Swine flu is a
respiratory disease, caused by influenza type A which infects pigs..
There are many
types, and the infection is constantly changing.
Until now it has
not normally infected humans, but the latest form clearly does, and can be
spread from person to person - probably through coughing and sneezing.
What
is new about this type of swine flu?
The World Health
Organization has confirmed that at least some of the human cases are a
never-before- seen version of the H1N1 strain of influenza type A.
H1N1 is the same
strain which causes seasonal outbreaks of flu in humans on a regular basis.
But this latest
version of H1N1 is different: it contains genetic material that is
typically found in strains of the virus that affect humans, birds and
swine.
Flu viruses have
the ability to swap genetic components with each other, and it seems likely
that the new version of H1N1 resulted from a mixing of different versions
of the virus, which may usually affect different species, in the same
animal host.
Pigs provide an
excellent 'melting pot' for these viruses to mix and match with each other.
Symptoms of
swine flu in humans appear to be similar to those produced by standard,
seasonal flu.
These include
fever, cough, sore throat, body aches, chills and fatigue.
Most cases so
far reported around the world appear to be mild, but in
Mexico
lives have been lost.
How
worried should people be?
When any new
strain of flu emerges that acquires the ability to pass from person to
person, it is monitored very closely in case it has the potential to spark
a global epidemic, or pandemic.
The World Health
Organization has warned that taken together the Mexican and US cases could
potentially trigger a global pandemic, and stress that the situation is
serious.
However, experts
say it is still too early to accurately assess the situation fully.
Currently, they
say the world is closer to a flu pandemic than at any point since 1968 -
upgrading the threat from three to four on a six-point scale following an
emergency meeting on Monday.
Nobody knows the
full potential impact of a pandemic, but experts have warned that it could
cost millions of lives worldwide. The Spanish flu pandemic, which began in
1918, and was also caused by an H1N1 strain, killed millions of people.
The fact that
all the cases in the US
and elsewhere have so far produced mild symptoms is encouraging. It
suggests that the severity of the Mexican outbreak may be due to an unusual
geographically- specific factor - possibly a second unrelated virus
circulating in the community - which would be unlikely to come into play in
the rest of the world.
Alternatively,
people infected in Mexico
may have sought treatment at a much later stage than those in other
countries.
It may also be
the case that the form of the virus circulating in
Mexico is
subtly different to that elsewhere - although that will only be confirmed
by laboratory analysis.
There is also
hope that, as humans are often exposed to forms of H1N1 through seasonal
flu, our immune systems may have something of a head start in fighting
infection.
However, the
fact that many of the victims are young does point to something unusual.
Normal, seasonal flu tends to affect the elderly disproportionately.
Can
the virus be contained?
The virus
appears already to have started to spread around the world, and most
experts believe that containment of the virus in the era of readily
available air travel will be extremely difficult.
The
US
authorities say that two drugs commonly used to treat flu, Tamiflu and
Relenza, seem to be effective at treating cases that have occurred there so
far. However, the drugs must be administered at an early stage to be
effective.
Use of these
drugs may also make it less likely that infected people will pass the virus
on to others.
The UK
Government already has a stockpile of Tamiflu, ordered as a precaution
against a pandemic.
It is unclear
how effective currently available flu vaccines would be at offering
protection against the new strain, as it is genetically distinct from other
flu strains.
US scientists are already developing a
bespoke new vaccine, but it may take some time to perfect it, and
manufacture enough supplies to meet what could be huge demand.
A vaccine was
used to protect humans from a version of swine flu in the
US in 1976.
However, it
caused serious side effects, including an estimated 500 cases of
Guillain-Barré syndrome. There were more deaths from the vaccine than the
outbreak.
What
should I do to stay safe?
Anyone with
flu-like symptoms who might have been in contact with the swine virus -
such as those living or travelling in the areas of
Mexico that
have been affected - should seek medical advice.
But patients are
being asked not to go into GP surgeries in order to minimise the risk of
spreading the disease to others. Instead, they should stay at home and call
their healthcare provider for advice.
After the WHO
raised its alert level over swine flu, the Foreign and Commonwealth Office
began advising against all but essential travel to
Mexico .
What
measures can I take to prevent infection?
Avoid close
contact with people who appear unwell and who have fever and cough.
General infection
control practices and good hygiene can help to reduce transmission of all
viruses, including the human swine influenza. This includes covering your
nose and mouth when coughing or sneezing, using a tissue when possible and
disposing of it promptly.
It is also
important to wash your hands frequently with soap and water to reduce the
spread of the virus from your hands to face or to other people and cleaning
hard surfaces like door handles frequently using a normal cleaning product.
If caring for someone
with a flu-like illness, a mask can be worn to cover the nose and mouth to
reduce the risk of transmission. The
UK is looking at increasing its
stockpile of masks for healthcare workers for this reason.
But experts say
there is no scientific evidence to support more general wearing of masks to
guard against infections.
Is
it safe to eat pig meat?
Yes. There is no
evidence that swine flu can be transmitted through eating meat from
infected animals.
However, it is
essential to cook meat properly. A temperature of 70C (158F) would be sure
to kill the virus.
The strain of
bird flu which has caused scores of human deaths in South
East Asia in recent years is a different strain to that
responsible for the current outbreak of swine flu.
The latest form
of swine flu is a new type of the H1N1 strain, while bird, or avian flu, is
H5N1.
Experts fear
H5N1 hold the potential to trigger a pandemic because of its ability to
mutate rapidly.
However, up
until now it has remained very much a disease of birds.
Those humans who
have been infected have, without exception, worked closely with birds, and
cases of human-to-human transmission are extremely rare - there is no
suggestion that H5N1 has gained the ability to pass easily from person to
person.
Where
can I get further advice?
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