MERS has to be tackled more practically ,its nothing to scare unless you find and suspicious case around you.The contributing factors are ,weather ,closed homes ,shisha culture ,and the anatomy of Arabs nostrils play a aggressive role in spread of this new disease.The virus mutated recently in a more more cases in humans appeared in hospitals in Jeddah, which may indicate increased virus transmission from man to man due to mutation in the genome leading to virus adaptation. This event may be associated with loss of some virulence elements in the virus.”to survive, viruses adapt or evolve, changing its surface proteins enough to trick the host cell into allowing it to attach.

1. 1
How viruses mutate???
By Mahboob ali khan
has to be tackled more practically, it’s nothing to scare unless you find and
suspicious case around you. The contributing factors are, weather, closed homes, shisha culture,
and the anatomy of Arabs nostrils play a aggressive role in spread of this new disease in Arabian
Gulf. The virus mutated recently in a more more cases in humans appeared in hospitals in
Jeddah, which may indicate increased virus transmission from man to man due to mutation in the
genome leading to virus adaptation. This event may be associated with loss of some virulence
elements in the virus. “to survive, viruses adapt or evolve, changing its surface proteins enough
to trick the host cell into allowing it to attach.
This ability to mutate from one host to the next, or one species to the next, is one of the traits that
has given the influenza virus a long life and made it both nearly impossible to eradicate and
potentially dangerous to animals and humans alike.
Here we explore the reasons why viruses mutate, how they do it, and what impact their
environment plays in their ability to cause pandemics.
Why do viruses mutate?
To survive: unlike plants, animals and other organisms, the only way a virus can reproduce is
through a host cell, which it does by attaching its surface proteins to the cell's membrane and
injecting its genetic material into the cell. This genetic material, either DNA or RNA, then
carries with it the instructions to the cell's machinery to make more viruses. These new viruses
then leave the cell and spread to other parts of the host organism.
But host organisms are not passive observers to this process, and over time a human's or pig's
immune system can learn from these encounters and develop strategies to prevent reinfection.
The next time the same virus comes to a host cell, it may find that it is no longer able to attach to
the cell's surface membrane. So to survive, viruses must adapt or evolve, changing its surface
proteins enough to trick the host cell into allowing it to attach.
What makes one virus mutate quickly while others change more slowly?
The genetic material inside the virus plays an enormous role in how quickly a virus mutates,
which in turn can impact how the illness can spread in the population.
Viruses that replicate through DNA use the same mechanisms the host cell uses to create its own
DNA, a process that includes a kind of "proof-reading" of the genetic material being copied. This
means mutations occur more slowly.
Examples of DNA viruses such as smallpox. These viruses spread through human populations
and were often fatal. But once vaccinations were developed viruses like smallpox were contained
and all but eradicated. RNA viruses, on the other hand, replicate without a similar proofreading
activity, and as a result, errors in the genetic coding occur. Its these errors that allow RNA

2. 2
viruses, such as influenza and HIV, to mutate rapidly from host cell to host cell, and make it
difficult for vaccines and natural immunities to keep up and prepare for new strains of the virus.
How does a virus travel from an animal like a pig to a human?
Viruses spread from one animal to another through close contact, in whatever manner it normally
spreads, such as coughing or sneezing in the case of a respiratory virus. Normally, these
infections have no impact on the new host since they were not built to infect them. But when one
host is infected by two or more strains of a virus like influenza, new combinations can result.
Influenza, for example, has eight distinct segments to its genome, increasing its ability to form
new combinations that can include elements of avian flu, swine flu and human flu. It's these
recombined versions of the flu that have the potential to cross over and actually spread through a
new host.
Pigs are a particularly good incubator as they have receptors for influenza from all three species,
David Waltner-Toews, author of The Chickens Fight Back: Pandemic Panics and Deadly
Diseases that Jump from Animals to People.
"So, if they happen to be around people or birds that have influenza, they will pick them up, and
the viruses will mix up inside them."
And as the flu spreads, its list of available hosts spreads as well. Until five years ago, for
example, dogs were not susceptible to influenza, But the flu has since spread to canines through
horses.
What role does the environment play in mutation?
One of the big factors in the mutation rate of viruses is population density, said Brown.
"When you have high density conditions and overcrowding, like you would see in a pig farm,
then the mutation occurs much more quickly as it passes from one snout to the next," he said.
The kind of virus likely to thrive is also a function of its environment, he said.
A virus that quickly kills its host as it spreads is more likely to thrive in densely populated areas
where it can out-compete other viruses, but would die out when the supply of new hosts is in
short supply, he said. Conversely, a virus that incubates in the host for weeks and spreads slowly
is more likely to thrive in animals like migratory birds, he said.
How much do farming practices contribute?
Human populations have grown over the past few centuries, and in recent decades, the demand
for pork and chicken has soared. That has led to the proliferation of large, dense farms with
thousands of animals, so those result in a number of factors that boost transmission of viruses
such as influenza:

3. 3
 Many genetically similar animals are kept in one place, and their similarity leaves them
susceptible to the same diseases.
 The stress of crowded conditions increases the chance that infected animals will show
disease symptoms that help the disease spread, such as coughing and sneezing.
 The animals are shipped all over the world.
 People are traveling all over the world, including migrant farm workers brought in from
other countries as cheap agricultural labour.
I think two changes would reduce the spread of new strains of influenza:
 Having larger number of smaller farms instead of a small number of large farms.
 Reducing the reliance of agriculture on global trade.
I saw more cases in humans appeared in hospitals in Jeddah, which may indicate increased virus
transmission from man to man due to mutation in the genome leading to virus adaptation. This
event may be associated with loss of some virulence elements in the virus.”
Fooling the coronavirus proofreading machinery
The polymerase of RNA viruses lacks the proofreading capacity found in the polymerase of
DNA viruses, leading to high error rates and low replicative fidelity. Although the high mutation
rate of RNA viruses enables them to readily adapt to environmental changes, they also risk
'lethal mutagenesis' when accumulating mutations corrupt essential functions.
Bird flu vs. swine flu
Almost all human diseases originate from other animals and then adapt to human hosts- Chickens Fight
Back: Pandemic Panics and Deadly Diseases that Jump from Animals to People.
With influenza, different strains of the virus affect people, birds and pigs. Naturally, human influenza is
the easiest for humans to get and to transmit to other humans. Humans can also get bird influenza and pig
influenza, but it typically requires very close contact with the animals.
Bird or avian influenza is particularly hard to get, but humans who do get it experience very severe
symptoms. That is why people were worried about a deadly pandemic if avian influenza were to mutate in
such a way as to become easily transmissible between humans. Swine influenza is somewhat easier to
transmit to humans but its symptoms tend to be milder than bird influenza.
Most flus contracted by humans are made up of predominately human influenza, but contain
small pieces of avian or swine influenza. Swine flu is unusual because it is made up mostly of
swine influenza but contains small amounts of avian and human influenza.
The movement of a virus between species opens up more opportunities for mutations in the
virus, The mutations would not necessarily make the virus cause more severe disease, but it
cannot be ruled out. Mutations could also perhaps make the virus stronger at beating the immune
system or resistant to drugs.