Influenza H1N1 Pandemic

8/14/2019 Influenza H1N1 Pandemic

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Human Influenza H1N1 Pandemic

Dr J KishoreMBBS, MD, PGCHFWM, PGDEE, MSc., MNAMS, FIPHA

Professor, Community Medicine, MAMC,

New Delhi


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Whats Influenza?

An acute RTI, caused by

Influenza virus, characterizedby sudden onset of:

Fever/ chills Headache, myalgia Sore throat

Cough Coryza Prostration

Range of symptoms differs by age Vomiting & diarrhea in children/

elderly Fever alone in infants

May be atypical in elderly

Serious complications canoccur among high-risk groups

Diarrhea

Coughing

Running Nose,

Sore Throat Lack of Appetite,

Headache

Nausea,

Vomiting

Fever
http://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svghttp://en.wikipedia.org/wiki/File:PD_Diagram_of_swine_flu_symptoms_EN.svg


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Influenza A: Important Feature

2 surface antigens:

Haemagglutinin (HA) Initiates infection following

attachment of virus tosusceptible cells

Neuraminidase (NA)Release of virus from

infected cell

16 H antigens (1-16) 9 N antigens (1-9)

Different combinations

Influenza Virus

HA NA


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Influenza A: Antigenic Variations

Antigenic drift:gradual antigenic change over a period; Involves point mutations in genes owing to selection pressureby immunity in host population

Responsible for frequent influenza epidemics; necessitatesreformulations of influenza vaccines.

Antigenic shift:sudden complete or major change; Results from genetic recombination of human with animal/

avian virus;

Leads to a novel subtype different from both parent viruses;

If novel subtype has sufficient genes from HI viruses whichmake it readily transmissible from person to person, it maycause pandemics;

Evidence suggests HI viruses responsible for last 3 pandemicscontained gene segments closely related to avian influenzaviruses.


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Species Infected by Influenza A Subtypes

H15,16H14

H13

H12

H11H10

H3

H2H1

H9

H8

H7

H6H5

H4

N9

N8

N7

N6N5

N3

N4

N2N1

All 16 H subtypes infect

birds;

most widespread epidemics

& all pandemics: H1N1,H2N2, H3N2


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Influenza Terminology - 1

Seasonal influenzaSeasonal influenzaAvian InfluenzaAvian Influenza Pandemic InfluenzaPandemic Influenza


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Seasonal influenzaSeasonal influenza:

occurs every year with gradual variations inprevious years virus surface proteins(antigenic drift); may give rise to epidemicsevery 2-3 years.

spreads around the world in seasonalepidemics, affecting 10 - 20% of total populationin general and >50% on close community;

annual epidemics thought to result in 3-5million cases of severe illness and 2.5 - 5 lakhdeaths

Avian InfluenzaAvian Influenza

Pandemic InfluenzaPandemic Influenza


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Seasonal influenzaSeasonal influenza

Avian InfluenzaAvian Influenza:

Primarily a disease of birds due to large groupof different influenza viruses;

Rarely jumps species and infects humans; An influenza pandemic happens when a newsubtype emerges that has not previouslycirculated in humans and is adapted to humanto human transmission.

Ultimately, is the source of new viruses inhumans causing pandemics.

Pandemic InfluenzaPandemic Influenza


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Seasonal influenzaSeasonal influenza

Avian InfluenzaAvian Influenza

Pandemic InfluenzaPandemic Influenza:

a worldwide surge in cases caused by theintroduction of a new type A surface protein(antigenic shift).


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Influenza Pandemics so far

A(H1N1) A(H2N2) A(H3N2)

1918: SpanishFlu

1957: Asian

Flu1968: Hong Kong

Flu

50 million

deaths1-4 million

deaths1-4 million

deaths

2004- 09:Current

outbreak

421 cases,257 death

Azerbaijan, China,

Cambodia, Djibouti,

Egypt, Indonesia,Iraq, Laos PDR,

Myanmar, Nigeria,

Pakistan, Thailand,

Turkey, Vietnam &

Bdesh ; till Apr. 2009

A(H5N1)


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Pre-requisites to Start InfluenzaPandemics

(i) Emergence of a novel virus towhich all are susceptible

(ii) New virus is able to replicate andcause disease in humans

(iii) New virus is transmitted efficiently

from human-to-human.

All criteria met


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Highly contagious acute

respiratory disease of pigs,caused by one of several

swine influenza A viruses:

Morbidity tends to be high

Low mortality (1-4%)

Although swine influenza

viruses (SIV) are normally

species specific, sometimescross species barrier to cause

disease in humans


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Swine influenza Present virus

Sometimes pigs can be infected with more than one virustype at a time, which can allow the genes from theseviruses to mix

This can result in an influenza virus containing genes

from a number of sources, called a "reassortant" virus The present virus: H1N1 virus with re-assorted

segments from: American swine,

Eurasian swine, Avian and

Human virus

Influenza A/H1N1 virus characterized in this outbreak

has not been previously detected in pigs/humans.


