2. Definition
• It can be defined as a respiratory disease of pigs
caused by type A influenza viruses that causes
regular outbreaks in pigs.
• Human infections can and do happen.
• Swine flu, Hog flu, and Pig flu
3. • When influenza viruses from different species infect pigs, the
viruses can re-assort (i.e. swap genes) and new viruses , a mix of
swine, human and/or avian influenza viruses - can emerge
leading to development of new novel strain for which human
beings do not have no immunity.
• There are four main influenza type A virus subtypes that have
been isolated in pigs: H1N1, H1N2, H3N1 and H3N2. However,
most of the recently isolated influenza viruses from pigs have
been H1N1 viruses.
• GENETIC SEQUENCING SHOWS H1N1 virus with segments from 4
influenza viruses – North American swine+ north American avian
+ human influenza + euroasian swine
4. • genetic re-assortment ( co-infection with
influenza virus from diverse animal species)
• pigs – “Mixing Vessels” – avian & human
viruses
5. ANTIGENIC CHARACTERIZATION
• March 2009 pandemic -H1N1 influenza A virus .
• Quadruple reassortment of two swine strains, one
human strain, and one avian strain of influenza .
• 30.6 percent from North American swine influenza
strains,
• 17.5 percent from Eurasian swine influenza strains,
• Followed by North American avian influenza strains
(34.4 percent) and
• Human influenza strains (17.5 percent)
10. Sequence of events
• A novel influenza A (H1N1) virus of swine origin
emerged among people in Mexico during the spring of
2009 (march18) and spread with travelers worldwide.
• On 11th June, 2009, World Health Organization
declared this a pandemic
• As of October 2009, over 200 countries have reported
confirmed human cases of pandemic (H1N1) 2009.
11. • After Mexico, subsequent confirmed cases in
USA, Canada , U.K., Australia, Brazil, France ,
Israel, New Zealand
• On April 26, 2009 – Declared a National Public
Health Emergency by the US Deptt of Health &
Human Services
• On April 27, 2009 – Health services in India
were put on high alert
12. Current Indian scenario (till 14th April 2011)
• Death toll risen to 21
• Most of the deaths in Mahararshtra, though
Rajasthan, Andra has also reported
• > 300 have been infected with H1N1 virus
13. • The pandemic (H1N1) 2009 influenza virus differs in its
pathogenicity from seasonal influenza in two key aspects.
• First, as the majority of human population has little or no
pre-existing immunity to the virus, the impact of the
infection has been in a wider age range, in particular
among children and young adults.
• Secondly, the virus can infect the lower respiratory tract
and cause rapidly progressive pneumonia especially in
children and young to middle-aged adults.
• High morbidity , low mortality (1-4%)
14. CDC (DEC 09)
SUMMARY OF STATISTICS - CDC
Official US Total:
(According to CDC)
44640 cases, 10837 deaths
Unofficial US Total:
(Other Reliable Sources)
115431 cases, 10837 deaths
Worldwide Total:
(Various Reliable Sources)
1483520 cases, 25174 deaths
Most Infected States:
(According to CDC)
Wisconsin: 6222 cases
Texas: 5151 cases
Illinois: 3404 cases
Most Infected Countries:
(Various Reliable Sources)
Germany: 222006 cases
Portugal: 166922 cases
China (Mainland): 120940 cases
15. Death Rate per Infection- DEC 09
Country Cases Deaths % Dead Frequency
India 29303 1302 4.44% 1 in 23
17. PUNJAB
• 30 per cent rise in the number of H1N1 flu
(swine flu) patients due to change of season
• 24 confirmed cases of the pandemic
• More than 700 contacts of these 24 patients
too have been administered prophylactic
treatment
18. TRANSMISSION
• Pigs to people
• People to pigs.
• Human-to-human
• Transmission through coughing or sneezing by
people infected with the influenza virus.
• Human infection with flu viruses from pigs are
most likely to occur when people are in close
proximity to infected pigs, such as in pig barns
and livestock exhibits housing pigs at fairs.
19. • Cold and dry weather
• Not transmitted by food.
• Eating properly handled and cooked pork (at
an internal temperature of ≥160°F) and pork
products is safe.
