Bird Flu 2006: Mutation

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A virulently fatal form of H5N1 bird flu has not yet appeared in humans. But "flu season" runs from fall through early winter in the northern hemisphere - so this is the time when new mutations are most likely to appear. Scientists are afraid that H5N1 bird flu will infect someone already sick with another virus, cross-breed inside the host, and mutate into a form that is easily transmitted human-to-human. A virulent strain will most likely occur if H5N1 cross-breeds with another flu strain. Authorities are on high alert.

Scientists know that diseases use human bodies as mixing vessels - microbes cross-breed and mutate when a victim has more than one disease. This is why virulent new diseases tend to appear in over-crowded places without adequate medical care. It's a matter of opportunity.

H5N1 bird flu is a 'new' mutation, different from seasonal flu - as was the 1918 bird flu. Seasonal flu tends to kill only the very young and very old. But unlike seasonal flu, and like the 1918 bird flu, H5N1 is most deadly in young people roughly between 7 and 40 years of age.

The US government just released a report explaining one way this can happen. In an animal study, scientists infected a group of mice with a mild virus: the virus killed 0% of the younger mice, and 14% of the older mice. The researchers then extracted the virus from the older infected survivors, and used it to infect a new group. They found that in its new form (after cycling through a host), the virus killed 43% of younger mice and 71% of older mice.

The originally mild virus, or "low pathogenic" form, gained virulence after passing through the host(s), to become a "high pathogenic" strain.

U.S. Researchers Discovering What Makes Flu Viruses Lethal

In an animal study, none of a group of younger adult mice infected with a mild strain of a common virus died, but 14 percent of older infected mice did. The scientists then isolated and studied the mild virus from the infected older mice.

The mild viral strain did not affect young adult mice in previous tests, but the scientists found that after it had cycled through an older mouse host, it killed 43 percent of other younger mice later infected and 71 percent of other older mice later infected.

The scientists do not know how the viral strain mutated to mimic its virulent cousin in the older mouse hosts, but concluded that because of the world’s increasingly older population, the potential impact of age-associated viral evolution on public health warrants further investigation.

NOTE: A bird flu is considered "high path" only if it kills 76% to 100% of chickens infected artificially (ie., 7 or 8 out of 8 infected).

And FYI: Low-pathogenic H5N1 has been confirmed in the United States this year - including in Michigan, Pennsylvania and Maryland.

Also NOTE:

* In the USA, the Departments of Agriculture and Interior tests and reports on H5N1 bird flu only in wild birds;

* The government does not require US poultry producers to test for H5N1 bird flu; and

* Testing food chickens for H5N1 bird flu is totally voluntary in the USA.

A bit of an oversight considering how mutation works, dontcha think?





This is the first in a series of 9 new bird flu threads about Mutation; Water Safety; Food Safety; Symptoms; Diagnosis; Medical Treatments; Traditional, Alternative, and Over-the-Counter Treatments; Molecular Pathology; and Spread.

An important follow-up to this thread with more info:

Beyond Bird Flu: The Perfect Microbial Storm

It's rather alarming to see the sudden rush and burst of news relating to preparations for a pandemic. It's closer than many of us would like to think.

Africa: U.S. Warns On Bird Flu

Survivors Recall Horror of Flu Pandemic

Rhode Island making preparations for pandemic flu

Washington area officials prepare for possibility of flu pandemic

Missouri State, local health departments ready for possible flu outbreak.

Texas prepares for possible pandemic flu outbreak

NJ only partly prepared for expected flu pandemic

The H5N1 bird flu virus is changing and becoming less lethal. BUT - the less lethal the virus, the more dangerous it becomes.

Bird Flu Panic Waning: Sense of Urgency Rising

The bird flu virus is still killing, still spreading, and still mutating. In recent weeks, it's reappeared in Korea and flared in Somalia, Cote d'Ivoire, Ukraine and Russia. The death toll among birds, both those infected and those killed to avoid the spread of the disease, exceeds half a billion. Deaths among humans are at 154, with nearly half of those occurring this year.

It's not just complacency that worries Kasai. The virus is changing. ...When bird flu first started killing people, about 80 percent of those infected died. The lethality has dropped to about 60 percent. Cases reported outside of Indonesia have a better than 50 percent chance of survival.

Normally, that's good news. But bird flu needs a living host to undergo the genetic mutations that can spread it from one person to the next. So the less lethal the virus, paradoxically, the more dangerous it becomes.

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[edit on 26-12-2006 by soficrow]

How do microbes mutate?

It all starts with the proteins.

For example:

Medications that target proteins cause the targeted proteins to misfold, and create new protein strains called prions. (Most do.) Then the prions interfere with the microbe's gene expression, and change its DNA.

Vaccines also force viruses to change direction, and mutate along new pathways. Unfortunately.

There is no guarantee that the M2 protein will not mutate in the future - meaning the jab will have to be regularly reformulated cautions Dr Ron Cutler, an infectious diseases expert from the University of East London - about the new "universal" flu vaccine in the works.

Equally interesting:

Depending on the protein, the prion also can infect other organisms' proteins and cells directly - even human ones. Then its a whole new mutation-and-evolution ballgame.




[edit on 1-1-2007 by soficrow]