The document discusses swine flu, also known as H1N1 virus. It begins by defining swine flu and describing the three main types of influenza viruses: A, B, and C. It then provides details on the history and outbreak of H1N1 virus in 2009 in Mexico and the United States. The document concludes by describing the viral structure, genome, mode of action, symptoms, diagnosis, and treatment options for swine flu.
3. Outline
What is swine flu
Types of influenza virus
History
Viral structure
Viral Genome
Mode of Action
Symptoms
Diagnosis
Drugs
4. Swine Flu
Swine influenza virus (SIV) or swine-origin
influenza virus (S-OIV) is also known as the
H1N1 virus, is a relatively new strain of an
influenza virus that causes symptoms similar
to the regular flu. It originated in pigs, but is
spread primarily from person to person.
5. Types
There are three different types of influenza virus :
Type A influenza virus (Most common and cause the most serious epidemics
multiple species)
Type B influenza virus (can cause epidemics but disease is less severe, generally
infecting only in humans)
Type C influenza virus (Not connected with epidemics more mild symptoms
infecting humans and swine)
6. History of H1N1
Early 2009 in Mexico
60 million Americans became infected
265,000 Americans were hospitalized
12,000 deaths occurred
WHO issued it the 1st pandemic declaration of 21th century.
7.
8. Structure
Influenza virus has a rounded shape and
has a layer of spikes on the outside.
There are two different kinds of spikes,
each made of a different proteins:
Hemagglutinin (HA) protein
Neuraminidase (NA) protein
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The HA protein allows the virus to stick to a cell, so that it can enter into a host
cell and start the infection process.
The NA protein is needed for the virus to exit the host cell, so that the new
viruses that were made inside the host cell can go on to infect more cells.
10. Subtypes or Strains
There are 17 different versions of HA and 10 different versions of NA.
A virus with version 1 of the HA protein and version 2 of the NA protein would be called
influenza A subtype H1N2 (A H1N2, for short).
11. Composition
The new virus is named influenza A (H1N1), although it is commonly referred to
as swine flu. Although it is called swine flu.
The new H1N1 virus is made up of a novel combination of segments from four
different influenza virus strains
Eurasian swine virus,
North American swine virus
Avian influenza virus
Human influenza virus
12.
13. Mode of Action
With the aid of envelope glycoprotein HA, influenza viruses can easily bind to
cell-surface glycosylated oligosaccharides that have sialic acids receptors at their
terminals, although this binding is very specific.
HA helps the virus to attach to the sialic acid receptor of the host cell, which is
followed by endocytosis. Viral RNA polymerase transcribes the viral genome and
releases the mRNA for further processing.
Mutations in the HA region of a virus may alter its binding affinity to the host.
15. Symptoms
The symptoms of swine flu are very much like those of
regular influenza. They include:
chills
fever
coughing
sore throat
runny nose
body aches
fatigue
diarrhea
vomiting