4. Anitgenic Drift
Mutation That Take Place Within The Genome
Causes Changes In Hemagglutinin And Neuraminidase Of
Influenza Virus Due To Point Mutations
This Involves No Change In Serotype; There Is Merely An
Alteration In Amino Acid Sequence Of HA Or NA Leading To
Change In Antigenicity.
Drift Variants Can Cause Epidemics And Lasts For 2 To 5 Years,
Before Being Replaced By A Different Strain.
5. ANTIGENIC SHIFT
Re-assortment (mixing of genetic
meterial ) among the genetic materials
of subtypes resulting in A new virus.
Involves major antigenic changes in
which a new HA or NA subtype is
introduced into the human population.
Caused by reassortment, typically between
human , avian and swine strains.
• Double reassortment
7. PATHOGENESIS
High affinity for the tracheal cells with sialic acid receptors. HA
ataches to Sialic acid receptors. Preferentially binds to the N-
acetylneuraminic acid attatched to the penultimate glucose sugar
by α 2,6 linkage. (2,3 linkage for avian flu)
the virus multiplies in bronchial epithelium within 16 hr of
infection and causes
focal necrosis of the bronchial epithelium,
focal atelectasis, and gross hyperemia of the lungs.
Epithelial cell damage
Airway plugging
8. TRANSMISSION
Short incubation period, usually 1-4 days.
Source of infection -Case or sub-clinical case
Reservoir of Infection - Human
Spread by respiratory droplets
Person to person,
Direct contact, rare aerosol
Highly contagious
INFECTIOUS PERIOD:
üAdults: 1 day prior to symptoms & 5 days post illness starts
üChildren: >10 days
üImmune compromised shed virus for weeks to months
Virus is detectable just before symptom onset.
Usually not detectable after 5-10 days
People with flu can spread it to others up to about 6 feet away
9. SWINE FLU SYMPTOMSSWINE FLU is a contagious respiratory illness caused
by flu viruses. It can cause mild to severe illness, and at
times can lead to death. The flu is different from a
cold. The flu usually comes on suddenly.
People who have the flu often feel some or all of these
symptoms:
Fever* or feeling feverish/chills
Cough
Sore throat
Runny or stuffy nose
Muscle or body aches
11. Emergency Warning Signs
.In adults:
•
Difficulty breathing or shortness of
breath
•
Pain or pressure in the chest or
abdomen
•
Sudden dizziness
•
Confusion
•
Severe or persistent vomiting
•
Flu-like symptoms improve but then
return with
fever and worse cough
12. SYMPTOMS IN CHILDREN
•
Fast breathing or trouble breathing
•
Red or grey rash on skin
•
Not drinking enough fluids
•
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
•
Fever with a rash
13. Emergency warning signs in
children
Fast breathing or trouble breathing
Bluish or gray skin color
Not drinking enough fluids
Severe or persistent vomiting
Not waking up or not interacting
Irritable, the child does not want to be held
Flu-like symptoms improve but then return
with fever and worse cough
14. HIGH RISK CASESAdults 65 years and older
Children younger than 5 years old, but especially children
younger than 2 years old
Pregnant women and women up to 2 weeks after the end of
pregnancy
Asthma , Chronic lung disease (COPD] and cystic fibrosis
DIABETES
congestive heart failure and coronary artery disease)
Morbid obesity
Kidney disorders
Liver disorders
Weakened immune system due to disease or medication
(such as people with HIV or AIDS, or cancer, or those on chronic steroids)
15. Smoking and Influenza
Some research studies show an increase in influenza
infections among smokers compared to nonsmokers.
There is a higher mortality rate for smokers than
nonsmokers from influenza.
16. Diagnostic Tests
Influenza
Diagnostic
Tests
Method Availability Typical
Processing
Time2
Sensitivity3
for
H1N1
influenza
Distinguishes
H1N1
influenza
from other
influenza A
viruses?
Rapid influenza
diagnostic tests
(RIDT)4
Antigen detection Wide 0.5 hour 10 – 70% No
Direct and indirect
Immunofluorescence
assays (DFA and
IFA)5
Antigen detection Wide 2 – 4 hours 47–93% No
Viral isolation in
tissue cell
culture
Virus isolation Limited 2 -10 days - Yes 6
Nucleic acid
amplification
tests
(including rRT-
PCR) 7
RNA detection Limited8 48 – 96
hours
[6-8 hours to
perform test]
86 – 100% Yes
17. SAMPLE COLLECTION.
Respiratory specimens including:
v bronchoalveolar lavage,
v tracheal aspirates,
v nasopharyngeal or oropharyngeal aspirates as washes, and
v nasopharyngeal or oropharyngeal swabs.
Swab specimens should be collected only on swabs with a synthetic tip
(such as polyester or Dacron) and aluminium or plastic shaft.
Swabs with cotton and wooden shafts are not recommended. Specimens
collected with swabs made of calcium alginate are acceptable.
BEST TIME TO TAKE SAMPLE
Sample need to be collected within the first 4 to 5 days of illness (when an
infected person is most likely to be shedding virus).
