SlideShare a Scribd company logo

Orthomyxoviruses

orthomyxovirus

1 of 9
Download to read offline
Orthomyxoviruses
ORTHOMYXOVIRUSES
• Linear
• 8 segmented(7 in influenza C) RNA
• Negative sense, single stranded RNA
• Replication take place in cytoplasm
• Helical
• Enveloped
2
ORTHOMYXOVIRUSES
3
Group V: (-)sense RNA Viruses
Family
(Subfamily)
Genus Type Species Hosts
Orthomyxoviridae Influenza A virus Influenza A virus Vertebrates
Influenza B virus Influenza B virus Vertebrates
Influenza C virus Influenza C virus Vertebrates
Isavirus Infectious
salmon anemia
virus
Vertebrates
Thogotovirus Thogoto virus Vertebrates
4
Pathogenesis & Pathology
• Spreads from person to person by airborne droplets, or
contaminated hands and surfaces.
• Viral NA lowers the viscosity of the mucous film in the resp T,
exposing the cellular surface receptors and promoting the
spread of virus-containing fluid to lower resp T. Within short
time, many resp cells are infected and eventually killed.
• Interferon is effective against influenza virus and attributes to
host recovery.
• Influenza infections cause cellular destruction and
desquamation of superficial mucosa of the respiratory tract but
do not affect the basal layer of epithelium. Viral damage in the
epith lowers its resistance to secondary bacterial invaders esp
staphylococci, streptococci and Haemophilus influenzae.
5
Clinical findings
• Uncomplicated Influenza : Abrupt symptoms include
chills, headache, dry cough, muscular aches. These
may be induced by influenza A or B. In contrast,
influenza C causes a common cold illness, Coryza.
• Pneumonia : complications occur only in the elderly
and debilitated. Influenza infection enhances the
susceptibility of patients to bacterial superinfection,
due to loss of ciliary clearance, dysfunction of
phagocytic cells.
• Reye’s Syndrome : an acute encephalopathy of
children and adolescents (2-16yrs)
6
Prevention & Control by Vaccines
• A) Inactivated Viral Vaccines:
• Parenteral use;usually contain 1 or 2 type A and a type B
viruses, isolated from previous winter’s outbreaks.
• Strains are grown in embryonated eggs and the virus is
harvested from egg allantoic fluid.
• Vaccines are either whole virus (WV), subvirion (SV), or
surface Ag (SAg) preparations. WV=contains intact, inactivated
virus; SV=purified virus disrupted with detergents; SAg
contains purified HA and NA glycoproteins.
• Sometimes called “flu shot” or “flu jab”.
7
Prevention & Control by Vaccines
• B) Live Attenuated Influenza Vaccine
• Contains live but attenuated (weakened) vaccine. It is sprayed
into nostril.
• For both types of vaccines, it will take up to 2 weeks to
develop protection after vaccination.
• The synthetic drugs amantadine and rimantadine
hydrochloride effectively prevent infection and illness caused
by type A, but not by type B, viruses. The drugs interfere with
virus uncoating and transport by blocking the transmembrane
M2 ion channel (see fig of replication).
8
9

More Related Content

What's hot (20)

Orthomyxovirus
Orthomyxovirus Orthomyxovirus
Orthomyxovirus
 
Poxvirus
PoxvirusPoxvirus
Poxvirus
 
POXVIRUSES.ppt
POXVIRUSES.pptPOXVIRUSES.ppt
POXVIRUSES.ppt
 
Parvo virus
Parvo virusParvo virus
Parvo virus
 
Adenoviruses
AdenovirusesAdenoviruses
Adenoviruses
 
Picorna viruses
Picorna virusesPicorna viruses
Picorna viruses
 
Reoviridae
ReoviridaeReoviridae
Reoviridae
 
Poliovirus
PoliovirusPoliovirus
Poliovirus
 
Bacillus anthracis
Bacillus anthracisBacillus anthracis
Bacillus anthracis
 
paramyxovirus.ppt
paramyxovirus.pptparamyxovirus.ppt
paramyxovirus.ppt
 
Rickettsia
RickettsiaRickettsia
Rickettsia
 
Pox virus
Pox virusPox virus
Pox virus
 
General properties of viruses
General properties of virusesGeneral properties of viruses
General properties of viruses
 