20. RISK FACTORS
• Chronic pulmonary disease (e.g. asthma, COPD),
chronic cardiac disease (e.g. congestive cardiac failure),
metabolic disorders (e.g. diabetes), chronic renal
disease, chronic hepatic disease, certain neurological
conditions (including neuromuscular, neurocognitive,
and seizure disorders), hemoglobinopathies
• Immunosuppression, whether due to primary
immunosuppressive conditions, such as HIV infection,
or secondary conditions,such as immunosuppressive
medication or malignancy
21. • Infants and young children, in particular <2 yrs
• Pregnant women
• Children receiving chronic aspirin therapy
• Persons aged 65 years and older
22. • Incubation period is 1 to 7 days
• Communicability 1 day before to 7 days after
the onset of symptoms
23.
24. • Symptoms and signs suggesting oxygen impairment or
cardiopulmonary insufficiency:
• - Shortness of breath (with activity or at rest), difficulty
in breathing, turning blue, bloody or coloured sputum,
chest pain, and low blood pressure
• In children, fast or laboured breathing; and
• Hypoxia, as indicated by pulse oximetry.
25. • Symptoms and signs suggesting CNS
complications:
• Altered mental status, unconsciousness,
drowsiness, or difficult to awaken and
• recurring or persistent convulsions (seizures),
confusion, severe weakness, or
• paralysis.
26. • Evidence of sustained virus replication or invasive
secondary bacterial infection based on laboratory
testing or clinical signs (e.g. persistent high fever
and other symptoms beyond 3 days).
• Severe dehydration, manifested as decreased
activity, dizziness, decreased urine output, and
lethargy
27. SUSPECTED CASE
• A person with acute febrile respiratory illness (fever =
38⁰C) with onset
• Within 7 days of close contact with a person who is a
confirmed case of swine influenza(H1N1 virus
infection)
• Within 7 days of travel to areas where there are one or
more confirmed cases of swine influenza (H1N1 virus
infection)
• Resides in a community where there are one or more
confirmed cases of swine influenza.
28. PROBABLE CASE
• Positive for influenza A, but unsubtypable for H1 and H3 by
influenza RT-PCR or reagents used to detect seasonal
influenza virus infection
• Positive for influenza A by an influenza rapid test or an
infuenza immunofluorescence assay (IFA) plus meets criteria
for a suspected case
• Individual with a clinically compatible illness who died of an
unexplained acute respiratory illness who is considered to be
epidemiologically linked to a probable or confirmed case
29. CONFIRMED CASE
• A person with an acute febrile respiratory illness
with laboratory confirmed swine influenza A(H1N1)
virus infection at WHO approved laboratories by one
or more of the following tests:
1. Real Time PCR
2. Viral culture
3. Four-fold rise in swine influenza A(H1N1) virus
specific neutralising antibodies.
32. Samples being sent to..
• Post Graduate Institute of Medical Education
and Research
NICD, Delhi
• NIV, Pune
33. SPECIMENS
• Nasopharyngeal swab
• Nasal aspirate
• Combined nasopharyngeal swab with
oropharyngeal swab.
• Nasal swab
• oropharyngeal swab
• intubated patients - an endotracheal aspirate .
bronchoalveolar lavage (BAL) and sputum
specimens also acceptable.
34. Time of specimen collection
• Soon after symptoms begin
• Before administration of antiviral medications
• Even if symptoms began > 1 week ago
• Multiple specimens on multiple days can be
collected
35. • Swabs with a synthetic tip (polyester or Dacron)
and an aluminium or plastic shaft preferred
• Swabs with cotton tips and wooden shafts not
recommended.
• Swabs made of calcium alginate not acceptable.
• Collection vial for swab should contain 1 to 3 ml
of viral transport media.
36. Biosafety measures for specimen collection
• Collection by trained hospital / lab staff
• N95 masks should be used while taking samples & if
they are not available, triple layer well fitted surgical
facemasks can be used
• disposable latex gloves
• lab coat / disposable apron
• Head cover
• Use of protective eyewear (goggles)/faceshields if
procedure likely to generate aerosols, or splashes of
secretions
40. Nasopharyngeal Swab
• Insert a dry swab into the nostril and take it
back to the nasopharynx
• Leave in place for a few seconds
• Slowly remove it while slightly rotating it
• New swab for other nostril
Nasal Swab
• Collected from the anterior turbinate
41.
