Swine influenza, also known as swine flu, is caused by type A influenza viruses that typically infect pigs. The 2009 H1N1 virus was a new strain that was able to infect humans and spread from person to person. Swine flu in humans causes similar symptoms as seasonal flu, including fever, cough and sore throat. While the virus is now considered a seasonal flu virus, there is no vaccine specifically for it. Good hand hygiene and practicing droplet precautions are recommended to limit its spread.
2. What is Swine Influenza
(Swine flu)?
• H1N1 - originally referred to as Swine Flu
• Swine Influenza is typically a respiratory
disease of pigs
• Swine flu has expanded to human-to-human
transmission
• Swine flu is a type of:
– Influenza-Like Illness (ILI)
3. Influenza Virus
Types A and B
Type A
(Seasonal, avian, swine
influenza,….)
Type B
(Seasonal influenza)
Can cause significant disease
Generally causes milder
disease but may also cause
severe disease
Infects humans and other
species (e.g., birds; H5N1)
Limited to humans
Can cause epidemics and
pandemics (worldwide epidemics)
Generally causes milder
epidemics
3
4. Seasonal Influenza
– A public health problem
each year
– Usually some immunity
built up from previous
exposures to the same
subtype
– Infants and elderly most
at risk
Influenza Pandemics
– Appear in the human
population rarely and
unpredictably
– Human population lacks
any immunity
– All age groups, including
healthy young adults
Seasonal Epidemics vs. Pandemics
5. The new virus must beThe new virus must be efficientlyefficiently
transmitted from one human to anothertransmitted from one human to another
The new virus must beThe new virus must be efficientlyefficiently
transmitted from one human to anothertransmitted from one human to another
Prerequisites for pandemic influenza
A new influenza virus emerges to which the
general population has little/no immunity
The new virus must be able to replicate in
humans and cause disease
7. A H1N1 :new virus
• The 2009 H1N1 virus is a hybrid of swine, avian and human strains
Influenza A (H1N1)
• The H1N1 flu virus caused a world-wide pandemic in 2009. It is now a
human seasonal flu virus that also circulates in pigs.
• While the H1N1 viruses have continued to circulate since the pandemic,
2014 is the first season since 2009 that H1N1 has been so predominant in
the United States.
• Getting the flu vaccine is your best protection against H1N1.
• You cannot get H1N1 from properly handled and cooked pork or pork
products.
• Symptoms of H1N1 are similar to seasonal flu symptoms.
8. What is H1N1 flu?
• H1N1 is a flu virus. When it was first detected
in 2009, it was called “swine flu” because the
virus was similar to those found in pigs.
• The H1N1 virus is currently a seasonal flu virus
found in humans.
• Although it also circulates in pigs, you cannot
get it by eating properly handled and cooked
pork or pork products.
9. What is the current Status?
• Centers for Disease Control (CDC) has confirmed
seven (7) cases of Swine Influenza caused by swine
influenza (H1N1) viruses
• Viruses contain a unique combination of gene
segments that have not been reported previously
among swine or human influenza viruses in United
States
10. Signs and Symptoms
Human Influenza
Type of infection Upper and lower respiratory
Fever Yes
Headache Yes
Cough Yes
Respiratory symptoms Varies; sore throat to difficulty
breathing
Gastrointestinal
symptoms
Uncommon, except children,
elderly
Recovery 2-7 days
12. Pathogenesis of influenza in humans
•When influenza virus is introduced into the respiratory tract, by aerosol or
by contact with saliva or other respiratory secretions from an infected
individual, it attaches to and replicates in epithelial cells.
•The virus replicates in cells of both the upper and lower respiratory tract.
•
•Viral replication combined with the immune response to infection lead to
destruction and loss of cells lining the respiratory tract.
•As infection subsides, the epithelium is regenerated, a process that can take
up to a month.
•Cough and weakness may persist for up to 2 weeks after infection.
13. Where is the Incidence Swine Flu?
• According to the CDC as
of April 27, 2009
documented human-to-
human transmission of
swine flu have now
occurred in:
– California
– Texas
– Ohio
– New York
– Mexico
– Eastern Canada
– New Zealand
15. What are the symptoms of swine flu in
humans?