25. rabies virus
25. rabies virus25. rabies virus
25. rabies virus
 
Haemophilus
HaemophilusHaemophilus
Haemophilus
 
Polio virus
Polio virusPolio virus
Polio virus
 
Poliovirus
PoliovirusPoliovirus
Poliovirus
 
Mycobacterium Tuberculosis
Mycobacterium TuberculosisMycobacterium Tuberculosis
Mycobacterium Tuberculosis
 
Bacillus
Bacillus Bacillus
Bacillus
 
Paramyxovirus
ParamyxovirusParamyxovirus
Paramyxovirus
 

Similar to Orthomyxoviruses

Orthomyxoviruses.ppt
Orthomyxoviruses.pptOrthomyxoviruses.ppt
Orthomyxoviruses.pptBVRamana9
 
Picornaviruses presentation Farhang Shapouran
Picornaviruses presentation  Farhang ShapouranPicornaviruses presentation  Farhang Shapouran
Picornaviruses presentation Farhang ShapouranFarhangShapouran
 
Adenovirus Microbiology
Adenovirus MicrobiologyAdenovirus Microbiology
Adenovirus Microbiologysantusan
 
Chickenpox: Pathophysiology
Chickenpox: PathophysiologyChickenpox: Pathophysiology
Chickenpox: PathophysiologyNimra Neyaz
 
Enteroviruses-1(0).pdf
Enteroviruses-1(0).pdfEnteroviruses-1(0).pdf
Enteroviruses-1(0).pdfMishiSoza
 
Othomyxo and paramyxoviruses
Othomyxo and paramyxovirusesOthomyxo and paramyxoviruses
Othomyxo and paramyxovirusesKaveh Haratian
 
Basic concept of virus for nursing and vaccine preventable viruses [Autosav...
Basic concept of virus for nursing and vaccine  preventable  viruses [Autosav...Basic concept of virus for nursing and vaccine  preventable  viruses [Autosav...
Basic concept of virus for nursing and vaccine preventable viruses [Autosav...OlisaEnebeli1
 
Orthomyxovirus, Influenza.pptx
Orthomyxovirus, Influenza.pptxOrthomyxovirus, Influenza.pptx
Orthomyxovirus, Influenza.pptxShishirer Vor
 
Myxoviruses (Inluenza, Mumps, Measles, Rubella)
Myxoviruses (Inluenza, Mumps, Measles, Rubella)Myxoviruses (Inluenza, Mumps, Measles, Rubella)
Myxoviruses (Inluenza, Mumps, Measles, Rubella)Alok Kumar
 
Structure of Animal Viruses
Structure of Animal Viruses  Structure of Animal Viruses
Structure of Animal Viruses Amani Riyadh
 

Similar to Orthomyxoviruses (20)

Orthomyxoviruses.ppt
Orthomyxoviruses.pptOrthomyxoviruses.ppt
Orthomyxoviruses.ppt
 
Picornaviruses presentation Farhang Shapouran
Picornaviruses presentation  Farhang ShapouranPicornaviruses presentation  Farhang Shapouran
Picornaviruses presentation Farhang Shapouran
 
Influenza
InfluenzaInfluenza
Influenza
 
Adenovirus Microbiology
Adenovirus MicrobiologyAdenovirus Microbiology
Adenovirus Microbiology
 
Chickenpox: Pathophysiology
Chickenpox: PathophysiologyChickenpox: Pathophysiology
Chickenpox: Pathophysiology
 
Lecture #2 (2).ppt
Lecture #2 (2).pptLecture #2 (2).ppt
Lecture #2 (2).ppt
 
Enteroviruses-1(0).pdf
Enteroviruses-1(0).pdfEnteroviruses-1(0).pdf
Enteroviruses-1(0).pdf
 
AIDS
AIDSAIDS
AIDS
 
Othomyxo and paramyxoviruses
Othomyxo and paramyxovirusesOthomyxo and paramyxoviruses
Othomyxo and paramyxoviruses
 
Basic concept of virus for nursing and vaccine preventable viruses [Autosav...
Basic concept of virus for nursing and vaccine  preventable  viruses [Autosav...Basic concept of virus for nursing and vaccine  preventable  viruses [Autosav...
Basic concept of virus for nursing and vaccine preventable viruses [Autosav...
 
