Influenza A
(H1N1)
Directorate of Public Health and
Preventive Medicine, Tamilnadu
October 2018
Influenza A (H1N1)
(Swine flu)
• Swine flu is a respiratory disease of pigs
caused by Type A Influenza virus that
causes regular outbreaks in pigs
• Swine flu viruses have been reported to
spread from person-to-person, however
transmission was limited
• The last pandemic started in Mexico in
2009 and now declared as seasonal
influenza
Pandemics of
Recorded human pandemic influenza
(early sub-types inferred)
influenza
H2N2 H2N2
H1N1 H1N1
Pandemic
H3N8 H3N2 H1N1
1895 1905 1915 1925 1955 1965 1975 1985 1995 2005 2010 2015
1889 1900 1918 1957 1968 2009
Russian Old Hong Kong Spanish Asian Hong Kong Pandemic
influenza influenza influenza influenza influenza influenza
H2N2 H3N8 H1N1 H2N2 H3N2 H1N1
Recorded new avian influenzas H9* 1999
H5 1997 2003
H7 1980 1996 2002
1955 1965 1975 1985 1995 2005
3
Reproduced and adapted (2009) with permission of Dr Masato Tashiro, Director, Center for Influenza Virus Research,
National Institute of Infectious Diseases (NIID), Japan. Animated slide: Press space bar
Phases of Pandemic Influenza
Influenza A (H1N1)
(Swine flu)
• Swine flu is a respiratory disease of pigs caused
by Type A Influenza virus that causes regular
outbreaks in pigs
• Swine flu viruses have been reported to
spread from person-to-person, however
transmission was limited
• During pandemic and post pandemic situation
widespread human to human infection occurs
What is Influenza A (H1N1) ?
• Viral infection.
• Genetic mixing of three different
viruses
• Highly susceptible to anti viral drug
Oseltamivir
Situation since 2009
• Global
– First case reported on 18th March 2009
– WHO declared Post Pandemic – June 2010
• India
• Pandemic Phase – May 2009 to Dec 2010
• Post Pandemic Phase – Jan 2011 – Dec 2014
• Circulating as Seasonal Influenza
• Tamil Nadu
• First case : 1st May 2009 & Declined in 2011
• Cases continue to report sporadically
Epidemiology of AH1N1
Case Definition*
A suspected case
Acute febrile respiratory illness who
• Develops symptoms within seven days of close
contact with a person who is a confirmed case of
H1N1 influenza A virus infection or
• Develops symptoms within seven days of travel or
resides in a community where there are one or
more confirmed A H1N1 influenza cases
* CDC definition
Case Definition
• A probable case:
Acute febrile respiratory illness who is positive
for influenza A, but negative for H1 and H3 by
RT-PCR
• A confirmed case
Acute febrile respiratory illness with
laboratory-confirmed H1N1 influenza A virus
detection by real-time reverse transcriptase
PCR (RT-PCR) or culture.
Guidelines for categorization of
Seasonal Influenza cases and Management
Category – A
Patients with mild fever plus cough /
sore throat with or without body
Symptomatology ache, headache, diarrhoea and
vomiting
Drug Do not require Oseltamivir
Lab Test No testing for Influenza is required
• Home isolation
Management • Symptomatic treatment
Category – B
(i) Signs and symptoms of Category – A with high
grade fever and severe sore throat
(ii) Signs and symptoms of Category – A with one/
more of the following
•Children with predisposing factors
Symptomatology •Pregnant women
•Persons aged >65 years
•Patients with lung, heart, liver, kidney diseases,
Diabetes, Blood disorders, HIV/AIDS
•Patients on steroid therapy
Drug Require Oseltamivir
Lab Test No testing for Influenza is required
• Home isolation
Management • Broad spectrum antibiotics
Category – C
Signs and symptoms of Category – A & B with one or
more of the following:
•Breathlessness
•Chest pain
•Drowsiness
Symptomatology •Fall in Blood Pressure
•Sputum mixed with blood
•Children with ILI who had a severe disease as
manifested by the red flag signs
•Worsening of underlying chronic conditions
Drug Require Oseltamivir
Lab Test Require testing for Influenza
Management • Immediate hospitalization & Treatment
Categorization of Seasonal Influenza cases - Guidelines
Category – A Category – B Category – C
Patients with mild fever (i) Signs and symptoms of Signs and symptoms of
plus cough / sore throat Category – A with high Category – A & B with one
with or without body ache, grade fever and severe or more of the following:
headache, diarrhoea and sore throat •Breathlessness
vomiting (ii) Signs and symptoms of •Chest pain
Category – A with one/ •Drowsiness
more of the following •Fall in Blood Pressure
•Children with •Sputum mixed with blood
predisposing factors •Children with ILI who had
•Pregnant women a severe disease as
•Persons aged >65 years manifested by the red flag
•Patients with lung, heart, signs
liver, kidney diseases, •Worsening of underlying
Diabetes, Blood disorders, chronic conditions
HIV/AIDS
•Patients on steroid
therapy
Do not require Oseltamivir Require Oseltamivir Require Oseltamivir
No testing for Influenza is No testing for Influenza is Require testing for
required required Influenza
• Home isolation • Home isolation • Immediate
• Symptomatic treatment • Broad spectrum hospitalization &
Mode of transmission
• People become infected by touching
something with live flu viruses on it and then
touching their mouth or nose
(More than 80%)
• Viruses are spread from person to person by
droplet through coughing or sneezing of
people with influenza.
