IMA Expert committee on

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SWINE FLU
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Swine Influenza

• Swine Influenza (swine flu) is a respiratory
  disease of pigs caused by type A influenza virus.
• Causes outbreaks of influenza in pigs and low
  death rates in pigs.
• Pigs are infected with avian, human and swine
  influenza viruses and hence known to be a mixing
  vessel.

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Influenza Virus Types A, B, and C
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Swine Flu in Humans

• Swine viruses normally do no infect humans
• Influenza A (H1N1) (earlier know as swine flu)
  is a new influenza virus causing illness in
  people.
• Initially thought to have gene segments from the
  swine, avian and human flu virus genes.
• Subsequent analysis suggested it was a
  reassortment of just two strains, both found in
  swine.
• The scientists calls this a quadruple
  reassortant virus and hence this new (novel)
  virus is christened Influenza-A (H1N1) virus.

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Novel Influenza A (H1N1)

• First detected in Mexico in April, 2009, it has
  spread to many countries in the World.
• The H1N1 form of swine flu is one of the
  descendants of the strain that caused the 1918
  flu pandemic
• The Influenza A H1N1 virus characterized in this
  outbreak have not been previously detected in
  pigs or humans.
• This virus is sensitive to Oseltamivir, but
  resistant to both Amantidine Rimantidine.

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Influenza Virus
Influenza Virus
HA
NA
The viruses are 80120 nanometres in diameter
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Influenza Pandemics
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Epidemiological prerequisites to start Influenza
Pandemics

• Emergence of a novel virus to which all are
  susceptible.
• New virus is able to replicate and cause
  diseases in humans.
• New virus is transmitted efficiently from human
  to human.
• All criteria met

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Influenza Pandemics Global Health Implications

• Disease and Death.
• About 500 million are expected to fall ill.
• A significant proportion will require medical
  care.
• 6.4 - 28 hospitalizations.
• 2-7 Million deaths, even with low case fatality
  rate of 0.6

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Public Health Concern

• Number of affected countries with Influenza A
  H1N1 is increasing.
• Number of human cases also is increasing.
• Majority of human population has no immunity.
• Potential to further mutate to a lethal novel
  Influenza virus.

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The current WHO phase of pandemic alert is 6.
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Transmission

• The secondary attack rate of the strain causing
  this pandemic is estimated to be 22 to 33
  percent, compared with 5 to 15 percent for
  seasonal influenza
• Transmission to humans
• People who work with poultry and swine,
  veterinarians and meat processing workers, are at
  increased risk of zoonotic infection with
  influenza virus endemic in these animals.
• Zoonosis and reassortment can occur in human
  hosts
• .

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Re-assortment and Direct Transmission
Non-human virus
Human virus
Reassortant virus
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Transmission

• Virus is transmitted in ways similar to other
  influenza viruses.
• Primarily through large-particle respiratory
  droplet
• This requires close contact between source and
  recipient persons because droplets do not remain
  suspended in the air and generally travel only a
  short distance (lt 6 feet).
• Contact with contaminated surfaces is another
  possible source of transmission
• All respiratory secretions and bodily fluids
  (include diarrhoeal stool) of novel influenza A
  (H1N1) cases should be considered potentially
  infectious.

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Case Definitions

• A confirmed case of H1N1 infection is defined as
  a person with an acute febrile respiratory
  illness with laboratory confirmed H1N1 infection
  at CDC/ Reference Lab by one or more of the
  following tests
• real-time RT-PCR
• viral culture
• Four-fold rise in swine influenza A (H1N1) virus
  specific neutralizing antibodies.
• A probable case of H1N1 infection is defined as a
  person with an acute febrile respiratory illness
  who is positive for influenza A, but negative for
  H1 and H3 by influenza RT-PCR

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Case Definitions

• A suspected case of H1N1 infection is defined as
  a person with acute febrile respiratory illness
  with onset
• within 7 days of close contact with a person who
  is a confirmed case of H1N1 infection, or
• within 7 days of travel to a community where
  there are one or more confirmed cases of H1N1
  infection, or
• resides in a community where there are one or
  more confirmed cases of H1N1 infection.

