu resistant.

The current novel virus has an avian sequence at 627. This sequence preferentially reproduces in the avian nasal passage that has an average temperature of about 35 degrees C. The human nose is cooler, 33 degrees C on average. Some, including Dr. Henry Niman say that one reason the novel virus continues to flourish in the northern hemisphere this summer is because it has this gene segment.

On 10Jun2009, in Shanghai, Chinese public health officials confirmed the isolation of a novel H1N1 strain that possessed the seasonal H1N1 flu 627 code that prefers to reproduce at 33 degrees C, the average temperature within the human nose during winter. Since the novel virus was isolated from a patient in Shanghai, this means that it is already in wide circulation within China and has almost certainly spread regionally if not globally by now.

Since the novel pandemic strain is co-circulating in the southern hemisphere with seasonal flu, especially the Tamiflu resistant H1N1, there is a very high likelihood that the novel strain will obtain the 274 genetic sequence from seasonal H1N1 that conveys Tamiflu resistance.

So, what do these two predictions amount to? The 627 acquisition means the novel flu will be much more infective in the fall than is is now in the northern hemisphere.

The acquisition of 274 means that the novel flu will not be sensitive to Tamiflu meaning that this anti-viral treatment will not be an effective measure against it.

Grattan Woodson, MD

http://www.newfluwiki2.com/diary/3480/a-prediction-for-the-pandemic-in-the-us-this-coming-fall

[Snicklefritz]

Re: Expert warns of misunderstanding behind 1918 flu

Is it possible that what we thought about 627 is incorrect, or perhaps incomplete?

If I understand correctly, the virus has an avian PB2 and, currently, does not have the E627K polymophism. And, that is offered as a possible reason the virus is so succesful in the Northern Hemisphere summer. Yet, the virus is doing quite well in the Sounthern Hemisphere winter as well as the Northern Hemisphere summer. Seems not so black and white as we (or maybe just me) imagined?

[AlaskaDenise]

Re: Expert warns of misunderstanding behind 1918 flu

... In other words, what experts are taking the position that will see another wave of much greater severity akin to the 1918 experience?

Swine Flu: H1N1 Virus More Dangerous Than Suspected, Except To Survivors Of The 1918 Pandemic Flu Virus

ScienceDaily (July 14, 2009) ? A new, highly detailed study of the H1N1 flu virus shows that the pathogen is more virulent than previously thought.

Writing in a fast-tracked report published July 13, 2009 in the journal Nature, an international team of researchers led by UW-Madison virologist Yoshihiro Kawaoka provides a detailed portrait of the pandemic virus and its pathogenic qualities.

In contrast with run-of-the-mill seasonal flu viruses, the H1N1virus exhibits an ability to infect cells deep in the lungs, where it can cause pneumonia and, in severe cases, death. Seasonal viruses typically infect only cells in the upper respiratory system.

"There is a misunderstanding about this virus," says Kawaoka, a professor of pathobiological sciences at the UW-Madison School of Veterinary Medicine and a leading authority on influenza. "People think this pathogen may be similar to seasonal influenza. This study shows that is not the case. There is clear evidence the virus is different than seasonal influenza."

The ability to infect the lungs, notes Kawaoka, is a quality frighteningly similar to those of other pandemic viruses, notably the 1918 virus, which killed tens of millions of people at the tail end of World War I. There are likely other similarities to the 1918 virus, says Kawaoka, as the study also showed that people born before 1918 harbor antibodies that protect against the new H1N1 virus.

And it is possible, he adds, that the virus could become even more pathogenic as the current pandemic runs its course and the virus evolves to acquire new features. It is now flu season in the world's southern hemisphere, and the virus is expected to return in force to the northern hemisphere during the fall and winter flu season.

To assess the pathogenic nature of the H1N1 virus, Kawaoka and his colleagues infected different groups of mice, ferrets and non-human primates ? all widely accepted models for studies of influenza ? with the pandemic virus and a seasonal flu virus. They found that the H1N1 virus replicates much more efficiently in the respiratory system than seasonal flu and causes severe lesions in the lungs similar to those caused by other more virulent types of pandemic flu.