Communicability
• From one day before to 7 days after the
onset of symptoms.
• If illness persists for more than 7 days,
communicability may persist.
• Children, especially younger children, might
potentially be contagious for longer periods.
Clinical features
Vomiting or diarrhea (not typical for influenza but reported by
recent cases of swine influenza infection)
Other Manifestations
• Tachycardia
• Tachypnoea
• Low O2 sat.
• Hypotension
• Cyanosis
• Acute myocarditis
• Cardiopulmonary arrest
High Risk Group
• Asthma • Chronic liver disease
• Pregnancy • Chronic neurological
• Age above 65 Years disease
• Children under five • Immunosuppressant
years (whether caused by
• Chronic lung disease disease or treatment)
• Chronic heart disease • Diabetes mellitus
• Chronic kidney disease • Obesity
Investigations
• Routine investigations for evaluation and
management of symptoms
– Hematological, bio chemical, radiological and micro biological tests
• Confirmation of influenza
– Real Time RT – PCR
– Isolation of virus in culture
– Four fold rise in virus specific neutralizing antibodies
Case Management
• Prompt treatment to prevent severe
illness and death
– Supportive treatment (Antipyretics, antibiotics, IV fluids,
Oxygen therapy, nutrition, saline gorgling, mucolytics
etc)
– Specific anti viral treatment (Oseltamivir)
Antiviral treatment
• Oseltamivir (Tami flu) is the drug of choice for
treatment and chemoprophylaxis.
• Available in capsule (75 mg, 45 mg and 30 mg)
and syrup form (60 ml bottle = 12 mg per ml)
• For treatment, antiviral drugs work best if
started soon after getting sick
• Reduces the duration of virus excretion and the
severity of illness
Antiviral treatment for cases
• Duration of treatment: 5 days BD
• Dosage schedule
Weight Dosage
<15 kg 30 mg BD 5Days
15-23 kg 45 mg BD 5Days
24 to <40kg 60 mg BD 5Days
>40 kg 75 mg BD 5Days
Antiviral treatment for
cases-Infants
• Duration of treatment: 5 days BD
• Available as oral suspension
• Dosage schedule
Months Dosage
<3 months 12mg BD 5Days
3-5 months 20mg BD 5Days
6-11 months 25mg BD 5Days
Contact tracing and
chemoprophylaxis
• Powerful public health intervention to
interrupt the transmission
• All contacts of confirmed cases are to be
administered with Oseltamivir (Tami flu)
irrespective of whether they have
symptoms or not
Antiviral dosage for
chemoprophylaxis
• Duration of treatment: 10 days OD
• Dosage schedule
Weight Dosage
<15 kg 30 mg OD 10 Days
15-23kg 45mg OD 10 Days
24to<40kg 60mg OD 10 Days
>40 kg 75mg OD 10 Days
Antiviral dosage for
chemoprophylaxis -infants
• Duration of treatment: 10 days OD
• Chemoprophylaxis not recommended for children
below 3 months generally
• Dosage schedule
Months Dosage
3-5 months 20 mg OD 10 Days
6-11 months 25 mg OD 10 Days
Guidelines for hand
washing in Health Care
Settings
• Use surgical spirit (70% alcohol or
more)
• Wash hands before and after
seeing every patient
• Discord basins with antiseptic
lotions for handwashing.
Note: Hand wash should be done
only in running water
Hand Hygiene
Hand Hygiene
Hand Hygiene - Video
IEC Material
Guidelines for schools
• Daily screening
• Students / teacher with flu like condition
should be sent to a doctor
• Home isolation/ admission in isolation ward
as per category
• Disinfect the class rooms before the
commencement of next class (Floor with 5%
Lysol and other surfaces including desk
with surgical spirit)
Guidelines for cinema
theatres
• Disinfect the theatre before the
commencement of next show
– Floor with 5% Lysol or 1% hypochlorite
solution
• Seats, ticket counters and other surfaces
with surgical spirit
Guidelines for marriage
halls and other
community halls
• Disinfect the hall before the commencement
of next function
– Floor with 5% Lysol or 1% hypochlorite solution
• Seats and other surfaces with surgical spirit
Guidelines for lodging
houses
• Disinfect the room before allotting to
the next guest
– Floor with 5% Lysol or hypochlorite
solution
– Seats, teapoy, TV remote, door handles
and other surfaces with surgical spirit
Guidelines for Public
Transport
• Disinfect the vehicle particularly the
areas touched by hands at the end of
every trip
– Floor with 5% Lysol
– Seats and other surfaces with surgical spirit
Guidelines for Public
Places
• Improve general cleanliness
– Floor with 5% Lysol or hypochlorite solution
– Seats and other surfaces with surgical
spirit
• Liberal use of disinfectants
What should I do?
• First and most important: wash your hands
• Practice cough etiquette
• Avoid touching surfaces that may be
contaminated with the flu virus.
• Avoid close contact with people having flu
like illness
What should I do?
• Staying at home if you have flu like
symptoms
• Educating school children and staff, advising
avoidance of mass gatherings
• Avoid crowded places, avoid hand shaking
• Avoid picnics
