The H1N1 flu, sometimes called swine flu, is a type of influenza A virus. During the 2009-10 flu season, a new H1N1 virus began causing illness in humans. It was often called swine flu and was a new combination of influenza viruses that infect pigs, birds and humans. The World Health Organization (WHO) declared the H1N1 flu to be a pandemic in 2009. That year the virus caused an estimated 284,400 deaths worldwide. In August 2010, WHO declared the pandemic over. But the H1N1 flu strain from the pandemic became one of the strains that cause seasonal flu.

1. Swine
Flu
Virus
Ahmad Thanin

2. Definition
Swine influenza (swine flu) is a
respiratory disease in pigs
caused by type A influenza
viruses that regularly cause
outbreaks of influenza in pigs.
When an influenza virus that
normally circulates in swine (but
not people) is detected in a
person, it is called a “variant
influenza virus.”
• For example, if a swine origin influenza
A H3N2 virus is detected in a person,
that virus will be called an “H3N2
variant” virus or “H3N2v” virus.

3. Virus Types and
Variants
The main swine
influenza viruses
circulating in U.S.
pigs in recent years
have been:
Swine
triple
reassortant
(tr) H1N1
influenza
virus
trH3N2
virus
trH1N2
virus

4. Flu Strains and Transmission
ANTIGENIC
SHIFT
Influenza viruses that infect
pigs may be different from
human influenza viruses.
Because pigs are susceptible to
avian, human and swine influenza
viruses, they potentially may be
infected with influenza viruses
from different species (e.g., ducks
and humans) at the same time.
If this happens, it is possible
for the genes of these viruses
to mix and create a new virus.
This type of major change in
the influenza A viruses is
known as antigenic shift.
If this new virus causes
illness in people and can be
transmitted easily from person-
to-person, an influenza
pandemic can occur.
This is what happened in 2009 when
an influenza A H1N1 virus with
swine, avian and human genes
emerged in the spring of 2009 and
caused the first pandemic in more
than 40 years.

5. Flu Strains and Transmission
INFECTION Swine flu viruses do not
normally infect humans,
however, sporadic human
infections with influenza
viruses that normally infect
swine have occurred.
As discussed, when
this happens, these
viruses are called
“variant viruses.”
Most commonly, human infections
with variant viruses have
occurred in people exposed to
infected pigs (e.g., children
near pigs at a fair or workers
in the swine industry).
In addition, there have been
documented cases of multiple
persons becoming sick after
exposure to one or more sick
pigs.
Also, cases of limited
person-to-person
spread of variant
viruses have occurred.

6. Flu Strains and Transmission
TRANSMISSION
Human-to-human
transmission of
variant flu viruses
has occurred, though
this method of spread
has been limited.
This kind of transmission
is thought to occur in the
same way that seasonal flu
transmits in people, which
is mainly through coughing
or sneezing by people who
are infected.
People may also
become infected by
touching something
with flu viruses on
it and then touching
their mouth or nose.
It’s important to note
that in most cases,
variant flu viruses have
not shown the ability to
spread easily and
sustainably from person to
person.

8. SPREAD
Spread of
flu viruses
between pigs
and people
is thought
to occur in
one of three
ways:
•The main way is when an infected pig
(or person) coughs or sneezes, and
droplets containing virus spread
through the air.
•There is also evidence that variant
flu viruses can spread by touching
something that has virus on it and
then touching the eyes, nose or
mouth.
•A third way to possibly get
infected, is to inhale small
particles in the air that contain
variant flu virus.

9. Swine Flu Symptoms
– Human
Fever.
Lethargy
lack of appetite and coughing.
Some people have also reported runny nose, sore
throat, eye irritation, nausea, vomiting and
diarrhea.
In severe cases, pneumonia may develop, and death
may occur.

10. Swine Flu Symptoms – PIGS
Swine flu viruses
can cause high
levels of illness in
swine herds, but
usually cause few
deaths.
Common signs in
sick pigs
include
• Fever
• coughing (barking)
• discharge from the
nose or eyes,
• Sneezing
• breathing
difficulties
• eye redness or
inflammation
• going off feed.

11. Influenza or Common Cold?
DIFFERENCES
The main difference is that the symptoms of influenza come
on rapidly and are typically accompanied by muscle aches
and a fever.
The common cold has a more insidious onset and is
associated with a runny nose, sneezing, and blocked nasal
passages.
An important additional symptom of swine flu is that
diarrhea and vomiting have been quite prominent symptoms
among cases.

