A new look at an old virus:

patterns of mutation

accumulation in the human H1N1

influenza virus

since 1918

Robert W. Carterand John C. Sanford (2012)

1889-

1890

1893 1917-1918 1957 1977 2009

~375

mutations

H1N1

influenza

strain

entered

human

population H1N1

“Russian”

flu

outbreak

Derivatives

of original

virus

circulating

in human

and swine

Human

strain went

extinct

Reappeared in

Anshan, China

Swine

H1N1

Reassortment

between

H1N1 and

H1N2

“We are now moving into the post-

pandemic period. The new H1N1

virus has largely run its course.”

Dr. Margaret Chan

WHO Director-General

10 August 2010

2. Proof of the occurrence of

genetic attenuation

Key Messages

• Process virus changes to

become harmless or less

virulent

• Long term – gradually through

mutation accumulation

Terminology

Terminology

Influenza virus have high mutation rates

Mutations primarily non-adaptive

( high error rate)

Accumulation of

deleterious mutations

What causes REDUCTION in

mortality rate???

Herd immunity ??

Advances in

medicine & hygiene

??

Natural attenuation of

H1N1 viruses ??

Advances of medicine and hygiene??

Reduction of

mortality rate

and stage of

medical advance

or hygiene

advance is not

synchronic.

Improved herd immunity??

Not sufficient to explain the

continuous decline of H1N1 related

mortality rate over multiple human

generation.

Natural attenuation of H1N1

viruses ??

Found strong correlation

between time, mutation count

and reduced death rate of

influenza H1N1.

Long term historical

evidence and theoretical

studies using numerical

simulation strongly support

the concept of natural

genetic attenuation of

RNA viruses.

How does genetic

attenuation occur?

Due to

accumulation

of deleterious

mutation.

Does Mutations

Accumulation Occurs?

Proof of occurrence of

genetic attenuation of H1N1

human lineage?

Almost all human H1N1 influenza lineages rapidly

go extinct.

H1N1 genome is found to be systemically

degenerating since 1918.

Consistent loss of codon specificity overtime

within human H1N1 lineage.

Extinction of human H1N1 lineage both in

1950s and 2009.

H1N1: Extinct? Or still circulating?

“We show compelling new evidence

supporting the extinction of human H1N1 in the 1950s, ……, and an apparent second

extinction event of the human H1N1 lineage in 2009.”

According to author:

REALLY…….?

BUT…

the officials said..

Can virus be…..predictable?

Using the large

body of data from database

OBSERVE

Trend of virus strain in different aspect

Prediction

of possible

behaviour of virus

strains

Can this be the future of

pandemic management?

Scientist giving

nature a helping

hand ?

Now they are DEADLY!

WE HAD FUN ANALYSING! DID YOU?