42. Nasopharyngeal aspirates
• 3 to 7 ml saline introduced through the nose
and aspirated by a small tubing inserted into
the other nostril
43.
44. Throat Swab
• Patient’s mouth should be wide open
• Touch the swab at the back of the throat near
the tonsils
45.
46.
47.
48. Viral transport media
• Protein – stabilizes the virus (serum ,albumin, gelatin)
• Foetal calf serum – less inhibitory factors, antibodies
• Buffers- pH maintenance
• Antifungals, antibacterials –
• Penicillin(500units/ml)
• Streptomycin(500 to 1000 units/ml)
• Vancomycin(20mcg/ml)
• Gentamicin(50mcg/ml)
• Amphotericin(10mcg/ml)
• Phenol red – pH indicator – ensure that medium is suitable
• Cryoprecipitate to preserve the viruses during long storage
49. • Stuarts medium, Amies medium
• Leibovitz-Emory medium
• Hanks balanced salt solution
• Eagles tissue culture medium
50. Labelling Of Specimens
• Pre-printed barcode labels to be used
• On the specimen container
• On the field data collection form
• On the log book
51. Specimen Storage
• Within 48 hours → store at 4° C before and
after transport
• Beyond 48 hours → −70 ° C
• Do not store in standard freezer- keep on ice
or in refrigerator
52. Transport
• All specimens should be
transported after packaging
using the WHO triple
packaging system.
• While transportation cold
chain should be maintained.
53. Triple Packaging System
1. Primary receptacle: a labelled primary watertight,
leak-proof receptacle containing the specimen.
2. Secondary receptacle: a second durable,
watertight, leak-proof receptacle to enclose and
protect the primary receptacle(s).
3. Outer package: the package around the secondary
receptacle which protects the receptacle and its
contents from outside influences such as physical
damage while in transit.
55. Test Method Infuenza Virus
Types Detected
Time For Results
Virus Culture A and B 5 – 10 days
Fluorescent
Immunoasssay
A and B 2 – 4 hrs
RT - PCR A and B 1 -2 days
Serological Tests A and B > 2 weeks
Enzyme Immunoassay
(EIA)
A and B 2 hours
Rapid Antigen Detection A ; A and B < 30 mins
56. • Diagnostic Tests
• Demonstration of virus antigen (IF , PCR)
• Isolation of virus
• Serology
• Other tests
57. Immunofluorescence (DFA or IFA)
• Done using fluorescent tagged influenza antiserum
• Distinguishes between influenza A and B .
• positive for influenza A by immunofluorescence may meet
criteria for a suspected case.
• Not possible to differentiate from seasonal influenza a viruses
• A negative DFA or IFA does not exclude H1N1 influenza A
infection .
• should not be assumed a final diagnostic test for novel
influenza A (H1N1) virus infection.
58.
59. PCR
Several PCR assays for detection of:
• Highly conserved parts of the influenza genome (matrix
‘M’ gene) to confirm the presence of influenza A
• Detect current human influenza virus H1 and H3 genes
• When the result of PCR assay on ‘M’ gene is ‘negative’, the
diagnosis of Influenza could be ruled out.
• When the PCR ‘M’ gene is positive together with either PCR
H1/H3 is positive, human influenza is diagnosed
60. • Real-time RT-PCR is the recommended test for
confirmation of novel influenza A (H1N)1 cases.
• Currently, novel influenza A (H1N1) virus will test
positive for influenza A and negative for H1 and H3
by real-time RT-PCR.
• If reactivity of real-time RT-PCR for influenza A is
strong it is more suggestive of a novel influenza A
(H1N1) virus
61. Cell Culture
• Done in monkey kidney cells or human embryo
kidney cells
• Isolation of H1N1 influenza A virus using culture is
diagnostic
• culture is usually too slow to help guide clinical
management.
• A negative viral culture does not exclude H1N1
influenza A infection.