"When we conducted the experiments in ferrets and monkeys, the seasonal virus did not replicate in the lungs," Kawaoka explains. "The H1N1 virus replicates significantly better in the lungs."

The new study was conducted with samples of the virus obtained from patients in California, Wisconsin, the Netherlands and Japan.

The new Nature report also assessed the immune response of different groups to the new virus. The most intriguing finding, according to Kawaoka, is that those people exposed to the 1918 virus, all of whom are now in advanced old age, have antibodies that neutralize the H1N1 virus. "The people who have high antibody titers are the people born before 1918," he notes.

Kawaoka says that while finding the H1N1 virus to be a more serious pathogen than previously reported is worrisome, the new study also indicates that existing and experimental antiviral drugs can form an effective first line of defense against the virus and slow its spread.

There are currently three approved antiviral compounds, according to Kawaoka, whose team tested the efficacy of two of those compounds and the two experimental antiviral drugs in mice. "The existing and experimental drugs work well in animal models, suggesting they will work in humans," Kawaoka says.

Antiviral drugs are viewed as a first line of defense, as the development and production of mass quantities of vaccines take months at best.


--------------------------------------------------------------------------------

Journal reference:

1.Itoh, Y. et al. In vitro and in vivo characterization of new swine-origin H1N1 influenza viruses. Nature, July 13, 2009 DOI: 10.1038/news.2009.680

http://www.sciencedaily.com/releases/2009/07/090713212231.htm

[Mamabird]

Re: Expert warns of misunderstanding behind 1918 flu

Is it possible that what we thought about 627 is incorrect, or perhaps incomplete?

If I understand correctly, the virus has an avian PB2 and, currently, does not have the E627K polymophism. And, that is offered as a possible reason the virus is so succesful in the Northern Hemisphere summer. Yet, the virus is doing quite well in the Sounthern Hemisphere winter as well as the Northern Hemisphere summer. Seems not so black and white as we (or maybe just me) imagined?

The Lysine at position 627 of PB2 allows the virus to replicate more efficiently in the cooler temperatures of the upper respiratory system. Since current Swine Flu lacks that characteristic, it replicates more efficiently in the lower part of the system, and the intestinal tract. AD's post of experiments on animals infected with the Swine Flu virus bears this out.

The fact that Swine Flu has continued its spread outside of the normal flu season probably has more to do with the fact that it currently has a target rich environment. That is, lots of people out that have no immunity to this novel pathogen. New infections come easily, without respect to the weather.

[HenryN]

Re: Expert warns of misunderstanding behind 1918 flu

That too is the subject of debate. More likely (IMHO) is that the lung pathology due to cytokine storm establishes a good petri dish for the growth of bacteria, and that secondary bacterial infection had nothing to do with the primary cause of death.

Again, we'll only know for certain in retrospect.

I think the data are quite clear. Previously healthy young adults are dying in 2009, even though there are antivirals and antibiotics. Swine H1N1 can kill very quickly and may be too advanced for anti-virals to be effective (even if there is no anti-viral resistance). The rapid test for influenza A is not very sensitive and false negatives are common. Similarly, MRSA has been associated with flu infections, so bacteria can kill, even after treatment with antibiotics (and many patients have died after being sent home with antibiotics).
These 2009 deaths are happening worldwide, including countries like the US, UK, Canada, and Australia in areas where infections have not reached a pandemic level, which would limit care and treatment.

[Mamabird]

Re: Expert warns of misunderstanding behind 1918 flu

I think the data are quite clear. Previously healthy young adults are dying in 2009, even though there are antivirals and antibiotics. Swine H1N1 can kill very quickly and may be too advanced for anti-virals to be effective (even if there is no anti-viral resistance). The rapid test for influenza A is not very sensitive and false negatives are common. Similarly, MRSA has been associated with flu infections, so bacteria can kill, even after treatment with antibiotics (and many patients have died after being sent home with antibiotics).
These 2009 deaths are happening worldwide, including countries like the US, UK, Canada, and Australia in areas where infections have not reached a pandemic level, which would limit care and treatment.

