INFLUENZA VIRUS

1
INFLUENZA VIRUS

• INFLUENZA VIRUS
• CDC WEBSITE
• http//www.cdc.gov/ncidod/diseases/flu/fluinfo.htm

2

• Swine Influenza A (H1N1) Infection in Two
  Children --- Southern California, March--April
  2009
• On April 17, 2009, CDC determined that two cases
  of febrile respiratory illness occurring in
  children who resided in adjacent counties in
  southern California were caused by infection with
  a swine influenza A (H1N1) virus. The viruses
  from the two cases are closely related
  genetically, resistant to amantadine and
  rimantadine, and contain a unique combination of
  gene segments that previously has not been
  reported among swine or human influenza viruses
  in the United States or elsewhere. Neither child
  had contact with pigs the source of the
  infection is unknown. Investigations to identify
  the source of infection and to determine whether
  additional persons have been ill from infection
  with similar swine influenza viruses are ongoing.
  Although this is not a new subtype of influenza A
  in humans, concern exists that this new strain of
  swine influenza A (H1N1) is substantially
  different from human influenza A (H1N1) viruses,
  that a large proportion of the population might
  be susceptible to infection, and that the
  seasonal influenza vaccine H1N1 strain might not
  provide protection. The lack of known exposure to
  pigs in the two cases increases the possibility
  that human-to-human transmission of this new
  influenza virus has occurred. Clinicians should
  consider animal as well as seasonal influenza
  virus infections in their differential diagnosis
  of patients who have febrile respiratory illness
  and who 1) live in San Diego and Imperial
  counties or 2) traveled to these counties or were
  in contact with ill persons from these counties
  in the 7 days preceding their illness onset, or
  3) had recent exposure to pigs.
• http//www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0421
  a1.htm

3
FLU

• True influenza
• influenza virus A or influenza virus B
• (or influenza virus C infections - much milder)
• Febrile respiratory disease with systemic
  symptoms caused by a variety of other organisms
  often inaccurately called flu

4
South Carolina 1996-1997 DHEC bulletin
malathia influenzae per le stelle
no virus
CULTURE RESULTS
influenza A
influenza B
SEASONAL INFLUENZA
http//www.state.sc.us/dhec/LAB/labbu017.htm
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THE IMPACT OF INFLUENZAPANDEMICS
Deaths
6
THE IMPACT OF INFLUENZA

• In the US, 1990-1999, on average
• 36,000 deaths per year
• 226,000 hospitalizations per year

http//www.cdc.gov/flu/professionals/acip/clinical
.htm
7
ORTHOMYXOVIRUSES

• pleomorphic
• influenza types A,B,C
• febrile, respiratory illness with systemic
  symptoms

http//www.uct.ac.za/depts/mmi/stannard/fluvirus.h
tml
8
ORTHOMYXOVIRUSES
type A, B, C NP, M1 protein sub-types HA or
NA protein
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TRANSMISSION

• AEROSOL
• 100,000 TO 1,000,000 VIRIONS PER DROPLET
• SURFACES
• - VIRUS CAN SURVIVE APPROX 2 TO 8 HRS
• 18-72 HR INCUBATION
• SHEDDING

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NORMAL TRACHEAL MUCOSA
3 DAYS POST-INFECTION
7 DAYS POST-INFECTION
Lycke and Norrby Textbook of Medical Virology
1983 Ramphal et al., INFECTION AND IMMUNITY 1979
25992-997 (mouse)
11

• DECREASED CLEARANCE
• RISK BACTERIAL INFECTION
• VIREMIA RARE

Lycke and Norrby Textbook of Medical Virology 1983
12
RECOVERY

• INTERFERON - SIDE EFFECTS INCLUDE
• FEVER, MYALGIA, FATIGUE, MALAISE
• CELL-MEDIATED IMMUNE RESPONSE
• TISSUE REPAIR
• CAN TAKE SOME TIME

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An immunological diversion

• INTERFERON

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INTERFERON
time course of virus production will vary from
virus to virus
15
INTERFERON
16
INTERFERON
17
INTERFERON
18
INTERFERON
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INTERFERON
THE VIRUSES ARE COMING!
PAUL REVERE http//www.mfa.org/collections/one_hou
r/6.htm
http//www.paulreverehouse.org/midnight.html
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TYPES OF INTERFERON