orthomyxovirus slides
orthomyxovirus slidesorthomyxovirus slides
orthomyxovirus slides
 
Enteroviruses
EnterovirusesEnteroviruses
Enteroviruses
 
Orthomyxovirus, Influenza.pptx
Orthomyxovirus, Influenza.pptxOrthomyxovirus, Influenza.pptx
Orthomyxovirus, Influenza.pptx
 
Myxoviruses (Inluenza, Mumps, Measles, Rubella)
Myxoviruses (Inluenza, Mumps, Measles, Rubella)Myxoviruses (Inluenza, Mumps, Measles, Rubella)
Myxoviruses (Inluenza, Mumps, Measles, Rubella)
 
Structure of Animal Viruses
Structure of Animal Viruses  Structure of Animal Viruses
Structure of Animal Viruses
 
Picornavirus
PicornavirusPicornavirus
Picornavirus
 
Orthomyxoviruses...
Orthomyxoviruses...Orthomyxoviruses...
Orthomyxoviruses...
 
Influenza
Influenza Influenza
Influenza
 
Virus host infection-module 1.1
Virus host infection-module 1.1Virus host infection-module 1.1
Virus host infection-module 1.1
 
Viruses & antiviral agents
Viruses & antiviral agentsViruses & antiviral agents
Viruses & antiviral agents
 

More from Noman-Hafeez khosa

Lentiviruses as a gene transferring agent
Lentiviruses as a gene transferring agentLentiviruses as a gene transferring agent
Lentiviruses as a gene transferring agentNoman-Hafeez khosa
 
Large scale microbial fermentation and its problem numair ahmad
Large scale microbial  fermentation and its problem numair ahmadLarge scale microbial  fermentation and its problem numair ahmad
Large scale microbial fermentation and its problem numair ahmadNoman-Hafeez khosa
 
Tissue culture and virology (cpe, plaque assay)
Tissue culture and virology (cpe, plaque assay)Tissue culture and virology (cpe, plaque assay)
Tissue culture and virology (cpe, plaque assay)Noman-Hafeez khosa
 
Properties of microorganism useful in bio industry-shahrain
Properties of microorganism useful in bio industry-shahrainProperties of microorganism useful in bio industry-shahrain
Properties of microorganism useful in bio industry-shahrainNoman-Hafeez khosa
 
Production of recombinent proteins, faisal munir
Production of recombinent proteins, faisal munirProduction of recombinent proteins, faisal munir
Production of recombinent proteins, faisal munirNoman-Hafeez khosa
 
Preparation of plasmid dna by M.Waqas & Noman Hafeez Khosa
Preparation of plasmid dna by M.Waqas & Noman Hafeez KhosaPreparation of plasmid dna by M.Waqas & Noman Hafeez Khosa
Preparation of plasmid dna by M.Waqas & Noman Hafeez KhosaNoman-Hafeez khosa
 
Uncouplers of oxidative phosphorylation
Uncouplers of oxidative phosphorylationUncouplers of oxidative phosphorylation
Uncouplers of oxidative phosphorylationNoman-Hafeez khosa
 

More from Noman-Hafeez khosa (20)

Lentiviruses as a gene transferring agent
Lentiviruses as a gene transferring agentLentiviruses as a gene transferring agent
Lentiviruses as a gene transferring agent
 
Large scale microbial fermentation and its problem numair ahmad
Large scale microbial  fermentation and its problem numair ahmadLarge scale microbial  fermentation and its problem numair ahmad
Large scale microbial fermentation and its problem numair ahmad
 
Tissue culture and virology (cpe, plaque assay)
Tissue culture and virology (cpe, plaque assay)Tissue culture and virology (cpe, plaque assay)
Tissue culture and virology (cpe, plaque assay)
 
Vaccine production somia
Vaccine production somiaVaccine production somia
Vaccine production somia
 
Properties of microorganism useful in bio industry-shahrain
Properties of microorganism useful in bio industry-shahrainProperties of microorganism useful in bio industry-shahrain
Properties of microorganism useful in bio industry-shahrain
 
Production of recombinent proteins, faisal munir
Production of recombinent proteins, faisal munirProduction of recombinent proteins, faisal munir
Production of recombinent proteins, faisal munir
 
