2. An acute respiratory illness caused by influenza viruses.
Affects the upper and/or lower respiratory tract.
Nearly every year outbreaks of illness occurs of variable
extent and disease severity.
Result in significant morbidity in general population and
increased in mortality rates among high-risk patients.
3. Shortness of breath
Pain or pressure in the
chest or abdomen
Dizziness
Confusion
Severe or persistent
vomiting
Flu-like symptoms
improve but then return
with fever and worse
cough
4. Dyspnoea
Bluish discoloration of skin
Not drinking enough fluids
Severe or persistent vomiting
Not waking up or not interacting
Irritable
Flu-like symptoms
5. Birth to 4 years old
Pregnant women
>65 years old
Long-term aspirin therapy
Disorders of the pulmonary or cardiovascular system.
Metabolic diseases
6. Outbreaks recorded virtually every year, their extent
and severity varies.
Localized outbreaks take place at variable intervals,
usually every 1–3 years.
The most recent pandemic emerged in March of 2009.
Caused by an influenza A/H1N1 virus that rapidly
spread worldwide over several months.
7. RNA viruses of orthomyxoviridae family ,influenza A, B, and
C viruses are clinically important.
A, B, or C is based on antigenic characteristics of the
nucleoprotein (NP) and matrix (M) protein antigens.
Influenza A viruses are further subdivided on the basis of
the surface hemagglutinin (H) and neuraminidase (N)
antigens .
individual strains are designated according to the site of
origin, isolate number, year of isolation, and subtype—for
example, influenza A/California/07/2009 (H1N1).
8. Influenza A has 16 distinct H subtypes and 9 distinct N
subtypes.
H1, H2, H3, N1, and N2 have been associated with
epidemics of disease in humans.
Influenza B and C viruses are similarly designated, H
and N antigens from these viruses do not receive
subtype designations.
Intratypic variations in influenza B :less extensive ,
In Influenza C virus: Absent
9. The hemagglutinin is the site by which the virus binds
to sialic acid cell receptors, whereas the neuraminidase
degrades the receptor and plays a role in the release of
the virus from infected cells after replication has taken
place.
14. Benefits of antiviral therapy
Shortening the duration of symptoms
Decreases the risk of complicated disease
Decreases viral shedding
Timing
Best if initiated with in <48 hrs of initiation
May still help after 48 hr if the symptoms are severe or
pregnant patient
15. Secondary bacterial infection
Retrospective pathological review suggested secondary
bacterial infection as the major cause of death in
pandemic H1N1 in 1918
Occurs several days after onset
Staphylocoocci aureus including MRSA
Nacrotizing pneumonia
Pneumatocele
Gram negative bacteria
16. Inhibitors of viral penetration and
uncoating
Amantadine
Rimantadine
Neuraminidase inhibitors
Oseltamavir
Zanamavir
Peramivir
17. Amantadine and its -methyl derivative rimantadine are
uniquely configured tricyclic amines.
18. They inhibit an early step in viral replication, viral
uncoating.
Have an effect on a late step in viral assembly.
Site of action :M2 protein, an integral membrane
protein that functions as an ion channel.
Drug inhibit the acid-mediated dissociation of the
ribonucleoprotein complex in replication.
19. Side effects include :
nervousness,
light-headedness,
difficulty concentrating,
insomnia, and
loss of appetite
Nausea & vominting
Ankle edema
20. Seasonal prophylaxis: amantadine or rimantadine (200
mg/day) is ~70-90% protective against influenza A illness.
Pandemic influenza, in preventing nosocomial influenza
and outbreaks.
Treatment : Influenza A , modest effect
(100mg bd x 5 days)
21. First orally active neuraminidase inhibitor
Mechanism of action
Oseltamivir is a prodrug
Competitive inhibitor of
sialic acid, found on the surface proteins of normal host
cells
Blocking the activity of the viral neuraminidase enzyme,
oseltamivir prevents new viral particles from being
released by infected cells
22.
23. Dosing
Given to >1 yr of age
TREATMENT :75 mg twice daily for 5 days
PROPHYLACTIC : 75 mg once daily for 14 days shown to
be safe and effective for up to six weeks
24. Side effects
Common ADRs:-Nausea, vomiting, diarrhea,
abdominal pain, and headache.