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How swine flu spread to human


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Re-assortment and Direct TransmissionRe-assortment and Direct Transmission

HumanHumanvirusvirus

ReassortantReassortant

virusvirus

Non-humanNon-human

virusvirus

Human to

human spread

Pigs

not involved

in

transmission


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Cases started around 18th March

And in short interval reached to epidemic form


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Evolution of Swine Influenza Pandemic

13th April 2009


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Evolution of Swine Influenza Pandemic

22 May

28 June

India-1

India 89


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CASES


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New Cases reported since last reporting period


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Public Health Concern

Number of affected countries with Influenza

H1N1 increasing

Number of human cases of influenza H1N1

increasing

The majority of the human population has no

immunity

Potential to further mutate to a lethal novelinfluenza virus


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WHO Alert

Current situation constitutes a PHEIC(public health emergency of internationalconcern).

WHO has declared H1N1 Pandemic, i.e,

Phase 6 implying widespread humantransmission.

Containment of the outbreak is notfeasible.

The current focus should be on mitigationmeasures.

Not to close borders and not to restrict

international travel ???


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Disease Transmission

H-2-H transmission mainly occursthrough direct droplet transmission(usually within 6 feet).

Same way as seasonal flu - mainly

through coughing or sneezing People may be infected by touchingsomething with flu viruses on it andthen touching their mouth, nose oreyes (moist mucous membranes)

before washing their hands. Infected people can infect others

beginning 1 day before and up to7 or more days after symptoms

develop.


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Symptoms and signs of H1N1 in humans?

Similar symptoms as of human seasonalinfluenza.

Fever ( 38 C), AND

cough and sore throat

Body aches, headache, chills, and fatigue or

lack of appetite.

Some people with H1N1 have reported runny

nose, nausea, vomiting, and diarrhea.


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Case Definition: Influenza A(H1N1) virus infection

Suspected case is defined as a personwith acute febrile respiratory illness (fever 380C) with onset:

within 7 days of close contact with a person whois a confirmed case of swine influenza A (H1N1)virus infection, or

within 7 days of travel to community where

there are one or more confirmed swine influenzaA(H1N1) cases, or resides in a community where there are one or

more confirmed swine influenza cases.


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Probable case: defined as a person with an acute febrilerespiratory illness who is:

positive for influenza A, but unsubtypable for H1 by

influenza RT-PCR or reagents used to detect seasonalinfluenza virus infection, or

positive for influenza A by an influenza rapid test or aninfluenza immuno-fluorescence assay (IFA) plus meets

criteria for a suspected case individual with a clinically compatible illness who died

of an unexplained acute respiratory illness who isconsidered to be epidemiologically linked to a probable

or confirmed case.

Case Definition: Influenza A

(H1N1) virus infection


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Confirmed case: defined as 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:

Real Time PCRviral culture

Four-fold rise in swine influenza A (H1N1) virus

specific neutralizing antibodies.

Case Definition: Influenza A

(H1N1) virus infection


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If swine flu is suspected, clinicians should obtain aNasopharyngeal or throat swab for swine

influenza testing and place it in a refrigerator (nota freezer) but transport within 24 hours if not thenstore at 70 degree C.

Once collected, the clinician should contacttheir state or local health department tofacilitate transport and timely diagnosis at astate public health laboratory


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he guiding principles of treatment are:

arly implementation of infection control precautions

o minimize nosocomical / household spread of disease.

rompt treatment to prevent severe illness & death.

arly identification and follow up of persons at risk.

nfrastructure / manpower / material support

nfrastructure & Manpower

solation facilities: if dedicated isolation room is not available then


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Standard Operating Procedures

Reinforce standard infection control

precautions i.e. all those entering the roommust use high efficiency masks, gowns,

goggles, gloves, cap and shoe cover.

Restrict number of visitors and provide themwith PPE.

Provide antiviral prophylaxis to health care

personnel managing the case and ask them to

monitor their own health twice a day.

Dispose waste properly by placing it in sealed

impermeable bags labeled as Bio- Hazard.


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Steps of Hand Washing Technique


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Clinical Management

Pharmaceutical Interventions

Viruses so far characterized have been sensitive tooseltamivir & zanamivir; resistant to amantadine &rimantadine

Treatment: Oseltamivir 75 mg twice daily for 5 days

Chemoprophylaxis: Close contacts of a confirmed case

Health care personnel coming in contact with confirmed case

Oseltamivir 75 mg once daily for 10 days

Vaccine:Not available as of now; 4-6 mths later


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Oseltamivir Recommended doses

Body weight RecommendedDose

< 15 kg (< 33 lb) 30 mg

> 15 kg 23 kg (> 33

lb 51 lb)

45 mg

> 23 kg 40 kg (> 51lb 88 lb)

60 mg

> 40 kg (> 88 lb) 75 mg

Supportive Therapy


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Supportive Therapy

Fluid

Parentral nutrition.

Oxygen therapy/ ventilatory support.

Antibiotics for secondary infection.

Vasopressors for shock.