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Case Definitions

• Acute febrile respiratory illness is defined as a
  measured temperature 100 degrees Fahrenheit and
  recent onset of at least one of the following
  rhinorrhea or nasal congestion, sore throat, or
  cough.
• Influenza Like Illness (ILI) is defined as
  sudden onset of fever over 38 degree C cough or
  sore throat an absence of other diagnosis.

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Severe Acute respiratory Infection (SARI)

• For those above 5 Yrs.-WHO def.
• Sudden onset of fever over 38 degree C
• Cough or sore throat
• Shortness of breath or difficulty in breathing
  and
• Requiring hospitalization.
• For children below five years
• Clinically suspected of having pneumonia or
  severe / very severe pneumonia.

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Signs and Symptoms

• Incubation period The estimated incubation
  period is unknown and could range from 1-7 days,
  and more likely 1-4 days.
• Infectious period The duration of shedding with
  novel influenza A (H1N1) virus is unknown.
• The estimated duration of viral shedding is based
  upon seasonal influenza virus infection.
• In general, persons with novel influenza A (H1N1)
  virus infection should be considered potentially
  infectious from one day before to 7 days
  following illness onset. Children, especially
  younger children, might be infectious for up to
  10 days.

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• These symptoms are not specific to swine flu
  differential diagnosis of probable swine flu
  requires not only symptoms but also a high
  likelihood of swine flu due to the person's
  recent history.
• CDC advise- 2009 Swine flu outbreak in USA,
• "consider swine influenza infection in the
  differential diagnosis of patients with acute
  febrile respiratory illness who have either been
  in contact with persons with confirmed swine flu,
  or who were in one of the five U.S. states that
  have reported swine flu cases or in Mexico during
  the 7 days preceding their illness onset.
• A diagnosis of confirmed swine flu requires
  laboratory testing of a respiratory sample (a
  simple nose and throat swab).

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Complications

• Upper respiratory tract disease-sinusitis, otitis
  media, croup
• Lower respiratory tract disease- pneumonia,
  bronchiolitis, status asthmaticus
• Cardiac myocarditis, pericarditis
• Musculoskeletal- myositis, rhabdomyolysis
• Neurologic- acute and post-infectious
  encephalopathy, encephalitis, febrile seizures,
  status epilepticus
• Toxic shock syndrome
• Secondary bacterial pneumonia with or without
  sepsis.

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Groups at high risk for complications

• Children lt 5 years old
• Persons aged 65 years or older
• Children and adolescents receiving long-term
  aspirin therapy and who might be at risk for
  experiencing Reye syndrome after influenza virus
  infection
• Pregnant women
• Adults and children with chronic pulmonary,
  cardiovascular, hepatic, hematological,
  neurologic, neuromuscular, or metabolic disorders
• Adults and children who have immunosuppression
  (including immunosuppression caused by
  medications or by HIV)
• Residents of nursing homes / chronic-care
  facilities

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• Diagnosis

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Specimen Collection

• Children shed high titres of virus
• Analytical sensitivity of assay depends
  on specimen type
• Timing of specimen collection

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Specimen Collection Kit

• Collection vials with VTM
• Polyester fiber-tipped applicators
• Sterile saline
• (0,85 NaCl)
• Sputum or mucus trap
• Tongue depressors
• Specimen collection cups or Petri dishes
• Transfer pipettes

• Secondary container
• Ice packs
• Items for blood collection
• Personal protective equipment
• Field collection forms
• A pen or marker for labeling samples

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What to Collect

• From an Ambulatory patient
• Nasal swab and
• Throat swab
• Can be collected into the same VTM
• From an Intubated patient
• Lower respiratory aspirate
• Other specimens
• Posterior pharyngeal swabs
• Nasal washes
• Acute and convalescent serum

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Serological Samples

• Paired serum samples are most useful
• Acute sample Within 7 days after symptom onset
• Convalescent sample More than 21 days after
  symptom onset at (an interval of 14 days. )