Preparation of plasmid dna by M.Waqas & Noman Hafeez Khosa
Preparation of plasmid dna by M.Waqas & Noman Hafeez KhosaPreparation of plasmid dna by M.Waqas & Noman Hafeez Khosa
Preparation of plasmid dna by M.Waqas & Noman Hafeez Khosa
 
Marek's disease in poultry
Marek's disease in poultryMarek's disease in poultry
Marek's disease in poultry
 
Gel electrophoresis 08
Gel electrophoresis 08Gel electrophoresis 08
Gel electrophoresis 08
 
Triple sugar iron_agar
Triple sugar iron_agarTriple sugar iron_agar
Triple sugar iron_agar
 
13 digestion
13 digestion13 digestion
13 digestion
 
Cardiovascular system
Cardiovascular systemCardiovascular system
Cardiovascular system
 
Hyperplasia
HyperplasiaHyperplasia
Hyperplasia
 
Tissue repair
Tissue repairTissue repair
Tissue repair
 
Respiratory system
Respiratory systemRespiratory system
Respiratory system
 
Pcr & types
Pcr & typesPcr & types
Pcr & types
 
Bioreactors
BioreactorsBioreactors
Bioreactors
 
Uncouplers of oxidative phosphorylation
Uncouplers of oxidative phosphorylationUncouplers of oxidative phosphorylation
Uncouplers of oxidative phosphorylation
 
Antibiotics 1
Antibiotics 1Antibiotics 1
Antibiotics 1
 
corona virus
corona viruscorona virus
corona virus
 

Recently uploaded

Anatomy-Reproductive-System for grade 10
Anatomy-Reproductive-System for grade 10Anatomy-Reproductive-System for grade 10
Anatomy-Reproductive-System for grade 10rolanaribato30
 
Open Access Publishing in Astrophysics and the Open Journal of Astrophysics
Open Access Publishing in Astrophysics and the Open Journal of AstrophysicsOpen Access Publishing in Astrophysics and the Open Journal of Astrophysics
Open Access Publishing in Astrophysics and the Open Journal of AstrophysicsPeter Coles
 
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...dkNET
 
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptx
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptxCHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptx
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptxASWIN ANANDH
 
Lecture 9 .Parasympathetic agents.b pharmacy second year
Lecture 9 .Parasympathetic agents.b pharmacy second yearLecture 9 .Parasympathetic agents.b pharmacy second year
Lecture 9 .Parasympathetic agents.b pharmacy second yearmanjusha kareppa
 
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdf
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdfUKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdf
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdfThane Heins
 
Microbial Fermentation(Strain Improvement)
Microbial  Fermentation(Strain Improvement)Microbial  Fermentation(Strain Improvement)
Microbial Fermentation(Strain Improvement)Rachana Choudhary
 
Introduction to Chromatography (Column chromatography)
Introduction to Chromatography (Column chromatography)Introduction to Chromatography (Column chromatography)
Introduction to Chromatography (Column chromatography)Ahmed Metwaly
 
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...Uzay Emir
 
Presentacion Mariana Arango- biología molecular
Presentacion Mariana Arango- biología molecularPresentacion Mariana Arango- biología molecular
Presentacion Mariana Arango- biología molecularmarianaarangop
 
Presentation for first doctoral seminar on Advances in poultry nutrition.pptx
Presentation for first doctoral seminar on Advances in poultry nutrition.pptxPresentation for first doctoral seminar on Advances in poultry nutrition.pptx
Presentation for first doctoral seminar on Advances in poultry nutrition.pptxPallaviMali14
 
American Eclipse A Nation’s Epic Race to Catch the_240225_095603
American Eclipse A Nation’s Epic Race to Catch the_240225_095603American Eclipse A Nation’s Epic Race to Catch the_240225_095603
American Eclipse A Nation’s Epic Race to Catch the_240225_095603SOCIEDAD JULIO GARAVITO
 
Interpretation, measurement and mixed methods
Interpretation, measurement and mixed methodsInterpretation, measurement and mixed methods
Interpretation, measurement and mixed methodsTuukka Ylä-Anttila
 