• TYPE I
• Interferon-alpha (leukocyte interferon, about 20
  related proteins)
• - leukocytes, etc
• Interferon-beta (fibroblast interferon)
• - fibroblasts, epithelial cells, etc
• TYPE II
• Interferon-gamma (immune interferon)
• - certain activated T-cells, NK cells

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INDUCTION OF INTERFERON

• interferon-alpha and interferon-beta
• induced by
• viral infection (especially RNA viruses)
• double stranded RNA
• certain bacterial components
• - strong anti-viral properties
• interferon-gamma
• - antigens, mitogenic stimulation of lymphocytes

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INTERFERON

• induces variety of proteins in target cells
• many consequences, not all fully understood

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INTERFERON-ALPHA AND INTERFERON-BETA
24
interferon-alpha, interferon-beta
interferon receptor
induction of 25oligo A synthase
induction of protein kinase R (PKR)
induction of ribonuclease L
25oligo A
activated ribonuclease L
activated protein kinase R
activated 25oligo A synthase
ATP
ATP
phosphorylated initiation factor (eIF-2)
25oligo A
mRNA degraded
inhibition of protein synthesis
25
interferon-alpha, interferon-beta
interferon receptor
induction of 25oligo A synthase
induction of protein kinase R (PKR)
induction of ribonuclease L
ds RNA
ds RNA
25oligo A
activated ribonuclease L
activated protein kinase R
activated 25oligo A synthase
ATP
ATP
phosphorylated initiation factor (eIF-2)
25oligo A
mRNA degraded
inhibition of protein synthesis
26
interferons

• only made when needed

27
OTHER EFFECTS OF INTERFERONS

• ALL TYPES
• INCREASE MHC I EXPRESSION
• CYTOTOXIC T-CELLS
• ACTIVATE NK CELLS
• CAN KILL VIRALLY INFECTED CELLS

28
OTHER EFFECTS OF INTERFERONS

• INTERFERON-GAMMA
• INCREASES MHC II EXPRESSION ON APC
• HELPER T-CELLS
• INCREASES ANTIVIRAL POTENTIAL OF MACROPHAGES
• INTRINSIC
• EXTRINSIC

29
THERAPEUTIC USES OF INTERFERONS

• ANTI-VIRAL
• e.g. interferon-alpha is currently approved for
  certain cases of acute and chronic HCV and
  chronic HBV
• MACROPHAGE ACTIVATION
• interferon-gamma has been tried for e.g.
  lepromatous leprosy, leishmaniasis, toxoplasmosis
• ANTI-TUMOR
• have been used in e.g. melanoma, Kaposis
  sarcoma, CML
• MULTIPLE SCLEROSIS
• interferon-beta

30
Viral response to host immune system

• Viruses may
• block interferon binding
• inhibit function of interferon-induced proteins
• interfere with MHC I or MHC II expression
• inhibit NK function
• block complement activation
• inhibit apoptosis
• etc!

31
SIDE EFFECTS OF INTERFERONS

• FEVER
• MALAISE
• FATIGUE
• MUSCLE PAINS

32
BACK TO INFLUENZA
33
SYMPTOMS

• FEVER
• HEADACHE
• MYALGIA
• COUGH
• RHINITIS
• OCULAR SYMPTOMS
• GI tract symptoms not typically seen
• but common with 2009 H1N1 influenza (swine flu)
• vomiting, diarrhea

34
INTERFERON
time course of virus production will vary from
virus to virus
35
PROTECTION AGAINST RE-INFECTION

• IgG and IgA
• IgG less efficient but lasts longer
• antibodies to both HA and NA important
• antibody to HA more important (can neutralize)

36
CLINICAL FINDINGS

• SEVERITY
• VERY YOUNG
• ELDERLY
• IMMUNO-COMPROMISED
• HEART OR LUNG DISEASE

37
PULMONARY COMPLICATIONS

• CROUP (YOUNG CHILDREN)
• PRIMARY INFLUENZA VIRUS PNEUMONIA
• SECONDARY BACTERIAL INFECTION
• Streptococcus pneumoniae
• Staphlyococcus aureus
• Hemophilus influenzae