18. Throat Swab
•
Highest yield in detecting H1N1
influenza in suspected cases
•
Have the patient open his/her mouth
wide open.
•
Sample should be collected from
back of the throat near the tonsils.
19. Nasal / Nasopharyngeal Swab
Insert dry swab into nostril and back to
nasopharynx
Leave in place for a few seconds. Slowly remove
swab while slightly rotating it.
Use a different swab for the other nostril. Put
tip of
swab into vial containing VTM
Nasal Swab is collected from the anterior
turbinate.
20.
21. ANTIVIRAL TREATMENT
There are two flu antiviral drugs recommended
Oseltamivir or Zanamivir
Use of anti-virals can make illness milder and recovery faster
They may also prevent serious flu complications
For treatment, antiviral drugs work best if started soon after
getting sick (within 2 days of symptoms)
Source: CDC
22.
23.
24. Source: CDC
OSELTAMIVIR (TAMIFLU) ZANAMIVIR (RELENZA)
Treatment Prophylaxis Treatment Prophylaxis
ADULTS 75 mg capsule
twice per day for
5 days
75 mg OD
for 7-10 days
Two 5 mg
inhalations (10
mg total) BD
Two 5 mg
inhalations (10
mg total) OD
CHILDREN 15 kg or less: 30
mg BD
30 mg OD Two 5 mg
inhalations (10
mg total) BD
(age, 7 years or
older)
Two 5 mg
inhalations (10
mg total) OD
(age, 5 years
or older)
15–23 kg: 45 mg
BD
45 mg OD
24–40 kg: 60mg
BD
60 mg OD
>40 kg: 75mg
BD
75 mg OD
ANTIVIRAL PROTECTION
25. OSELTAVIR(PRODRUG)
MECHANISM OF ACTION
in the LIVER it is hydrolyzed to its active metabolite - the free Oseltamivir
carboxylate.Oseltamivir is a competitive neuramidase inhibitor. By blocking the
activity of the enzyme, oseltamivir prevents new viral particles from being released
through the cleaving of terminal sialic acid on glycosylated hem agglutinin and thus fail to
facilitate virus release.
PHARMACOKINETICS
Its Oral bioavailability is over 80% and is extensively metabolised to its active form upon
first-pass through the liver.[
Its half-life is about 1–3 hours and its active metabolite has a half-life of 6–10 hours.
It is predominantly ELIMINATED IN THE URINE as the active carboxylate metabolite
(>90% of oral dose)
MOST COMMON SIDE EFFECTS:
Nausea, vomiting, abdominal pain, ear disorder, and diarrhea
DRUG INTERACTIONS:
Co administration of oseltamivir and probenecid resulted in reduced clearance of
Oseltamivir carboxylate by approximately 50% and a corresponding approximate two-fold
increase In the plasma levels of oseltamivir carboxylate
26. Oseltamivir, zanamivir, rimantadine, and
amantadine are “Pregnancy Category C” few
adverse events have been reported occasionally in
pregnant women who took these medications, no
causal relation between the use of these medications
and these adverse events has been established . In
addition, fever can cause adverse fetal outcomes, and
reducing fever, whether directly by using antipyretics,
or indirectly by reducing the duration and severity of
symptoms with antiviral medications, might reduce
this risk
. One retrospective cohort study found no evidence of
an association between oseltamivir use during
pregnancy and a variety of adverse events, including
preterm birth, premature rupture of membranes,
PREGNANT WOMEN
27. PREVENTION
Recent studies* by CDC researchers and other experts
indicate that flu vaccine reduces the risk of doctor visits due
to flu by approximately 60% among the overall population
when the vaccine viruses are like the ones spreading in the
community.
28. Live Attenuated (Human) Influenza Vaccine
NASOVAC-S, Influenza Vaccine, (Human), freeze dried is a live
trivalent vaccine for administration by intranasal spray
COMPOSITION
[Propagated in Embryonated hen eggs]
Each vial of single dose (0.5 ml) contains:
A(H1N1) Strain –
A/17/California/2009/38 (H1N1)* Not less than 107 EID 50
A(H3N2) Strain
- A/17/Texas/2012/30 (H3N2)* Not less than 107 EID 50
B Strain
- B/60/Massachusetts/2012/10* Not less than 106.5 EID 50
29. Reconstitute with Sterile Water for Inhalation USP
Dose: 0.5 ml intranasal (spray 0.25 ml per nostril)
The diluent supplied is specially designed for use with the vaccine.
Only this diluent must be used to reconstitute the vaccine. Do not
use diluents from other types of vaccine or from other
manufacturers.
Using an incorrect diluent may result in damage to the vaccine
and/or serious reactions to those receiving the vaccine. Diluent
must not be frozen, but should be kept cool.
ADVERSE REACTIONS
Local : Nasal discomfort, stuffy nose, sneezing, runny nose, loss of
smell, red eyes, chills, facial swelling.
Systemic : Fever, headache, fatigue, myalgia, arthralgia, irritability,
loss of appetite, sore throat, cough, wheezing, nausea.
30. Nasal Spray Flu Vaccine
The nasal spray vaccine is approved for use in people 2 years
through 49 years of age.
