influenza (the flu) influenza (the flu) presented by: poormontaseri z, dm infectious diseases and...
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InfluenzaInfluenza (The flu) (The flu)
Presented by:
PoorMontaseri Z, DMInfectious Diseases and Tropical Medicine
Fasa University of Medical Science
In temperate climates, seasonal epidemics occur mainly during winter
In tropical regions, may occur throughout
the year, causing outbreaks more irregularly.
Influenza, commonly known as “the flu”, is a highly contagious infection of the airways caused by influenza viruses.
در پاندمي هاي ( و Asian flu ) 1957سالهاي
1968( Hong kong flu نيز به )نفر ميليون 2ترتيب حدود
نفر در 700/000و حدود سطح جهان کشته شده اند
The first cases of human infection with novel H1N1 influenza virus were detected in April 2009 in San Diego and Imperial County, California and in Guadalupe County, Texas.
The virus has spread rapidly.
Distribution of pandemic Distribution of pandemic H1N1H1N1
Distribution of Influenza in Iran
Iran reported an increase in influenza detections from previous weeks.
Influenza A(H1N1) viruses were predominant with some A(H3N2) and B detections reported.
RNA viruses/ Subfamily: Orthomyxoviridae. enveloped viruses that may exist in spherical or
filamentous forms of 80 to 120 nm
The Influenza VirusThe Influenza Virus
Antigenic drift?◦Minor change
Antigenic shift?◦Major change
Point Mutation of Hemagglutinin and Neuraminidase gene
Antigenic Drift
Antigenic Shift
Human H2N2
Avian H3N8
Genetic ReassortmentAntigenic Shift
Human H3N2
Generation of new Human Virus (H3N2)Possessing Hemagglutinin from Avian Virus (H3N8)
Survival of Influenza viruses in Survival of Influenza viruses in EnviromentEnviroment
Plastic and steels stuffs: more than 24 h
Cloths and papers: 8-12 h
Viable on hands: <5 minutes only at high viral titers
In virus classification influenza viruses are :
A Three known A subtypes of influenza viruses
currently circulating among humans (H1N1, H1N2, and H3N2).
B C
Bridges et al. 2008.
TypeHostClinical Importance
Pattern of Occurrence
SubtypesEpidemiology
A)seasonal, Avian, Swine(
Humans,birds, horses, other mammals
Moderate to severedisease
Sporadic,epidemics,pandemics
YesH1-H16
N1-N9
Antigenic shift /drift
B )seasonal(
Humans
Moderate to severe disease
Sporadic,epidemics
NoAntigenic drift
CHumansand swine
Milddisease
Sporadic, localized outbreaks
NoAntigenic drift
Avian InfluenzaAvian InfluenzaAvian influenza is an infectious disease of birds
caused by type A strains of the influenza virus.
Avian influenza transmitted by birds usually through
feces or saliva.
H5N1; the strain of avian flu, ◦ Most cases of avian influenza infection in humans
have resulted from contact with infected poultry
◦ The spread of avian influenza viruses from one ill person to another person has been reported very rarely
Swine Flu Swine Flu Swine influenza (swine flu) is a respiratory disease of
pigs caused by type A influenza virus.
The main swine influenza viruses circulating in U.S. pigs in recent years are: H1N1 influenza virus, H3N2 virus, H1N2 virus.
Disease was more severe among people younger than 65 years of age than in non-pandemic influenza seasons.
With significantly higher pediatric mortality, and higher rates of hospitalizations in children and young adults.
H1N1/H5N1H1N1/H5N1
high morbidity but low
mortality rates (1%-4%).
The estimated incubation period is unknown and could range from 1-7 days, and more likely 1-4 days.
Transmission Transmission and Evolutionand Evolution
Influenza virus is transmitted easily from person to person when speaking, by sneezing or coughing and can be confused with other severe Influenza illnesses caused by different viruses.
Adults may be contagious from one day prior to the commencement of symptoms to up to 7 days after becoming sick.
Children may be contagious for a period of up to 14 days after the appearance of symptoms.
Immuno-suppressed more than others.
Relationship between Relationship between mortality and involvement mortality and involvement ageage
Attack rates are generally highest in the young, (children aged 5--14 years)
whereas mortality is generally highest among older adults
SymptomsFluCold
FeverUsually 80%Rare
AchesSevere aches and painsOccasion slight body aches
ChillsFairly common (60%)Uncommon
TirednessModerate to severeMild
Sudden symptoms
Sudden often within 3-6h(chills /aches)
Not sudden develop over a few days
CoughNon-productive, dry cough (80%)
Hacking, productive cough
SneezingNot commonly present Commonly present
Stuffy noseNot commonly presentCommon but resolves within 1 week
Sore throatCan be presentCommon due to inflammation
Chest discomfort Severe, felt along front of body, neck to abdomen
Mild to moderate
HeadacheVery common (80%)Fairy uncommon
ComplicationPneumonia, can be life threatening
Sinus /ear infection
Complications of InfluenzaComplications of Influenza Pulmonary Complications
◦ primary influenza viral pneumonia and secondary bacterial infection (Streptococcus pneumoniae and Staphylococcus aureus)
Other Pulmonary Complications◦ Bronchiolitis◦ Croup◦ Acute exacerbation of chronic bronchitis◦ Exacerbations of asthma and worsening
pulmonary function in children with cystic fibrosis
Nonpulmonary Complications◦ Myositis
◦ Cardiac Complications )myocarditis and pericarditis , myocardial infarction)
◦ Toxic Shock Syndrome
◦ Central Nervous Complications (Guillain-Barré syndrome, Reye Syndrome)
DiagnosisDiagnosis
Clinical DiagnosisRapid Influenza Diagnostic TestsMolecular Diagnostic Tests (nucleic
acid hybridization and PCR)
Serology (complement fixation and hemagglutination inhibition)
Virus Isolation
InfluenzaInfluenza
Type A Influenza Can not be EradicatedType A Influenza Can not be Eradicated
Continous emergence of new virus variant
Prevention:Prevention:
1.Primary2.Secondary
Prevention in the HealthPrevention in the HealthCare SettingCare Setting
Patients with seasonal influenza can generally be managed under droplet precautions, except when undergoing aerosol-generating procedures, such as bronchoscopy, sputum induction, elective intubation and extubation, and autopsies, during which management requires airborne precautions.
Primary preventionPrimary prevention
VaccinationVaccination
www.fightflu.com
Vaccination/ Common side effects include:Vaccination/ Common side effects include:
Local reactions at the injection site (soreness, swelling, redness).
Possibly some systemic reactions (fever, headache, muscle or joint aches). these symptoms are mild, self-limited and last 1-2 days.
Guillian-Barre syndrome (1/1000000)
Secondary preventionSecondary prevention
Watch for emergency warningsignsMost people should be able to recover at home, but watch for emergency warning signs that mean you should seek immediate medical care.
In adults:Difficulty breathing or shortness of breathPain or pressure in the chest or abdomenSudden dizzinessConfusionSevere or persistent vomitingFlu-like symptoms improve but then return with fever and worse cough
Emergency warning signs inchildrenIf a child gets sick and experiences any of these warning
signs, seek emergency medical care.
In children:Fast breathing or trouble breathingBluish or gray skin colorNot drinking enough fluidsSevere or persistent vomitingNot waking up or not interactingIrritable, the child does not want to be heldFlu-like symptoms improve but then return with fever and worse
Secondary preventionSecondary prevention
Thanks for
your attention