Rare ADRs include: hepatitis and elevated liver
enzymes, rash, allergic reactions including
anaphylaxis, and Stevens-Johnson syndrome
Postmarketing surveillance: toxic epidermal
necrolysis, cardiac arrhythmia, seizure, confusion,
aggravation of diabetes
25. Zanamivir is a sialic acid analog tha inhibits the
neuraminidases of influenza A and B viruses.
Pharmacokinetic data
Bioavailability- 2% (oral)
Protein binding- <10%
Metabolism- Negligible
Half life- 2.5–5.1 hours
Excretion- Renal
Routes- Inhalation
26. Mechanism of action
Zanamivir works by binding to the active site of the
neuraminidase protein, rendering the influenza virus
unable to escape its host cell and infect others.
It is also an inhibitor of influenza virus replication in
vitro and in vivo
27. Dosing
Two inhalation (10 mg per puff) twice a day for 5 days
After inhalation, zanamivir is concentrated in the lungs
and oropharynx,
15% of the dose is absorbed and excreted in urine
28.
29. Side effects
Headache
Bronchospasm and cough (contraindicated in asmatics)
Zanamivir has not been known to cause toxic effects,
does not spread around through the body's systemic
circulation and
No signs of viral resistance from any flu
30. Age group (in years)
Antiviral drug Children≤ 12 13-64 ≥65
Oseltamivir
Treatment (A&B) <15 kg: 30 mg bd; >15–23 kg: 45
mg bd; >23–40 kg: 60 mg bd
75mg po bd 75mg po bd
Prophylaxis(A&B) <15 kg: 30 mg od; >15–23 kg: 45
mg od; >23–40 kg: 60 mg od
75mg od 75mg od
Zanamivir
Treatment (A&B) 10mg bd inhalation 10mg bd 10mg bd
Prophylaxis(A&B) 10mg od 10mg od 10mg od
Amantadine
Treatment (A) Age 1–9, 5 mg/kg in 2 divided
doses, up to 150 mg/d
Age 10, 100 mg
PO bd
≤ 100 mg/d
Prophylaxis, (A) Age 1–9, 5 mg/kg in 2 divided
doses, up to 150 mg/d
Age 10, 100 mg
PO bd
≤ 100 mg/d
Rimantadine
Treatment, (A) Not approved 100 mg PO bd 100–200 mg/d
Prophylaxis, (A) Age 1–9, 5 mg/kg in 2 divided
doses, up to 150 mg/d
Age 10, 100 mg
PO bd
100–200 mg/d
31.
32. Avoid close contact
With sick people. Keep safe distance
Stay home when you are sick
If possible, stay home from work, school and office
Cover your mouth and nose
Cover mouth and nose with tissue when coughing or
sneezing
Clean your hands
Frequent hand washing will protect you from germs
Avoid touching your eyes, nose or mouth
33. Drink plenty of fluids and eat nutritious food
Get plenty of sleep to be physically active.
Manage your stress.
Get treatment and/or prevention of the infection with
antiviral drugs.
35. Facemasks (disposable, single use masks) for
persons who enter crowded settings
Respirators (N95 or higher filtering facepiece
respirator) for persons who have unavoidable close
contact with infectious person
No clear scientific evidence regarding the effectiveness of facemasks
and respirators in protecting against influenza
When contact is unavoidable
36. Medical institutions
To maintain good infection control
Schools
To perform preventive measures such as morning
inspection, temperature measurement, school
suspension for the sick, outbreak notification
37. The influenza vaccine, also known as flu shot, is an
annual vaccination using a vaccine specific for a given
year to protect against the highly variable influenza virus
Two types of influenza vaccines are available:
TIV :of trivalent (three strains; usually A/H1N1, A/H3N2,
and B) inactivated (killed) vaccine)
LAIV: (nasal spray )of live attenuated influenza vaccine
38. Mechanism of action
TIV works by putting into the bloodstream those parts
of three strains of flu virus that the body uses to create
antibodies
LAIV works by inoculating the body with those same
three strains, but in a modified form that cannot cause
illness.
Prepration
Pandemrix by GlaxoSmithKline (GSK)
Focetria by Novartis