• more chance of isolation in 1st 2 or 3 days of illness
62. Egg inoculation
• Amniotic cavity – 11 to 13 day old eggs
(6 eggs/specimen)
• Incubation at 35⁰C for 3 days
• Chilling, harvesting of amniotic and allantoic fluid
separately
• Tested for haemaggglutination with guinea pig and
fowl RBSs in parallel, at room temperature & at 4⁰C
63. • Influenza A – agglutinate only guinea pigs
• Influenza B – both guinea pig & fowl
• Influenza C - only fowl cells
• Inhibition of haemagg – specific viral antiserum
• Haemadsoption – addition of fresh guinea pig
RBC to cell culture
• Adv – no damage to the culture
64. Monkey Kidney or Baboon Kidney Cell cultures
• incubated without serum in presence of trypsin
which increases isolation
• Incubation at roller drums
• No cytopathic effects or focal enlarged granular cells
followed by sloughing, rapid progression
65. Shell vial culture
• Detection within 1 to 2 days
• 15 X 45mm vial having coverslip in the bottom
covered with growth medium and appropriate cell
monolayer
• specimen inoculated by low speed inoculation
• Coverslips are stained using virus specific
immunofluorescent conjugates
66.
67. Rapid Influenza Antigen Test
• Can distinguish between influenza A and B viruses.
• Can detect the HSI influenza A (h1n1) virus
• Not possible to differentiate from seasonal influenza
a viruses.
• Suboptimal sensitivity to detect seasonal influenza
viruses
• Negative rapid test could be a false negative
• Should not be assumed a final diagnostic test for
novel influenza A (H1N1) virus infection.
68. Interpretation Of Rapid Test
• There are several possibilities when a patient tests
positive for influenza A by rapid antigen test:
– The patient might have novel H1N1 virus infection
– The patient might have seasonal influenza A virus
infection or
– The patient might have a false positive test result
69. • In many new confirmed cases of novel H1N1 flu
infection and where community spread of H1N1 is
occurring - patients who test positive on a rapid
influenza diagnostic test can be treated empirically
with antiviral medications if clinically indicated
without further testing
70. Haemagglutination Inhibition tests
• Serial dilution of sera + Influenza virus suspension
containing 4 HA units + Fowl RBC
• Highest dilution of serum that inhibits
Haemagglutination - HI titre
• Disadv- Antihaemagglutinin antibodies are subtype
specific and hence it is necessary to use as antigen
the strain currently causing the infection
71. • Paired Sample for Serology Study at an interval of 14
days
• To demonstrate a four-fold or more rise in HSI
influenza A (H1N1) virus specific antibodies
72. Complement Fixation Test
• With RNP antigen
• Useful as antibodies formed only after infection
not immunisation with inactivated virus
Enzyme Neutralisation tests
• estimation of neuraminidase antibody
• Radioimmunodiffusion in agarose gel –
antibodies to RNP, haemagglutinin &
neuraminidase
74. Guiding principles
• Early implementation of infection control
precautions
• Prompt treatment to prevent severe illness
and death
• Early identification and follow up of persons at
risk
75. Infrastructure
• Isolation facilities
• If dedicated room not available – pts can be
cohorted in isolation wards with beds 1 meter
apart
• Man power – dedicate nurses, doctors and
paramedical staff
• Equipment's – separate
• Supplies – adequate supply of PPE ,
disinfectants and medications
76. SOP
• Reinforce standard infection control precaution i. e.
the person entering room must use high efficacy
mask, gown, goggles, gloves, cap and shoe cover.
• Restrict no. of visitors
• Provide antiviral prophylaxis to health care workers
• Dispose waste properly by labeling it as bio-hazard in
sealed impermeable bags
77. In-patient infection control measures
• Pt should be admitted directly to isolation facility and
continue to wear a 3 layer surgical mask
• HCW should wear PPE.
• Aerosol genetarting procedures should be performed with
N95 respirator on
• Perform hand hygiene
• Virus can survive for hrs to days – cleaning and disinfection
(Lysol, ethanol, Na hypochl.) of area, equipment,
contaminated surfaces daily
• Visual alerts should instructing patients and persons
accompanying them to practice respiratory hygiene
79. • Oseltamivir (brand name Tamiflu ®)- to both treat
and prevent influenza A and B virus infection in
people one year of age and older.
• Zanamivir (brand name Relenza ®)- to treat influenza
A and B virus infection in people 5 years and older
and to prevent influenza A and B virus infection in
people 5 years and older.
80.
