swine flu
What is swine influenza (flu)?
•Swine influenza is a respiratory disease of of pigs caused by type A influenza virus(H1N1).
•Swine flu viruses (SIV) do not normally infect human beings.
•This is the disease of swine (pigs).
History
•The H1N1 form of swine flu is one of the descendants of the Spanish flu that caused a pandemic in humans in 1918–1919.
•For almost 60 years, from the first isolation in 1930 through 1998, SIV strains were almost exclusively H1N1
• In 1997-1998, H3N2 strains emerged
•Swine influenza (also called swine flu, hog flu, and pig flu) refers to influenza caused by any strain of the influenza virus endemic in pigs (swine).
•Strains endemic in swine are called swine influenza virus (SIV).
•Of the three genera of human flu, two are endemic also in swine:
• Influenzavirus A is common and Influenzavirus C is rare.
•Influenzavirus B has not been reported in swine.
CAUSED BY GENETIC RE-ASSORTMENT OF DIFFERENT STRAINS
•The 2009 flu outbreak in humans that is widely known as "swine flu" is due to a new strain of influenza A virus subtype H1N1 that derives by genetic reassortment from one strain of human influenza virus, one strain of avian influenza virus, and
two separate strains of swine influenza virus
SWINE FLU DIFFER FROM HUMAN FLU
»The H1N1 strain virus are antigenically different from those of human type of H1N1 strain virus.
•Therefore vaccines for human seasonal flu does not provide protection from H1N1 strain of swine flu viruses.
PRESENT SWINE FLU STRAINS
•At this time, there are four different types of influenza A strains of viruses in pigs.
•They are 1. H1N1
2. H1N2
3. H3N1 and
4. H3N2.
CAN CLOSE PROXIMITY SPREAD THE DISEASE?
•Yes, influenza viruses can directly be transmitted from pigs to human beings and from humans to pigs.
•Close proximity to infected pigs such as pig barns, livestock exhibit, and housing pigs at farms.
•Human to human transmission of swine flu can also occur.
in swine
•Fever,
•Lethargy
•Sneezing
•Coughing
•Weight loss
•Poor growth
In humans
Fever
Running nose
Coughing
Diarrhea
Loss of appetite
Signs and symptoms
Transmission
•Transmission between pigs:
The main route of transmission is through direct contact between infected and uninfected animals
Airborne transmission through the aerosols produced by pigs coughing or sneezing are also an important means of infection
Transmission to humans
•People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals
•The 2009 swine flu outbreak is an apparent reassortment of several strains of influenza A virus subtype H1N1, including a strain endemic in humans and two strains endemic in pigs, as well as an avian influenza.
prevention
•Prevention of swine influenza has three components:
• prevention in swine,
• prevention of transmission to humans, and
• prevention of its spread among humans
Prevention in swine
•Methods of preventing the spread of influenza among swine include facility management, herd management, and vaccination.
•Present vaccination strategies for SIV control and prevention in swine farms, typically include the use of one of several bivalent SIV vaccines commercially available.
Prevention in humans
•Prevention of pig to human transmission: The transmission from swine to human is believed to occur mainly in swine farms where farmers are in close contact with live pigs.
•farmers and veterinarians are encouraged to use a face mask when dealing with infected animals.
•Hand washing.
•Using hand kerchief while sneezing.
•Prevention of human to human transmission:
• Influenza spreads between humans through coughing or sneezing and people touching something with the virus on it and then touching their own nose or mouth
• Swine flu cannot be spread by pork products, since the virus is not transmitted through food.
Treatment
•In swine: As swine influenza is not usually fatal to pigs, little treatment is required.
•Vaccination and animal management techniques are most important in these efforts.
Recommendations
Strengthen national disease surveillance, prevention, control and response system
►Requires a commitment of States Parties
Mobilization of national resources: e.g. staff, infrastructure, budget
Development of national action plans, integrated and coordinated with
intermediate and local levels and points of entry (ports, airports, ground crossings)
►Builds on existing national and regional strategies
► Requires sustained multisectorial approach and international collaboration
Responsibilities of Countries
• Develop, strengthen, and maintain core public health capacities for surveillance and response
• Identify a National IHR Focal Point for 24/7 communication with WHO
• Notify WHO of potential public health emergencies of international concern
• Immediately report to WHO outbreaks of smallpox, polio, new strains of human influenza, and SARS
• Respond to public health risks that may spread internationally.