38
NON-PULMONARY COMPLICATIONS

• myositis (rare, gt in children, gt with type B)
• cardiac complications
• encephalopathy
• 2002/2003 season studies of patients younger
  than 21 yrs in Michigan - 8 cases (2 deaths)
• liver and CNS
• Reyes syndrome
• peripheral nervous system
• Guillian-Barré syndrome

39
Reyes syndrome

• liver - fatty deposits
• brain - edema
• vomiting, lethargy, coma
• risk factors
• youth
• certain viral infections (influenza, chicken pox)
• aspirin

40
Guillian-Barré syndrome

• peripheral nervous system involved
• autoimmune
• 3000-6000 cases per year US
• most recover fully
• may follow infectious disease
• Campylobacter jejuni one of most common risk
  factors
• may be associated with some viral infections
• 1976/77 swine flu vaccine
• 35,000,000 doses
• 354 cases of GBS (approx 1-2 additional cases per
  100,000 vaccinated)
• 28 GBS-associated deaths
• recent infuenza vaccines much lower risk
• risk from vaccination much lower than risk from
  infection

41
MORTALITY
SEASONAL INFLUENZA

• MAJOR CAUSES OF INFLUENZA VIRUS- ASSOCIATED DEATH
• BACTERIAL PNEUMONIA
• CARDIAC FAILURE
• 90 OF DEATHS IN THOSE OVER 65 YEARS OF AGE

42
DIAGNOSIS

• ISOLATION
• NOSE, THROAT SWAB
• GROW IN TISSUE CULTURE OR EGGS
• SEROLOGY
• PCR
• RAPID TESTS
• provisional - clinical picture outbreak

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HA protein - attachment, fusion
membrane
inside of virion
antibody
44
NA protein - neuraminidase
membrane
inside of virion
antibody
45
ANTIGENIC DRIFT

• HA and NA accumulate mutations
• RNA virus
• immune response no longer protects fully
• sporadic outbreaks, limited epidemics

46
ANTIGENIC SHIFT

• new HA or NA proteins
• pre-existing antibodies do not protect
• may get pandemics

47
INFLUENZA A PANDEMICS
Ryan et al., in Sherris Medical Microbiology
2009 H1N1 A/California/07/2009 (H1N1)
48
where do new HA and NA come from?

• 16 types HA
• 9 types NA
• all circulate in birds
• pigs
• can be infected by avian and human influenza
  viruses

49
Where do new HA and NA come from?
50
(No Transcript)
51
Where do new HA and NA come from2009 PANDEMIC
H1N1?
52
Where do new HA and NA come from- can new
bird flu directly infect humans?
Current Bird flu H5N1? 1918 influenza
53
H5N1 in birds

• Avian H5N1 has spread to humans
• So far human cases in Asia and Africa
• 442 cases (12-1-03 through 09-24-09)
• 262 (59) fatal
• Have been a few instances where may have spread
  human-to-human
• So far no sustained spread in humans
• Surveillance continues

54
2009 NOVEL H1N1 PANDEMIC

• first novel H1N1 patient in the United States
  confirmed by laboratory testing at CDC on April
  15, 2009.
• Quickly determined that the virus was spreading
  from person-to-person.
• By June 3, 2009, all 50 states in the United
  States and the District of Columbia and Puerto
  Rico were reporting cases of novel H1N1
  infection.

http//www.cdc.gov/h1n1flu/update.htm
55
why do we not have influenza B pandemics?

• so far no shifts have been recorded
• no animal reservoir known

56
SURVEILLANCE
http//www.csiro.au/science/AIatAAHL.html
57
typed cases
influenza season
58
actual percentage of deaths
CDC http//www.cdc.gov/flu/weekly/
59
VACCINE

• BEST GUESS OF MAIN ANTIGENIC TYPES
• CURRENTLY SEASONAL VACCINE TRIVALENT
• type A - H1N1
• type A - H3N2
• type B
• each year choose which strain of each subtype is
  the best to use for optimal protection
• the 2009-2010 trivalent vaccine for seasonal
  influenza has
• A/Brisbane/59/2007 (H1N1)-like
• A/Brisbane/10/2007 (H3N2)-like
• B/Brisbane/60/2008