Paracetamol or ibuprofen is prescribed for fever, myalgia and

headache. Patient is advised to drink plenty of fluids. For sore

throat, short course of topical decongestants, saline nasal drops,

throat lozenges and steam inhalation may be beneficial.

Salicylate / aspirin is strictly contra-indicated (Reyes syndrome).

The suspected cases would be constantly monitored for clinical /

radiological evidence of lower respiratory tract infection and for

hypoxia (respiratory rate, oxygen saturation, level ofconsciousness .


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- Maintain airway, breathing and circulation (ABC);

- Maintain hydration, electrolyte balance and nutrition.- If the laboratory reports are negative, the patient would

be discharged after giving full course of oseltamivir.-Immunomodulating drugs has not been found to be

beneficial in treatment of ARDS or sepsis associated

multi organ failure.

-Low dose corticosteroids (Hydrocortisone 200-400 mg/day) may be useful in persisting septic shock (SBP < 90).

- No antibiotics if no pneumonia.

- Antibacterial agents should be administered, irequired, as per locally accepted clinical practice

guidelines. Patient on mechanical ventilation should be

administered antibiotics prophylactically to prevent

hospital associated infections.

T f t ti k


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Surgical masks Easily available and commonly used for routine surgical and

examination procedures

High-filtration respiratory mask Special microstructure filter disc to flush out particles bigger than 0.3

micron. These masks are further classified: oil proof oil resistant not resistant to oil

The more a mask is resistant to oil, the better it is The masks have numbers beside them that indicate their filtration

efficiency. For example, a N95 mask has 95% efficiency in filtering outparticles greater than 0.3 micron under normal rate of respiration.

The next generation of masks use Nano-technology which arecapable of blocking particles as small as 0.027 micron.

Types of protective masks

N Ph l i l M


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Complete Personal Protective Equipment for Infectious diseases

Non-Pharmacological Measures

Non-Pharmacological Measures


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Respiratory etiquettes

Non Pharmacological Measures


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Community measures

Social distancing

measures (at onset ofoutbreak)

Avoiding crowdedplaces

Border/ Port / airportControl

Infection controlpractices

Risk communication


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Actions taken by Ministry of Health

CoS, Inter Ministerial Task Force ( IMTF)and Joint Monitoring Group (JMG)monitoring the situation.

Enhanced surveillance at all InternationalAirports to detect entry of disease into India atthe earliest and contain the same.

Travel advisory issued to defer non-essential

travel to the affected countries.

Tracking of persons travelled to India fromaffected countries.


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Actions taken by Ministry of Health

States alerted to heighten the level ofpreparedness and action.

IDSP focal points in States to look for and report

clusters of ILI and that of pneumonia Central and State RRTs alerted to investigate and

manage outbreaks.

Identified labs at NICD, Delhi and NIV, Punebeside all regional centers BSL2 Laboratories to

test clinical samples of the novel virus.


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Actions taken by Ministry of Health-3

Guidance issued to States on clinical management,infection control practices, laboratory support.

Guidelines also available on MOHFW web site.

Supply of Oseltamivir to states reporting cases. Supply of PPE to states reporting cases and other

potential states.

Medical supplies are decentralized

IEC activities initiated in print and visual media.

24X7 Control room

Daily press briefing by identified authority.


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Actions by State Governments

Travel advisory issued by Central Government be re-

emphasized.

Assist MOHFW in tracking of persons travelled to India fromaffected countries.

Websites:www.mohfw.nic.in

www.nicd.nic.in
http://www.mohfw.nic.in/http://www.mohfw.nic.in/http://www.nicd.nic.in/http://www.nicd.nic.in/http://www.nicd.nic.in/http://www.nicd.nic.in/http://www.nicd.nic.in/http://www.nicd.nic.in/http://www.mohfw.nic.in/http://www.mohfw.nic.in/http://www.mohfw.nic.in/http://www.mohfw.nic.in/http://www.mohfw.nic.in/


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Actions by State Governments

IEC activities has been initiated using printand visual media.

Messages suggesting Dos & Donts to be re-

emphasised Nodal person for media briefing to be

identified and communicated to MOHFW. He

should be in constant touch with Director(M&C), 99999-96104.

Press briefing by designated authority only.

D d D Ed i h P bli


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Dos and Dont: Educating the Public

Covering nose and mouth with a tissue when coughing orsneezingDispose the tissue in the trash after use.

Handwashing with soap and waterEspecially aftercoughing or sneezing.

Cleaning hands with alcohol-based hand cleaners

Avoiding close contact with sick people

Avoiding touching eyes, nose or mouth with unwashedhands

If sick with influenza, staying home from work or school

and limit contact with others to keep from infecting them Staying away: from poultry. Keep them secure in cages.

Keep children out of reach. Wash hands if in contact withpoultry or poultry products.

Remain healthy by adequate sleep and balanced diet


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References

CDC USA website

Ministry of Health & Family Welfare, Govt. ofIndia,

National Institute of Communicable Diseases,Government of India

WHO website

Kishore J A Dictionary of Public Health (2nd Ed).New Delhi: Century Publications 2007


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Documents

Influenza H1N1 Pandemic