Electron micrograph of H5N1 influenza virus particles.
The report appearing in yesterday's Milwaukee Journal -Sentinel was brief but had the impact of a blow to the solar plexus. Word, for word, it reported:
"Genetic analysis of the H5 N1 avian flu virus responsible for at least nine human deaths in China portrays a virus evolving to adapt to human cells, raising concern about its potential to spark a new global flu pandemic.
The collaborative study, conducted by a group led by Masato Tashiro of the Influenza Virus Research Center, National Institute of Infectious Diseases, and Yoshihiro Kawaoka of the University of Wisconsin-Madison and the University of Tokyo, appears in the current edition of the journal Eurosurveillance. The group examined the genetic sequences of H7N9 isolates from four of the pathogen's human victims as well as samples derived from birds and the environs of a Shanghai market.
"The human isolates, but not the avian and environmental ones, have a protein mutation that allows for efficient growth in human cells and that also allows them to grow at a temperature that corresponds to the upper respiratory tract of humans, which is lower than you find in birds," Kawaoka, a leading expert on avian influenza, said in a news release from UW-Madison.
The findings, drawn from genetic sequences deposited by Chinese researchers into an international database, provide some of the first molecular clues about a worrisome new strain of bird flu, the first human cases of which were reported on March 31 by the Chinese Center
The preceding ought to be enough to get any normal human's nerves on edge. Also, if unleashed in an outbreak against an essentially 'naked" (from immunity) populace, the results would be devastating. In 2003, world-renowned virologist Robert G. Webster published an article titled: "The world is teetering on the edge of a pandemic that could kill a large fraction of the human population" in American Scientist. He called for adequate resources to fight what he sees as a major world threat to possibly billions of lives.
On September 29, 2005, David Nabarro, the newly appointed Senior United Nations System Coordinator for Avian and Human Influenza, warned the world that an outbreak of avian influenza could kill anywhere between 5 million and 150 million people. The reported mortality rate of highly pathogenic H5N1 avian influenza in a human is high; WHO data indicate 60% of cases classified as H5N1 resulted in death.
My take, given the H5N1 would (from cases analyzed thus far) incept a "cytokine storm" - similar to what the H1N1 Spanish Flu did, is that at least 500 million would perish, and possibly as many as 1 billion. I believe the reason the CDC is now barely a step from emergency mode (their website info now is partially 'redded out' with reference to old info and the emphasis is now on 'real time information) is because they are fully aware of the fact the Avian flu in its H5N1 human-to human manifestation could wipe out up to one seventh of the global populace.
Richard Besser, former CDC doc and now medical correspondent with ABC News, sounded downright nervous in his report last night from China, talking about a "race against the clock".
Back to the phenomenon of the cytokine storm: Research on genetically restored Spanish flu discloses that death likely arrived via a cytokine storm. In the current Avian flu cases, one boy documented with H5N1 experienced diarrhea followed rapidly by a coma without developing respiratory or flu-like symptom. This shows that one can perish that suddenly, and with no evident breathing problems. There have been studies of the levels of cytokines in humans infected by the H5N1 flu virus. Of particular concern is elevated levels of tumor necrosis factor-alpha, a protein associated with tissue destruction at sites of infection and increased production of other cytokines. Flu virus-induced increases in the level of cytokines is also associated with flu symptoms, including fever, chills, vomiting and headache.
The inflammatory cascade triggered by H5N1 has been called a 'cytokine storm' by some, because of what seems to be a positive feedback process of damage to the body resulting from immune system stimulation. H5N1 induces higher levels of cytokines than the more common flu virus types
The latest CDC Notice is given as follows:
The highly pathogenic avian influenza A (H5N1) epizootic (animal outbreak) in Asia, Europe, the Near East, and Africa is not expected to diminish significantly in the short term. It is likely that H5N1 virus infections among domestic poultry have become endemic in certain areas and that sporadic human infections resulting from direct contact with infected poultry and/or wild birds will continue to occur. So far, the spread of H5N1 virus from person-to-person has been very rare, limited and unsustained. However, this epizootic continues to pose an important public health threat.
There is little pre-existing natural immunity to H5N1 virus infection in the human population. If H5N1 viruses gain the ability for efficient and sustained transmission among humans, an influenza pandemic could result, with potentially high rates of illness and death worldwide. No evidence for genetic reassortment between human and avian influenza A virus genes has been found to date, and there is no evidence of any significant changes to circulating H5N1 virus strains to suggest greater transmissibility to or among humans.
Genetic sequencing of avian influenza A (H5N1) viruses from human cases in Vietnam, Thailand, and Indonesia shows resistance to the antiviral medications amantadine and rimantadine, two of the medications commonly used for treatment of influenza. This leaves two remaining antiviral medications (oseltamivir and zanamivir) that should still be effective against currently circulating strains of H5N1 viruses. A small number of oseltamivir resistant H5N1 virus infections of humans have been reported. Efforts to produce pre-pandemic vaccine candidates for humans that would be effective against avian influenza A (H5N1) viruses are ongoing. However, no H5N1 vaccines are currently available for human use.
Research suggests that currently circulating strains of H5N1 viruses are becoming more capable of causing disease (pathogenic) in animals than were earlier H5N1 viruses. One study found that ducks infected with H5N1 virus are now shedding more virus for longer periods without showing symptoms of illness. This finding has implications for the role of ducks in transmitting disease to other birds and possibly to humans as well. Additionally, other findings have documented H5N1 virus infection among pigs in China and Vietnam; H5N1 virus infection of cats (experimental infection of housecats in the Netherlands, isolation of H5N1 virus from domestic cats in Germany and Thailand, and detection of H5N1 viral RNA in domestic cats in Iraq and Austria); H5N1 virus infection of dogs (isolation of H5N1 virus from a domestic dog in Thailand); and isolation of H5N1 viruses from tigers and leopards at zoos in Thailand). In addition, H5N1 virus infection in a wild stone marten (a weasel-like mammal) was reported in Germany and in a wild civet cat in Vietnam Asia in 2003 continue to evolve and may adapt so that other mammals may be susceptible to it as well.
Highly pathogenic H5N1 in people can include:
Symptoms:
• Fever and cough
• Acute respiratory distress
• Shortness of breath/difficulty breathing
• Abdominal pain
• Diarrhea
Complications:
• Pneumonia
• Respiratory failure
• Shock
* Altered mental state
• Seizures
• Failure of multiple organs (e.g. kidney failure)
• Death
The other bit of news (from flu.gov) is that
People need to also grasp that even if an initial vaccine is successful, such virulent influenza outbreaks often come in waves. In the case of the Spanish flu there was a first relatively mild wave, then a much more deadly form (that incepted more cytokine storms). The flu virus also mutates so that a vaccine that may work for the initial H5N1 onslaught may not work for a later one. For a fairly good depiction of what could transpire, see the movie: 'Fatal Contact: Bird Flu in America'. We are talking of so many dead that corpses have to be collected daily in the streets by garbage trucks, driven to landfills, stacked like cordwood and buried or set afire. We're also talking of massive dislocation of supply lines, supermarket shelves bare, and even the possibility of water, electricity output affected. As for hospitals....the floods of patients in every city and town will overwhelm them and their resources within days!
Having seen what my own wife suffered - barely able to breathe at times- with the H3N2 flu last December (written about in my Dec. 25 blog post) I don't want to see anything any worse! We may need to pare down the world's burgeoning populace- but not this way!
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