12. Influenza or Common
Cold?
DIAGNOSIS
• To diagnose variant
influenza A virus
infection, a
respiratory specimen
would generally need to
be collected within the
first 4 to 5 days of
illness (when an
infected person is most
likely to be shedding
virus).

14. Swine Flu: What to Do
TESTING
If you get sick with a flu-like illness as
described above and have recently visited
an affected area or have been in contact
with a known case of swine flu, contact
your GP/family doctor by telephone.
If you have symptoms of flu:
• Cover your nose and mouth with disposable
tissues when sneezing, coughing, wiping and
blowing your nose.
• Dispose of used tissues in the nearest waste
bin.

15. Swine Flu: What to
Do
TRAVELLING /
PROTOCOLS
If traveling in an affected country,
there are certain sensible
precautions you can take:
• Wash your hands often with soap and water,
and especially after coughing and sneezing.
• Alcohol-based hand cleaners are also
effective.
• Try to avoid close contact with sick people.
• If you are sick with flu, stay at home to
avoid spreading the infection to others.
Avoid touching your eyes, nose and mouth.

16. HIGH RISK
Most variant flu virus infections have resulted in mild illness in people,
but severe illness, including illness resulting in hospitalization and
death can and has occurred.
Similar to seasonal flu, some people are at high risk of developing serious
illness from variant flu virus infections.
This includes children younger than 5 years old, people 65 years of age and
older, pregnant women, and people with certain underlying health conditions
(like asthma and other lung disease, diabetes, heart disease, weakened
immune systems, and neurological or neurodevelopmental conditions).

17. EXPOSURE
• Most reported variant flu
virus infections in people
have occurred following
exposure to infected pigs
or their virus contaminated
environments, particularly
in association with large
agricultural fairs.
• Many fairs have swine
exhibitions, where pigs
from different farms come
in close contact with each
other and with people.

19. Swine
Flu
Safety
Guide

20. Cause for Concern
PANDEMIC
An influenza pandemic is defined as a new or novel
influenza virus that spreads easily between humans.
• When new influenza viruses are introduced into the environment,
humans don’t have any natural immunity to protect against them.
Therefore, there is a risk that new influenza
viruses could develop into a pandemic if the virus
passes easily from person to person.
• It is too early to say whether recent cases1 (2019) will lead to
a larger outbreak or could represent the appearance of a
potential pandemic strain of influenza.

21. Cause for Concern
2009
• The virus that was found in the human swine influenza cases in the
US and Mexico in 2009, contained pig, bird and human genes in a
combination that had not been observed before anywhere in the world.
Why is this situation of concern?
• the virus spread from person to person, and the resulting illnesses
were severe in a substantial number of cases.
In addition
• the new influenza virus spread rapidly around the world.
• By the time WHO declared a pandemic in June 2009, a total of 74
countries and territories had reported laboratory confirmed
infections.
After early outbreaks in North America in April 2009

22. Cause for Concern
EFFECTS
The 2009 virus led to patterns of death and illness not normally seen
in influenza infections.
•Most of the deaths caused by the pandemic influenza occurred among younger people,
including those who were otherwise healthy.
Pregnant women, younger children and people of any age with certain
chronic lung or other medical conditions appeared to be at higher risk
of more complicated or severe illness.
Many of the severe cases had been due to viral pneumonia, which is
harder to treat than bacterial pneumonias usually associated with
seasonal influenza and many of these patients required intensive care.

23. Cases and
Treatment
REPORTING
In the past
• CDC received reports of
approximately one human
infected with influenza
viruses that are usually
found in swine, every one
to two years.
• However, beginning in
2012, there was a jump in
the number of these case.

24. Cases and Treatment
MEDICATIONS
Is there a vaccine against human swine influenza?
• There is currently no vaccine to protect people from swine
influenza.
• However, it is claimed that the best way to protect against all
forms of flu is to get the seasonal flu vaccine.
Are there medicines to treat human swine influenza?
• Yes, Influenza antiviral drugs can be used to treat influenza
infections, including human infections with influenza viruses
that normally circulate in swine (swine influenza).
• There are four different antiviral drugs that are recommended
for use in the United States: Oseltamivir, Peramivir, Zanamivir,
and Baloxavir.

25. When to
seek
emergency
care:
Fast breathing or
trouble
breathing.
Bluish or grey
skin color.
Not drinking
enough fluids.
Severe or
persistent
vomiting.
Not waking up or
not interacting.
Being so
irritable that
the child does
not want to be
held.
Flu-like symptoms
improve but then
return with fever
and worse cough