60
VACCINE

• inactivated (trivalent inactivated influenza
  vaccine, TIV)
• egg grown
• some formulations licensed for children
• reassortant, trivalent live vaccine (live
  attenuated vaccine, LAIV)
• egg grown
• for healthy non-pregnant persons (those not at
  risk for complications from influenza infection)
  ages 2-49 years
• (not approved for children under 5yrs with a
  history of recurrent wheezing)

61
usual timing 2009 rather different
CDC
62

• http//www.cdc.gov/flu/professionals/acip/flu_vax_
  adults0910.htmbox2

63

• http//www.cdc.gov/flu/professionals/acip/flu_vax_
  children0910.htmbox1

64
PREVENTION - DRUGS

• ZANAMIVIR (NA)
• types A and B
• OSELTAMIVIR (NA)
• types A and B
• RIMANTADINE (M2)
• type A only
• AMANTADINE (M2)
• type A only
• 2005 to present high levels of resistance of
  influenza A viruses to amantidine and
  rimantidine, so these drugs not recommended until
  resistance drops
• have been reports of some strains being
  oseltamivir resistant
• pandemic 2009 H1N1 is sensitive

surveillance and rapid diagnosis techniques
important in determining optimal drug treatment
65
TREATMENT - DRUGS

• ZANAMIVIR (NA)
• types A and B, needs to be given early
• OSELTAMIVIR (NA)
• types A and B, needs to be given early
• (some resistant strains but resistant strains
  currently still sensitive to zanamivir)
• RIMANTADINE (M2)
• type A only, needs to be given early
• currently resistance problems so not recommended
• AMANTADINE (M2)
• type A only, needs to be given early
• currently resistance problems so not recommended

66
NA protein - neuraminidase
.
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OTHER TREATMENT

• REST, LIQUIDS, ANTI-FEBRILE AGENTS (NO ASPIRIN
  FOR AGES 6MTHS-18YRS)
• BE AWARE OF COMPLICATIONS AND TREAT APPROPRIATELY

68
TYPE A yes yes yes shift,
drift yes (sensitive) sensitive (sensitive) 2
severity of illness animal reservoir human
pandemics human epidemics antigenic
changes segmented genome amantadine,
rimantidine zanamivir, oseltamivir surface
glycoproteins
TYPE B no no yes drift yes no
effect sensitive sensitive 2
TYPE C no no no (sporadic) drift yes no
effect (1)
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seasonal
pandemic

• Outbreaks follow predictable seasonal patterns
  occurs annually, usually in winter, in temperate
  climates
• Usually some immunity built up from previous
  exposure
• Healthy adults usually not at risk for serious
  complications the very young, the elderly and
  those with certain underlying health conditions
  at increased risk for serious complications
• Health systems can usually meet public and
  patient needs
• Vaccine developed based on known flu strains and
  available for annual flu season
• Adequate supplies of antivirals are usually
  available
• Average U.S. deaths approximately 36,000/yr
• Symptoms fever, cough, runny nose, muscle pain.
  Deaths often caused by complications, such as
  pneumonia.
• Generally causes modest impact on society (e.g.,
  some school closing, encouragement of people who
  are sick to stay home)
• Manageable impact on domestic and world economy

• Occurs rarely (a few times a century)
• No previous exposure little or no pre-existing
  immunity
• Healthy people may be at increased risk for
  serious complications
• Health systems may be overwhelmed
• Vaccine probably would not be available in the
  early stages of a pandemic
• Effective antivirals may be in limited supply
• Number of deaths could be quite high (e.g., U.S.
  1918 death toll approximately 675,000)
• Symptoms may be more severe and complications
  more frequent
• May cause major impact on society (e.g.
  widespread restrictions on travel, closings of
  schools and businesses, cancellation of large
  public gatherings)
• Potential for severe impact on domestic and world
  economy