CONTRAINDIACTED IN:
Children younger than 2 years & Adults 50 years and older
People with a history of severe allergic reaction to any
component of the vaccine or to a previous dose of any
influenza vaccine
People who are allergic to eggs
Children or adolescents (2 years through 17 years of age) on
31. STORAGE
2 - 8ºC (35-46ºF)
Difference in the efficacy of intranasal and
injectable flu vaccines ?
Several studies have proved that the clinical efficacy
of intranasal vaccine is superior to that of injectable
vaccine.
Injectable vaccines protect only at the level of the
32. VACCINATE EVERY YEAR ?
The flu viruses are constantly changing .Generally new
influenza virus strains circulate every flu season. Each
Year, before flu season, the most recent circulating
viruses are identified by the World Health
Organization [WHO] and included in a new vaccine
formula order to offer the best protection.
33. FLU COMPLICATIONSMost people who get influenza will recover in a few days
to less than two weeks, but some people will develop
complications (such as pneumonia) as a result of the flu,
some of which can be life-threatening and result in death.
Pneumonia, bronchitis, sinus and ear infections are
examples of complications from flu. The flu can make
chronic health problems worse.
For example, people with asthma may experience
asthma attacks while they have the flu, and people with
chronic congestive heart failure may experience worsening
of this condition that is triggered by the flu.
36. Why The Flu Virus Is More Infectious In
Cold Winter TemperaturesAt winter temperatures, the virus's outer covering, or
envelope, hardens to a rubbery gel that could shield the
virus as it passes from person to person, the researchers
have found. At warmer temperatures, however, the
protective gel melts to a liquid phase. But this liquid
phase apparently isn't tough enough to protect the virus
against the elements, and so the virus loses its ability to
spread from person to person.
37. OTHER REASONS
During the winter, people spend more time indoors with the
windows sealed, so they are more likely to breathe the same air
as someone who has the flu and thus contract the virus .
Days are shorter during the winter, and lack of sunlight leads
to low levels of vitamin D and melatonin, both of which
require sunlight for their generation. This compromises our
immune systems, which in turn decreases ability to fight the
virus .
The influenza virus may survive better in colder, drier
climates, and therefore be able to infect more people .
Cold temperatures lead to drier air, which may dehydrate
mucous membrane preventing the body from effectively
defending against respiratory virus infections.
38. Source: Bean B, et al. JID 1982;146:47-51
Survival of Influenza Virus Surfaces and
Affect of Humidity & Temperature*
Hard non-porous surfaces 24-48 hours
Plastic, stainless steel
Recoverable for > 24 hours
Transferable to hands up to 24 hours
Cloth, paper & tissue
Recoverable for 8-12 hours
Transferable to hands 15 minutes
Viable on hands <5 minutes only at high viral titers
Potential for indirect contact transmission
*Humidity 35-40%, Temperature 28C (82F)
39. Swine flu H1N1 BIRD FLU H5N1
Swine flu spreads quickly as comparison
to bird flu, but casualty rate not much
high
Bird flu spreads very slowly, but has a
high casualty rate.
Swine flu virus affects only the respiratory
system.
The bird flu virus affects all systems of
human body
The main symptoms of swine influenza
are vomiting and diarrhea. Apart from
cough, fever, sore throat
Bird flu patients suffer from eye
infections, pneumonia, and other
severe problems.
Where as swine flu is transmitted from
direct contact with pigs, waste matter
contaminated by infected people
Bird flu is transmitted by direct contact
with birds, their excretory products
contaminated by infected people.
Pregnant women, persons with chronic
medical conditions are most vulnerable
target for swine influenza,
Small children and rural workers are
soft target to get infected from bird flu.
Spread from person to person Less spread from person to person
40. SAFTEY MEASURES TO PREVENT INFECTION
Wear Glouses
Use Protective Eye Wear (Goggles)/Face Shields
Person Must Wash Their Hands Often – Especially After Handling
Infectious Materials And , Before Leaving The Laboratory Working Areas,
And Before Eating.
Appropriate Disinfectants
70 % Ethanol
5 % Lysol
10 % Bleach
41. Hand Washing
Wet hands with clean (not hot)
water
Apply soap
Rub hands together for at least
20 seconds
Rinse with clean water
Dry with disposable towel or
air dry
Use towel to turn off faucet
42. Good Health Habits Can Help
Stop flu
1. Avoid close contact.
2. Stay home when you are sick.
3. Cover your mouth and nose.
4. Clean your hands. WITH
alcohol-based hand rub.
43. Summary
• WHO raised the alert level to Phase 6 on June 11, 2009
• Influenza transmission remains active in much of western and central Asia and
there is evidence of pandemic virus circulation in most regions of Africa
• The overall global case-fatality is ~1%
• Symptoms mimic seasonal flu
• 1:1 Male:Female Ratio
• Globally
– Number of deaths being reported is rising
• Vaccine
– Total Adverse Events: 5.4% (0.3% fatal)
• Anti-virals (oseltamivir and zanamivir)
– Oseltamivir resistance reported recently in immunocompromised patents