• The symptoms of swine flu in people are expected to
be similar to the symptoms of regular human
seasonal influenza & include:
– fever (greater than 100.0º F or 37.8 º C), AND
– cough & sore throat
– lack of appetite
• Internationally, some people with swine flu also have
reported runny nose, nausea, vomiting, & diarrhea
16. How can human infections with swine
influenza be diagnosed?
• To diagnose swine influenza A 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)
– Some persons, especially children, may shed virus for 10
days or longer
– Identification as a swine flu influenza A virus requires
sending the specimen to a laboratory for testing.
17. Is the H1N1 swine flu virus the same as
human H1N1 viruses?
• No, H1N1 swine flu viruses are antigenically very
different from human H1N1 viruses
• Vaccines for human seasonal flu do not provide
protection from this H1N1 set of swine flu viruses
18. How does swine flu spread?
• Human-to-human transmission of swine flu
predominantly occurs through direct droplet
transmission
• This is thought to occur in the same way as seasonal
flu, which is mainly person-to-person transmission
through coughing or sneezing of infected people
• People may become infected by touching something
with flu viruses on it & then touching their mouth or
nose (moist mucous membranes).
19. What should I do
if I think I may be sick?
• Stay home & reduce
the spread of
infectious diseases
• Utilize barrier
protection
• Utilize personal
protective equipment
(PPE)
20. How can I limit the spread of contact
transmission?
• Good hand hygiene or
hand washing
• Create a barrier
between yourself and
the virus
• Remove the virus
whenever possible
through good
cleansing of surfaces
21. What is a barrier?
• The first barrier is
distance
– If you are sick, stay
home
– If you suspect
someone of having the
virus then protect
yourself with person
protective equipment
(PPE) prior to entering
their 6 foot radius.
22. What is person protective
equipment (PPE)?
• Personal protective
equipment,
commonly referred
to as "PPE", is
equipment worn to
minimize exposure
to a variety of
hazards
23. What is PPE for medical providers
regarding droplet precautions?
• Wear a fit-tested N95 respirator, disposable gloves,
gown, & eye protection (face shield or goggles)
• Place a surgical mask on the patient & utilize devices
to reduce secretion distribution
• Before & after contact with respiratory infected
people:
– clean hands thoroughly with soap & water or an alcohol-
based hand gel.
24. What is good hand hygiene?
• Washing hand for
more than 15
seconds with soap
& water or apply an
alcohol-based
cleanser rubbing
hands until dry
25. When should you wash your hands with
soap & water?
Wash your hands with plain soap & water or with
antimicrobial soap & water if:
• your hands are visibly soiled (dirty)
• hands are visibly contaminated with blood or body
fluids
• hands come in contact with respiratory secretions
• before eating
• after using the restroom
26. Are alcohol-based
handrubs effective?
• More than 20 published studies have shown
that alcohol-based handrubs are more
effective than either plain soap or
antibacterial soaps in reducing the number of
live bacteria on the hands
27. Won’t frequent use of alcohol
dry out my skin?
• No! In fact, studies have proven that nurses who
routinely cleaned their hands between patients by
using a modern alcohol-based handrub had less skin
irritation and dryness than nurses who washed their
hands with soap and water
• Modern alcohol-based handrubs contain skin
conditioners (emollients) that help prevent the
drying effects of alcohol
28. Do I need a prescription for
hand cleansers?
• Most over-the-
counter skin
cleansers will
remove bacteria
and viruses if used
as directed
34. What medications are available to treat
swine flu infections in humans?
• At this time, CDC recommends the use of :
– Tamiflu (oseltamivir phosphate) or
– Relenza (zanamivir)
– As part of the treatment &/or reduction of
severity of infection with swine influenza
viruses
• More information on treatment
recommendations can be found at:
www.cdc.gov/flu/swine/recommendations.htm
35.
36. Is there a vaccine for swine flu?
• There is no vaccine
to protect humans
from swine flu at
this time
37. How can I reduce the spread of
infectious diseases?
• Good hand washing
• Universal precautions
at all times
• Respiratory droplet
precautions
– When an airborne
illness is suspected
Eighteen black nurses met at the home of Dr. Mary Harper and resolved to start a professional black organization that addressed both the needs of the African-American nurse but also the needs of the African American community. This took place on 12/18/1971. This historical event has blossomed into 79 chapters and over 150,000 members.