Seminario biología molecular Lina Charris
Seminario biología molecular Lina CharrisSeminario biología molecular Lina Charris
Seminario biología molecular Lina CharrisLinaMarcelaCharrisRa
 
commercial production of cellulase enzyme and its uses
commercial production of cellulase enzyme and its usescommercial production of cellulase enzyme and its uses
commercial production of cellulase enzyme and its usesSilpa Selvaraj
 
A tale of two Lucys - Delft lecture - March 4, 2024
A tale of two Lucys - Delft lecture - March 4, 2024A tale of two Lucys - Delft lecture - March 4, 2024
A tale of two Lucys - Delft lecture - March 4, 2024Richard Gill
 
the menstrual cycle in female reproductive system
the menstrual cycle in female reproductive systemthe menstrual cycle in female reproductive system
the menstrual cycle in female reproductive systemGilmeTripole1
 
PSILOTUM : structure, morphology, anatomy, reproduction , life cycle etc.
PSILOTUM : structure, morphology, anatomy,  reproduction , life cycle etc.PSILOTUM : structure, morphology, anatomy,  reproduction , life cycle etc.
PSILOTUM : structure, morphology, anatomy, reproduction , life cycle etc.Silpa Selvaraj
 
Differences between syrups and elixirs .pptx
Differences between  syrups and elixirs .pptxDifferences between  syrups and elixirs .pptx
Differences between syrups and elixirs .pptxushakiranmai4
 

Recently uploaded (20)

Anatomy-Reproductive-System for grade 10
Anatomy-Reproductive-System for grade 10Anatomy-Reproductive-System for grade 10
Anatomy-Reproductive-System for grade 10
 
Open Access Publishing in Astrophysics and the Open Journal of Astrophysics
Open Access Publishing in Astrophysics and the Open Journal of AstrophysicsOpen Access Publishing in Astrophysics and the Open Journal of Astrophysics
Open Access Publishing in Astrophysics and the Open Journal of Astrophysics
 
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...
dkNET Webinar: The Collaborative Microbial Metabolite Center – Democratizing ...
 
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptx
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptxCHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptx
CHEMICAL TESTS FOR GLYCOSIDES AND ALKALOIDS.pptx
 
Lecture 9 .Parasympathetic agents.b pharmacy second year
Lecture 9 .Parasympathetic agents.b pharmacy second yearLecture 9 .Parasympathetic agents.b pharmacy second year
Lecture 9 .Parasympathetic agents.b pharmacy second year
 
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdf
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdfUKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdf
UKRAINIAN Kyiv Institute of Thermophysics Memorandum_English.pdf
 
Microbial Fermentation(Strain Improvement)
Microbial  Fermentation(Strain Improvement)Microbial  Fermentation(Strain Improvement)
Microbial Fermentation(Strain Improvement)
 
Introduction to Chromatography (Column chromatography)
Introduction to Chromatography (Column chromatography)Introduction to Chromatography (Column chromatography)
Introduction to Chromatography (Column chromatography)
 
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...
Lung imaging Using 3D Dual-Echo FID Ultra-short Echo Time MRI with novel Rose...
 
Presentacion Mariana Arango- biología molecular
Presentacion Mariana Arango- biología molecularPresentacion Mariana Arango- biología molecular
Presentacion Mariana Arango- biología molecular
 
Presentation for first doctoral seminar on Advances in poultry nutrition.pptx
Presentation for first doctoral seminar on Advances in poultry nutrition.pptxPresentation for first doctoral seminar on Advances in poultry nutrition.pptx
Presentation for first doctoral seminar on Advances in poultry nutrition.pptx
 
American Eclipse A Nation’s Epic Race to Catch the_240225_095603
American Eclipse A Nation’s Epic Race to Catch the_240225_095603American Eclipse A Nation’s Epic Race to Catch the_240225_095603
American Eclipse A Nation’s Epic Race to Catch the_240225_095603
 
Interpretation, measurement and mixed methods
Interpretation, measurement and mixed methodsInterpretation, measurement and mixed methods
Interpretation, measurement and mixed methods
 
Seminario biología molecular Lina Charris
Seminario biología molecular Lina CharrisSeminario biología molecular Lina Charris
Seminario biología molecular Lina Charris
 
commercial production of cellulase enzyme and its uses
commercial production of cellulase enzyme and its usescommercial production of cellulase enzyme and its uses
commercial production of cellulase enzyme and its uses
 