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How to Store Specimens For specimens in VTM

• Transport to laboratory as soon as possible
• Store specimens at 4 C before and during
  transportation
• within 48 hours
• Store specimens at -70 C beyond 48 hours
• Do not store in standard freezer keep on ice
  or in
• refrigerator
• Avoid freeze-thaw cycles -Better to keep on ice
  for a week than to have repeat freeze and thaw

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Lab facilities in India

• NIV - Pune
• NICD - Delhi

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Prevention

• Prevention of swine influenza has three
  components
• prevention in swine,
• prevention of transmission to humans,
• prevention of its spread among humans.

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Prevention in humans

• Swine can be infected by both avian and human
  influenza strains of influenza, and therefore are
  hosts where the antigenic shift can occur that
  create new influenza strains.
• The use of vaccines on swine to prevent their
  infection is a major method of limiting swine to
  human transmission.
• Risk factors that may contribute to
  swine-to-human transmission include smoking and
  not wearing gloves when working with sick animals

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Prevention of human to human transmission

• Influenza spreads between humans through coughing
  or sneezing and people touching something with
  the virus on it and then touching their own nose
  or mouth.
• Swine flu cannot be spread by pork products,
  since the virus is not transmitted through food.
• The swine flu in humans is most contagious during
  the first five days of the illness although some
  people, most commonly children, can remain
  contagious for up to ten days.
• Diagnosis can be made by sending a specimen,
  collected during the first five days for
  analysis.

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Preventing Transmission in the Community

• Respiratory etiquette
• Cover nose / mouth when coughing or sneezing
• Hand washing!

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• Social Distancing Staying away from other people
  who might be infected - include avoiding large
  gatherings, spreading out a little at work, or
  perhaps staying home and lying low if an
  infection is spreading in a community.
• Public Health and other responsible authorities
  have action plans which may request or require
  social distancing actions depending on the
  severity of the outbreak.

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• Recommendations to prevent spread of the virus
  among humans include using standard infection
  control against influenza.
• This includes frequent washing of hands with soap
  and water or with alcohol-based hand sanitizers,
  especially after being out in public.
• Chance of transmission is also reduced by
  disinfecting household surfaces, which can be
  done effectively with a diluted chlorine bleach
  solution.
• Although the current trivalent influenza vaccine
  is unlikely to provide protection against the new
  2009 H1N1 strain, vaccines against the new strain
  are being developed.

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Steps to be taken for Infection Control of Ill
Persons in a Healthcare Setting

• Patients with suspected or confirmed case status
  should be placed in a single patient room with
  the door kept closed.
• If available, an airborne infection isolation
  room (AIIR) with negative pressure air handling
  with 6 to 12 air changes per hour can be used.
• Air can be exhausted directly outside or be
  re-circulated after filtration.
• For suctioning, bronchoscopy, or intubation, use
  a procedure room with negative pressure air
  handling.

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Personal Protection Equipments

• Goggles N-95
  Mask Gloves
• Gown (must for lab work) Triple layer Mask
  Shoe covers

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• Correct procedure for applying PPE in the
  following order
• Follow thorough hand wash
• Wear the coverall.
• Wear the goggles/ shoe cover/and head cover in
  that order.
• Wear face mask
• Wear gloves
• The masks should be changed after every six to
  eight hours.
• Remove PPE in the following order
• Remove gown (place in rubbish bin).
• Remove gloves (peel from hand and discard into
  rubbish bin).
• Use alcohol-based hand-rub or wash hands with
  soap and water.
• Remove cap and face shield (place cap in bin and
  if reusable place face shield in container for
  decontamination).
• Remove mask - by grasping elastic behind ears
  do not touch front of mask
• Use alcohol-based hand-rub or wash hands with
  soap and water.
• Leave the room.
• Once outside room use alcohol hand-rub again or
  wash hands with soap and water.