www.pandemicflu.gov/season_or_pandemic.html
70

• Swine Influenza A (H1N1) Infection in Two
  Children --- Southern California, March--April
  2009
• On April 17, 2009, CDC determined that two cases
  of febrile respiratory illness occurring in
  children who resided in adjacent counties in
  southern California were caused by infection with
  a swine influenza A (H1N1) virus. The viruses
  from the two cases are closely related
  genetically, resistant to amantadine and
  rimantadine, and contain a unique combination of
  gene segments that previously has not been
  reported among swine or human influenza viruses
  in the United States or elsewhere. Neither child
  had contact with pigs the source of the
  infection is unknown. Investigations to identify
  the source of infection and to determine whether
  additional persons have been ill from infection
  with similar swine influenza viruses are ongoing.
  Although this is not a new subtype of influenza A
  in humans, concern exists that this new strain of
  swine influenza A (H1N1) is substantially
  different from human influenza A (H1N1) viruses,
  that a large proportion of the population might
  be susceptible to infection, and that the
  seasonal influenza vaccine H1N1 strain might not
  provide protection. The lack of known exposure to
  pigs in the two cases increases the possibility
  that human-to-human transmission of this new
  influenza virus has occurred. Clinicians should
  consider animal as well as seasonal influenza
  virus infections in their differential diagnosis
  of patients who have febrile respiratory illness
  and who 1) live in San Diego and Imperial
  counties or 2) traveled to these counties or were
  in contact with ill persons from these counties
  in the 7 days preceding their illness onset, or
  3) had recent exposure to pigs.
• http//www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0421
  a1.htm

71
the end...............
72
SEASONAL INFLUENZA
http//www.cdc.gov/flu/professionals/acip/clinical
.htmsigns
73

• Novel Influenza A Virus Jan 24th 2009 (week 3)
• One case of human infection with a novel
  influenza A virus was reported by the South
  Dakota Department of Health during week 3. The
  person was infected with a swine influenza A
  (H1N1) virus, and an investigation is currently
  underway to determine the source of illness.
  Although human infection with swine influenza is
  uncommon, sporadic cases have occurred in many
  years, usually among people in direct contact
  with ill pigs or who have been in places where
  pigs may have been present (e.g. agricultural
  fairs or farms). The sporadic cases of human
  infections with swine influenza viruses
  identified in recent years have not resulted in
  sustained human-to-human transmission or
  community outbreaks. Nonetheless, when cases are
  identified, CDC recommends thorough
  investigations to evaluate the extent of the
  outbreak and possible human to human
  transmission, as transmission patterns may change
  with changes in swine influenza viruses.
• (This was a regular swine flu virus, not the
  pandemic strain)

74
Public health response 2009

• April 15, 2009
• The first novel H1N1 patient in the US was
  confirmed by laboratory testing at CDC.
• April 17, 2009
• The second patient was confirmed.
• It was quickly determined that the virus was
  spreading from person-to-person.
• April 22, 2009
• CDC activated its Emergency Operations Center to
  better coordinate the public health response
• April 26, 2009
• The US Government declared a public health
  emergency and actively implemented the nations
  pandemic response plan

• http//www.cdc.gov/h1n1flu/background.htm

75
06-19-2009

• The first novel H1N1 patient in the United States
  was confirmed by laboratory testing at CDC on
  April 15, 2009. The second patient was confirmed
  on April 17, 2009. It was quickly determined that
  the virus was spreading from person-to-person. On
  April 22, CDC activated its Emergency Operations
  Center to better coordinate the public health
  response. On April 26, 2009, the United States
  Government declared a public health emergency and
  has been actively and aggressively implementing
  the nations pandemic response plan.
• Since the outbreak was first detected, an
  increasing number of U.S. states have reported
  cases of novel H1N1 influenza with associated
  hospitalizations and deaths. By June 3, 2009, all
  50 states in the United States and the District
  of Columbia and Puerto Rico were reporting cases
  of novel H1N1 infection.
• June 19th 2009. While nationwide U.S. influenza
  surveillance systems indicate that overall
  influenza activity is decreasing in the country
  at this time, novel H1N1 outbreaks are ongoing in
  parts of the U.S., in some cases with intense
  activity.CDC is continuing to watch the
  situation carefully, to support the public health
  response and to gather information about this
  virus and its characteristics. The Southern
  Hemisphere is just beginning its influenza season
  and the experience there may provide valuable
  clues about what may occur in the Northern
  Hemisphere this fall and winter.