A tale of two Lucys - Delft lecture - March 4, 2024
A tale of two Lucys - Delft lecture - March 4, 2024A tale of two Lucys - Delft lecture - March 4, 2024
A tale of two Lucys - Delft lecture - March 4, 2024
 
the menstrual cycle in female reproductive system
the menstrual cycle in female reproductive systemthe menstrual cycle in female reproductive system
the menstrual cycle in female reproductive system
 
REGULATION OF METABOLISM IN PLANTS AND THE DIFFERENT MECHANISMS
REGULATION OF METABOLISM IN PLANTS  AND THE DIFFERENT MECHANISMSREGULATION OF METABOLISM IN PLANTS  AND THE DIFFERENT MECHANISMS
REGULATION OF METABOLISM IN PLANTS AND THE DIFFERENT MECHANISMS
 
PSILOTUM : structure, morphology, anatomy, reproduction , life cycle etc.
PSILOTUM : structure, morphology, anatomy,  reproduction , life cycle etc.PSILOTUM : structure, morphology, anatomy,  reproduction , life cycle etc.
PSILOTUM : structure, morphology, anatomy, reproduction , life cycle etc.
 
Differences between syrups and elixirs .pptx
Differences between  syrups and elixirs .pptxDifferences between  syrups and elixirs .pptx
Differences between syrups and elixirs .pptx
 

Orthomyxoviruses

  • 2. ORTHOMYXOVIRUSES • Linear • 8 segmented(7 in influenza C) RNA • Negative sense, single stranded RNA • Replication take place in cytoplasm • Helical • Enveloped 2
  • 4. Group V: (-)sense RNA Viruses Family (Subfamily) Genus Type Species Hosts Orthomyxoviridae Influenza A virus Influenza A virus Vertebrates Influenza B virus Influenza B virus Vertebrates Influenza C virus Influenza C virus Vertebrates Isavirus Infectious salmon anemia virus Vertebrates Thogotovirus Thogoto virus Vertebrates 4
  • 5. Pathogenesis & Pathology • Spreads from person to person by airborne droplets, or contaminated hands and surfaces. • Viral NA lowers the viscosity of the mucous film in the resp T, exposing the cellular surface receptors and promoting the spread of virus-containing fluid to lower resp T. Within short time, many resp cells are infected and eventually killed. • Interferon is effective against influenza virus and attributes to host recovery. • Influenza infections cause cellular destruction and desquamation of superficial mucosa of the respiratory tract but do not affect the basal layer of epithelium. Viral damage in the epith lowers its resistance to secondary bacterial invaders esp staphylococci, streptococci and Haemophilus influenzae. 5
  • 6. Clinical findings • Uncomplicated Influenza : Abrupt symptoms include chills, headache, dry cough, muscular aches. These may be induced by influenza A or B. In contrast, influenza C causes a common cold illness, Coryza. • Pneumonia : complications occur only in the elderly and debilitated. Influenza infection enhances the susceptibility of patients to bacterial superinfection, due to loss of ciliary clearance, dysfunction of phagocytic cells. • Reye’s Syndrome : an acute encephalopathy of children and adolescents (2-16yrs) 6
  • 7. Prevention & Control by Vaccines • A) Inactivated Viral Vaccines: • Parenteral use;usually contain 1 or 2 type A and a type B viruses, isolated from previous winter’s outbreaks. • Strains are grown in embryonated eggs and the virus is harvested from egg allantoic fluid. • Vaccines are either whole virus (WV), subvirion (SV), or surface Ag (SAg) preparations. WV=contains intact, inactivated virus; SV=purified virus disrupted with detergents; SAg contains purified HA and NA glycoproteins. • Sometimes called “flu shot” or “flu jab”. 7
  • 8. Prevention & Control by Vaccines • B) Live Attenuated Influenza Vaccine • Contains live but attenuated (weakened) vaccine. It is sprayed into nostril. • For both types of vaccines, it will take up to 2 weeks to develop protection after vaccination. • The synthetic drugs amantadine and rimantadine hydrochloride effectively prevent infection and illness caused by type A, but not by type B, viruses. The drugs interfere with virus uncoating and transport by blocking the transmembrane M2 ion channel (see fig of replication). 8
  • 9. 9