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Droplet Precautions

• Taken in addition to Standard Precautions
• Wear surgical mask within 1 meter of patient
• Wear face shield or goggles within 1 meter of
  patient
• Place patients in single rooms or cohort 1 meter
  apart
• Limit patient movement within facility
• Patient wears mask when outside of room

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Treatment

• Antiviral drugs can make the illness milder and
  make the patient feel better 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).
• The U.S. CDC recommends the use of Tamiflu
  (Oseltamivir) or Relenza (Zanamivir) for the
  treatment and/or prevention of infection with
  swine influenza viruses
• However, the majority of people infected with the
  virus make a full recovery without requiring
  medical attention or antiviral drugs.
• The virus isolates in the 2009 outbreak have
  been found resistant to amantadine and rimantadine

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Clinical Management

• Infection control
• Isolate the patient
• Implement infection control precautions
• PPE for HCW and family members
• Supportive care (ICU)
• Pulmonary administer oxygen mechanical
  ventilation for respiratory failure
• Treatment
• Antiviral medications (oseltamivir)
• Corticosteroid treatment is not recommended

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WHO. NEJM 20053531374-85 WHO Rapid advance
guideline, June 2006
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Pharmacotherapy

• Oseltamivir is the WHO recommended drug and the
  only one available with the Government for
  treating Influenza H1N1.
• The drug would have application in three
  scenarios
• For individual treatment
• The recommended dose is 75 mg twice daily for
  adults. For adolescents and pediatric age group,
  the dosage is based on body weight and
  recommended schedule is
• For weight lt15kg 30 mg twice daily for 5
  days
• 15-23kg 45 mg twice daily
  for 5 days
• 24-lt40kg 60 mg twice daily for
  5 days
• gt40kg 75 mg twice daily
  for 5 day

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• 2. For children below one year and
  for pregnant women
• the administration of oseltamivir would be
  based on risk benefit analysis. The recommended
  dose for children less than one year is
• Age lt3 months 12 mg twice daily
• Age 3 to 5 months 20 mg twice daily
• Age 6 to 11 months 25 mg twice daily
• 3. Supportive therapy For secondary
  complications including bacterial infections,
  appropriate treatment may be provided as
  indicated.

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Other Treatment

• IV Fluids.
• Parentral nutrition.
• Oxygen therapy/ ventilatory support.
• Antibiotics for secondary infection- Prophylaxis
  avoided
• Vasopressors for shock.
• Paracetamol or ibuprofen is prescribed for fever,
  myalgia and headache.
• Patient is advised to drink plenty of fluids.
• Avoid smoking.
• 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
  in any influenza patient due to its potential to
  cause Reyes syndrome.
• Monitor for clinical / radiological evidence of
  lower respiratory tract infection and for
  hypoxia.

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Chemoprophylaxis

• All close contacts of suspected, probable and
  confirmed cases. Close contacts include household
  /social contacts, family members, workplace or
  school contacts, fellow travelers etc.
• 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)
• For infants lt 3 months not recommended unless
  situation judged critical due to limited data on
  use in this age group

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Discharge Policy

• Adult patients should be discharged 7 days after
  symptoms have subsided.
• Children should be discharged 14 days after
  symptoms have subsided.
• 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.

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Influenza Vaccine

• Seasonal Influenza vaccine does not protect
  against Novel H1N1 infection. But in areas where
  seasonal influenza is circulating this can be
  given in unvaccinated patients.
• Making new influenza vaccines ready to immunize
  people generally takes five to six months after
  first identification of the pandemic virus.

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• The very first doses of influenza A (H1N1)
  vaccine usable to immunize people, from one or
  more manufacturers, are expected as early as
  September 2009
• Based on a global survey made by WHO on 15 May
  2009, a maximum of 4.9 billion doses potentially
  could be produced in 12 months
• Whether one or two doses of the vaccine will be
  needed to achieve protection.
• Strategic Advisory Group of Experts (SAGE) on
  Immunization SAGE recommended that health care
  workers worldwide should be immunized as a first
  priority

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• Need to Panic???

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Thank You