Yes, these types of deaths are happening worldwide, but not yet with significant frequency.

[GennieF]

Re: Expert warns of misunderstanding behind 1918 flu

So, why would the deaths in healthy adults be happening in certain instances and not others? Are there certain "triggers", are their multiple strains, etc.? What are the theories that would cause it to increase in frequency? Judging by the articles I have seen, it looks like the potential is there, but I do not have a background in science so I do not know if these are dumb questions.

[GennieF]

Pandemic wave theory in doubt

Thursday 13 August 2009
Pandemic wave theory in doubt
Experts see weak evidence behind concerns over severe winter wave of influenza

The 2009 pandemic could recede without resurging with a sweeping wave of severe influenza, write David Morens and Jeffery Taubenberger this week in JAMA. Health authorities in Europe and elsewhere have warned that worse may yet to come as more countries get into flu season, but the authors find few signs of distinct ?waves? of illness in large-scale outbreaks over the past two centuries.

?With little consistent evidence of wavelike behaviour in the major influenza epidemics and pandemics of the past, there is a general tendency of pandemics to quickly assume annual seasonality in temperate zones,? say Morens and Taubenberger, of the US National Institutes of Health in Bethesda, Maryland.

It usually takes at least one recurrence before a new flu virus blends into more familiar patterns to circulate seasonally or annually, explain the authors in the commentary. This occurs as viruses change and more people build up immune defences against them. ?The pandemics of 1957 and 1968 generally exhibited no more than 1 (mostly seasonal) recurrence, typically affecting populations not involved in the first pandemic appearance, and quickly became seasonal epidemics.?

Even in the case of the ?Spanish Flu? of 1918?1919, when 20 million people are estimated to have died, there is no evidence to show which viruses were involved in spring-time outbreaks of mild influenza-like illness and a subsequent epidemic of more serious illness. The assumption that a more virulent virus appeared in the winter followed evidence of changes in mortality during the course of that pandemic, not changes in the virus, infectious-disease experts have suggested.

?The first documented wave of 1918, often confusingly referred to as the spring wave, was actually a summer surge of influenza fatalities concentrated in some but not all northern European countries between late June and August 1918,? explain Morens and Taubenberger.

The impression that a spring pandemic wave preceded a later more serious epidemic in 1918 has drawn comparisons with the current situation, because most countries have seen mainly mild cases of illness associated with the novel swine-origin A/H1N1 strain of influenza. This has fuelled speculation that the pandemic might pick up speed later in the year, and that a more virulent virus might evolve.

The authors suggest that fears of a resurgence bringing more serious illness could also be off the mark. Past pandemics have varied in severity as well as where and when they appeared, they point out, adding that evidence of unchanged or lessening severity over time is ?much greater? than the evidence of increased severity.

Experimental studies suggest that a flu virus could get weaker as it spreads through the population, says Heath Kelly, Head of the Epidemiology Unit at the Victorian Infectious Diseases Reference Laboratory and Associate Professor at the University of Melbourne, Australia. ?It would be reasonable to expect an undrifted [unchanged] virus to become less virulent, rather than more virulent, over time, having passed through many hosts.?

Kelly agrees that waves of illness may not be a significant feature of pandemics. In 1918, the ebb and flow of flu cases could have resulted from other factors, he explains, such as relaxed social-distancing measures, changes in age-specific attack rates, or a particular feature of the virus.

There are still many unknowns about the 2009 pandemic, notes Kelly. But the unanswered questions, including how many people are likely to die as flu season approaches in the northern hemisphere, are the same questions that vex health experts dealing with seasonal influenza, he says.

Although the ?global industry? dedicated to keeping track of, controlling, and preventing influenza is important and impressive, it has been built on ?surprisingly shaky foundations?, adds Kelly.