81. • For adolescents (13 to17 years of age) and
adults the recommended oral dose is 75 mg
oseltamivir twice daily for 5 days
• children 6 to 12 months of age is 3 mg per kg
body weight twice daily for 5 days for
treatment
82. • >3 months to 12 months - 3 mg/kg twice daily
• >1 month to 3 months - 2.5 mg/kg twice daily
• 0 to 1 month - 2 mg/kg twice daily
• 15 kg or less - 30 mg orally twice a day for 5 days
• 15-23 kg - 45 mg orally twice a day for 5 days
• 24-40 kg- 60 mg orally twice a day for 5 days
• >40 kg - 75 mg orally twice a day for 5 days
83. Zanamivir
• Recommended dose for treatment of adults
and children from the age of 5 years (based is
two inhalations (2 x 5mg) twice daily for 5
days.
84. Supportive Therapy
• IV Fluids
• Parenteral nutrition
• Oxygen therapy/ventilatory support
• Antibiotics for secondary infection
• Vasopressors for shock
• Paracetamol or ibuprofen is prescribed for
fever,myalgia and headache.
85. Discharge policy
• 7 days after symptoms subside in adults and 14
days in children
• The family of patients discharged earlier should
be educated on personal hygiene and infection
control measures at home.
• Children should not attend school during this
period.
86. Antiviral Chemoprophylaxis
Given to
• All close contacts of suspected,probable and
confirmed cases.
• All health care personnel coming in contact with
suspected,probable or confirmed cases.
• Oseltamivir is the drug of choice.
• Prophylaxis should be provided till 10 days after last
exposure(maximum period of 6 weeks).
87. • Less than 15 kgs - 30mg OD
• 15-23 kg – 45 mg OD
• 24- less than 40kg -60 mg OD
• More than or equal to 40kg -75 mg OD
88. Dose For Infants
• Less than 3 mnths-not recommended unless
situation judged critical due to limited data on
use in this age group.
• 3 – 5 mnths- 20mg OD
• 6 – 11 mnths-25mg OD
89. • Close contacts of suspected , probable and confirmed
cases should be advised to remain at home for at least
7 days after the last contact with the case.
• Monitoring of fever should be done for at least 7 days.
• Prompt testing and hospitalization must be done when
symptoms are reported.
91. • Egg based vaccines – formalin inactivated
• Subunit vaccines – disrupted by detergents so
that they have only immunogenic HA & NA
subunits
• no bulk preparation
• Recombinant vaccines
92. • 1.5 million doses of vaccine to vaccinate selected population
among the high risk group.
• PANENZA, the pandemic vaccine procured from M/s Sanofi
Pasteur, France, is a split virus inactivated, non-adjuvanted
monovalent vaccine against pandemic Influenza
• The active ingredient containing antigen equivalent to:
• A/California/7/2009 (H1N1)v-like strain (NYMC X-179A) - 15
micrograms** per 0.5 ml dose
• propagated in eggs
• ** expressed in microgram haemagglutinin
93. • The other ingredients are: thiomersal (45
micrograms per 0.5 ml dose), sodium chloride,
potassium chloride, disodium phosphate dihydrate,
potassium dihydrogen phosphate, and water.
• suspension for injection in a multidose vial (10
doses of 0.5ml) - Pack of 10 vials. The suspension is
a colourless liquid, clear to opalescent
• One dose (0.5 ml) intra muscular
94. VaxiFlu-S
• Zydus Cadila
• Drug Controller General of India (DCGI) has gave
approval to Zydus Cadila to market the H1N1
(swine flu) vaccine.
• The egg-based, inactivated vaccine based on
conventional technology has been developed by
the group’s researchers at its Vaccine Technology
Centre (VTC) in Ahmedabad.
• Rs 350
• unveiled with health minister Ghulam Nabi Azad.
95. • It can only be used by people aged between
18-60 and can’t be used on small children or
pregnant women who are believed to be at
high risk of getting infected.
• The Swine Flu Vaccine, with a shelf life of a
year from date of manufacture, will provide
protection only for one year
96. • First indigenous intra-nasal vaccine was launched
in (nasovac)- serum institute of india, pune
• Launched on 15 july 2010 – mumbai
• Children over three years of age as well as for the
elderly
• Dose of 0.5ml directly to the nasal cavity
• Contraindicated -pregnant women, infants and
people with compromised immunity
