Renowned Scientist: Bird Flu will kill 50% of humanity

[Divinus Arma]

Good Points, both of you. I assumed as much. My concern is that our medical facilities would be stretched beyond the breaking point.

World Health Organization Tidbits:

During past pandemics, attack rates reached 25-35% of the total population. Under the best circumstances, assuming that the new virus causes mild disease, the world could still experience an estimated 2 million to 7.4 million deaths (projected from data obtained during the 1957 pandemic). Projections for a more virulent virus are much higher. The 1918 pandemic, which was exceptional, killed at least 40 million people.

Pandemics can cause large surges in the numbers of people requiring or seeking medical or hospital treatment, temporarily overwhelming health services. High rates of worker absenteeism can also interrupt other essential services, such as law enforcement, transportation, and communications. Because populations will be fully susceptible to an H5N1-like virus, rates of illness could peak fairly rapidly within a given community. This means that local social and economic disruptions may be temporary. They may, however, be amplified in today’s closely interrelated and interdependent systems of trade and commerce. Based on past experience, a second wave of global spread should be anticipated within a year.

Is the world adequately prepared?
No. Despite an advance warning that has lasted almost two years, the world is ill-prepared to defend itself during a pandemic. WHO has urged all countries to develop preparedness plans, but only around 40 have done so.

What about the pandemic risk?
A pandemic can start when three conditions have been met: a new influenza virus subtype emerges; it infects humans, causing serious illness; and it spreads easily and sustainably among humans. The H5N1 virus amply meets the first two conditions: it is a new virus for humans (H5N1 viruses have never circulated widely among people), and it has infected more than 100 humans, killing over half of them. No one will have immunity should an H5N1-like pandemic virus emerge.
All prerequisites for the start of a pandemic have therefore been met save one: the establishment of efficient and sustained human-to-human transmission of the virus. The risk that the H5N1 virus will acquire this ability will persist as long as opportunities for human infections occur. These opportunities, in turn, will persist as long as the virus continues to circulate in birds, and this situation could endure for some years to come.

[Papewaio]

Does a virus keep the same severity of illness as it mutates to allow a different vector of dispersion?

[Divinus Arma]

Does a virus keep the same severity of illness as it mutates to allow a different vector of dispersion?

I believe that is the very problem that scientists are most concerned about.

Interestingly enough,

Scientists: 1918 Killer Spanish Flu Was a Bird Flu

Scientists who re-created the 1918 Spanish flu say the killer virus was initially a bird flu that learned to infect people. Alarmingly, they find that today's H5N1 bird flu is starting to learn the same tricks.

"These H5N1 viruses are being exposed to human adaptive pressures, and may be going down a similar path to the one that led to the 1918 virus," Taubenberger said in a news conference. "But the H5N1 strains have only a few of these mutations, whereas the 1918 virus has a larger number."

The good news is that the H5N1 flu bug still has a long way to go. The 1918 bug seemed to need several changes in every one of its eight genes. The H5N1 virus is making similar changes but isn't very far along.

"So, for example, in the nuclear protein gene we speculate there are six genes crucial [for human adaptation]," Taubenberger says. "Of those six, three are present in one or another H5N1 strain. But usually there is only one of these changes per virus isolate. That is true of other genes as well. You see four, five, or six changes per gene in the 1918 virus, whereas H5N1 viruses only have one change or so. It shows they are subjected to similar [evolutionary] pressures, but the H5 viruses are early on in this process."

The avian virus adopts its genes from contact with a human virus. The genes "switch" and both apparently mutate.

What is not clear from my readings is what specific genetic material is retained in the swap.

The severity of the symptoms are a product of the virions capability to infect; the more facilitating a virion's genes are towards this end, the more cells that are infected, and ultimately, the greatest the symptoms will be.

The major issue with this mutation is the capability of H5N1 to infect and consequently destory cells; couple that destructive ability with adaptability to a new host and we have the pandemic. We lack the ability to combat it and it is extermely destructive.

IIRC, the human casualties have largerly been a product of deep lung tissue damage. This is unusual in typical influenza.