http//www.cdc.gov/h1n1flu/update.htm
- downloaded 6/22/09
76
(No Transcript)
77
Influenza - USA
SEASONAL INFLUENZA

• Estimated rates of influenza-associated
  hospitalizations and deaths varied substantially
  by age group in studies conducted during
  different influenza epidemics.
• During 1990--1999, estimated average rates of
  influenza-associated pulmonary and circulatory
  deaths per 100,000 persons were
• 0.4--0.6 among persons aged 0--49 years
• 7.5 among persons aged 50--64 years
• 98.3 among persons aged 65 years and older.

http//www.cdc.gov/flu/professionals/acip/clinical
.htmsigns
78
Novel H1N1 U.S. Hospitalization Rate per 100,000
Population, By Age Group (07-31-09)
                                                  
                                                  
                                            
http//www.cdc.gov/h1n1flu/surveillanceqa.htm
79

• Danger signs in all patients
• Worldwide, the majority of patients infected with
  the pandemic virus continue to experience mild
  symptoms and recover fully within a week, even in
  the absence of any medical treatment.
• In addition to the enhanced risk documented in
  pregnant women, groups at increased risk of
  severe or fatal illness include people with
  underlying medical conditions, most notably
  chronic lung disease (including asthma),
  cardiovascular disease, diabetes, and
  immunosuppression. Some preliminary studies
  suggest that obesity, and especially extreme
  obesity, may be a risk factor for more severe
  disease.
• Within this largely reassuring picture, a small
  number of otherwise healthy people, usually under
  the age of 50 years, experience very rapid
  progression to severe and often fatal illness,
  characterized by severe pneumonia that destroys
  the lung tissue, and the failure of multiple
  organs. No factors that can predict this pattern
  of severe disease have yet been identified,
  though studies are under way.
• As progression can be very rapid, medical
  attention should be sought when any of the
  following danger signs appear in a person with
  confirmed or suspected H1N1 infection
• shortness of breath, either during physical
  activity or while resting
• difficulty in breathing
• turning blue
• bloody or colored sputum
• chest pain
• altered mental status
• high fever that persists beyond 3 days
• low blood pressure
• In children, danger signs include fast or
  difficult breathing, lack of alertness,
  difficulty in waking up, and little or no desire
  to play.

2009 PANDEMIC INFLUENZA

• http//www.who.int/csr/disease/swineflu/notes/h1n1
  _pregnancy_20090731/en/index.html , downloaded
  7-31-09

80
And every Ph.D. or pupilUtterly devoid of
scrupleMates me with complete abandon?Asks,
then, why my genes are randomCan I kiss and
never tellWhen genotyped upon a gel?Which, if
inspected with acuityWill document my
promiscuity?Must you write, in fat reportsHow
flagrantly I reassort?No boundaries have my
misbehavin'Horsey set or duck or avian?In other
moments less sublimeYou've put my perils before
swine!And yet in 1981Despite the work that has
been doneThe epidemics come and goAs regular as
winter snow.And people cough and people dieAnd
all of you still wonder why.I'm so perverse and
ever mutableAnd so eternally unscrutable.But
think about just what you'd doIf there were
reallyNo more flu!
A Rondelay (Without Cadenza) By The Virion Of
Influenza (by Edwin D. Kilbourne) Now you have
me?sucrose-banded,Enveloped and
negative-strandedSpiked and cleaved and slightly
dentedInto pieces eight, segmented?Without
mercy I've been strainedThrough filters?then
been bromelained, andTorn apart by each
detergentWith a haste unseemly, urgent?All my
helices displayedJust to show you how I'm
made.My polypeptides have been mappedMy
hemagglutinin unwrapped?All my sequences are
clear?All the way from Arg to Ser.With
techniques sharp and newly honedMy very genes
have now been cloned?Transplanted to an alien
hostWherein my evanescent ghostAs solitary as
an elfHas managed to express myself.And
scientists have labored nightsTo probe my
antigenic sitesSome fresh from school with new
diplomas(Aided by their hybridomas)Scramble up
trimeric slopesCounting all my epitopes
http//www.cdc.gov/eid/content/14/2/359.htm?s_cid
eid359_e