While there are three types of influenza viruses—A, B, and C—only two cause significant disease in humans (A and B). Type B influenza viruses are limited to humans, whereas Type A viruses can cause severe disease in humans and affect more species.
Influenza Type A
Type A influenza is considered to cause the most serious disease among the influenza viruses, although not all strains cause clinical disease. Influenza A can cause severe epidemics (as well as severe worldwide epidemics; or pandemics) among all ages. Influenza type A infects multiple species including people, birds, pigs, horses, and other animals. Wild birds are the natural hosts for these viruses.
Influenza Type B
Influenza B viruses are usually found only in humans. Influenza B viruses can cause some morbidity and mortality among humans, but in general are associated with less severe epidemics (chiefly among children) than influenza A viruses. Although influenza type B viruses can cause human epidemics, they have not caused pandemics.
Because avian influenza and all pandemic viruses are of the Type A variety, we will focus this session on Type A influenza viruses.
While seasonal influenza occurs every year, pandemic influenza rarely occurs. Here we compare some features of seasonal influenza with features of pandemic influenza.
While the population usually has some immunity built up from previous exposures to seasonal influenza, the human population lacks any immunity to pandemic influenza strains.
In seasonal influenza epidemics, infants and the elderly are most at risk of illness and complications. But during an influenza pandemic, even healthy, young people are at increased risk for serious complications.
Seasonal influenza strains are the result of Antigenic Drift, while pandemic influenza strains are the result of Antigenic Shift.
2 of the 3 prerequisites for a human pandemic have been met
A novel influenza virus has emerged and the general population has demonstrated little or no immunity
And the new virus has been able to replicate in humans
The main questions that remains are:
Will the virus will develop into a form that is efficiently transmitted from one human to another? (thus meeting the criteria for a pandemic)
If so, where, when, how quickly, and how severely?
The first two of three prerequisites have been met:
A novel virus
Virus must be able to replicate in humans and cause disease
New virus must be efficiently transmitted from one human to another
Virus can improve its transmissibility via two mechanisms:
adaptive mutation
genetic reassortment
(can take place in humans without prior adaptation in another mammalian species, such as the pig)
Eighteen black nurses met at the home of Dr. Mary Harper and resolved to start a professional black organization that addressed both the needs of the African-American nurse but also the needs of the African American community. This took place on 12/18/1971. This historical event has blossomed into 79 chapters and over 150,000 members.
It can be difficult to tell if a patient has influenza because the signs and symptoms for influenza are similar to those for other diseases that may cause respiratory illnesses. If you do suspect influenza, there are a few differences between human influenza and avian influenza that you can assess, especially in the early days of illness.
Human influenza usually causes both upper respiratory (sore throat runny nose) and lower respiratory (cough, bronchitis) symptoms. Common signs and symptoms include fever, headache, cough, sore throat, muscle ache, and exhaustion. Other respiratory symptoms may appear, varying from sore throat to difficulty breathing. Children and the elderly may also have gastrointestinal symptoms like diarrhea, vomiting and nausea, but adults uncommonly have gastrointestinal symptoms, except loss of apetitie. People generally recover anywhere from 2 to 7 days after symptoms appear. However, cough and muscle ache may last more than 14 days. Although influenza generally causes an upper respiratory infection with tracheobronchitis, it can progress to pneumonia and respiratory failure in some cases.
Although similar initially, avian influenza differs from human influenza in its course. Avian influenza leads to a lower respiratory illness with variable upper respiratory involvement. Initial symptoms are similar to human influenza. These include fever, headache, cough, sore throat, muscle ache, and exhaustion. Gastrointestinal symptoms of watery diarrhea, vomiting, and abdominal pain have been more commonly reported from H5N1 patients (20-70% diarrhea rate depending on case series). Symptoms of a lower respiratory infection appear early in course of the illness. About five days after symptoms appear, patients often begin to have difficulty breathing leading to respiratory distress, and an increased respiratory rate may also be observed. By this time, cough is prominent, sputum production may occur sometimes containing blood. Most patients develop pneumonia with bilateral pulmonary infiltrates.
Ref: Writing Committee on WHO Consultation. NEJM 353:1374-85, 2005
Eighteen black nurses met at the home of Dr. Mary Harper and resolved to start a professional black organization that addressed both the needs of the African-American nurse but also the needs of the African American community. This took place on 12/18/1971. This historical event has blossomed into 79 chapters and over 150,000 members.