Morens and Taubenberger see hopeful signs in the new H1N1 virus?s modest ability to spread from person to person, its arrival during the summer, and the evidence of some pre-existing immunity in some vaccinated or older people. ?Pandemic history suggests that changes neither in transmissibility nor in pathogenicity are inevitable,? they write. ?It will be critical to assess the effect of large-scale pandemic outbreaks in the Southern Hemisphere in the current and coming (winter) months.?

Evidence from the ongoing pandemic in Australia, published this month in an article co-authored by Kelly, suggests that the 2009 pandemic strain predominated over seasonal strains over the course of 10 weeks, becoming responsible for 95% of all illness cases reported in the country. There was no evidence that people of any age were protected by having received seasonal flu vaccine.

http://www.eht-forum.org/news.html?fileId=news090813121221&from=home&id=0

[AlaskaDenise]

Re: Expert warns of misunderstanding behind 1918 flu

I wish when writers compose these types of articles they would not refer to "experts" collectively, but rather take an idea (like waves) and present the latest thinking from several leading experts. They could write about the different viewpoints of YiGuan:Kawaoka:Taubenberger:Webster.

Then there's this:

The assumption that a more virulent virus appeared in the winter followed evidence of changes in mortality during the course of that pandemic, not changes in the virus, infectious-disease experts have suggested.

The author clearly missed one of Taubenberger's major points - since we only have ONE SAMPLE of complete 1918 virus, we have NO EVIDENCE to prove any particular assumptions about various waves, virulence patterns, etc.

The way that particular sentence is written, it erroneous implies there is evidence that the virus didn't change.

As ARR_309 said: "Absence of evidence is not evidence of absence."

.

[Blue]

Re: Expert warns of misunderstanding behind 1918 flu

Furthermore, I fully believe we will see something like this come this fall with H1N1, at least in terms of cases.

Will it have the same virulence as 1918? I have no idea. However, it is important to remember, most of those that died in 1918 did so because of the secondary bacterial infection (at least that is what some research says).

How do we know that it was bacterial versus viral pneumonia?

[gsgs]

Re: Expert warns of misunderstanding behind 1918 flu

we have the weekly/daily recorded deathrates from influenza from
various cities

how it was introduced, the ships,

clearly 2 waves in 1918 who can deny it

[gsgs]

Re: Expert warns of misunderstanding behind 1918 flu

if it wa the same virus in both waves in 1918, then why
the two types of disease, of virulence in many different
parts of the world ?

[mixin]

Re: Expert warns of misunderstanding behind 1918 flu

Is it possible for someone to post the opposite view from experts so that we all can see the players in this debate? In other words, what experts are taking the position that will see another wave of much greater severity akin to the 1918 experience?

There are a few out of 60 polled who think a higher virulence is likely:

How likely is it that a more virulent strain will emerge? The majority of respondents did not rule it out: two thirds said they thought that higher virulence was "possible". Only a small proportion said it was "likely". Around 30 per cent of respondents believe there is a fifty-fifty chance or greater of increased virulence.

From: Swine flu: How experts are preparing their families

http://www.flutrackers.com/forum/showthread.php?t=120956

[Mamabird]

Re: Expert warns of misunderstanding behind 1918 flu

hat tip Snowy Owl -

"The virus is still around and ready to explode," said William Schaffner, an influenza expert at the Vanderbilt University School of Medicine who advises federal health officials. "We're potentially looking at a very big mess."

I don't know of any expert in the field that would disagree that there is the potential for a big mess.

But is Dr. Schaffner taking a stand that this coming flu season is going to be really ugly? In other words, based on the virus that is circulating today, will it cause more serious illness than Seasonal Flu?

[Jeremy]

Re: Expert warns of misunderstanding behind 1918 flu

I don't know of any expert in the field that would disagree that there is the potential for a big mess.

But is Dr. Schaffner taking a stand that this coming flu season is going to be really ugly? In other words, based on the virus that is circulating today, will it cause more serious illness than Seasonal Flu?

Mamabird,

I tend to find that a virus that kills/incapacitates relatively young and healthy individuals a more serious illness than a virus that attacks the very old/young and those with weakened immune systems.

Doesn't the target age groups and cases we have seen today already qualify it as more serious than Seasonal Flu?