(1) Orthomyxoviridae Flashcards
what is the common MOT for the family of orthomyxo, paramyxo, and rubella virus?
inhalation of contaminated respiratory droplets, large aerosol droplets
orthomyxo, paramyxo, and rubella virus shows clinical manifesttion when it infects the?
Upper respiratory tract infection
sometimes lower, or viremia (disseminated clinical picture)
major determinant of morbidity and mortality caused by respiratory disease and outbreak of the infection
Orthomyxoviridae (Influenza Virus)
common na sakit ang influenza (flu season)
what is the unique characteristic of Orthomyxoviridae?
Genetic reassrotment
why reoccurence of flu is possible for orthomyxoviridae?
Genetic reassortment (it creates new strain of virus every time)
mas malala pag flu season!
characteristic of Orthomyxoviridae
- Spherical in shape (100-120nm in diameter)
- Single stranded, Negative-sense RNA
- Enveloped
- Segmented
- Helical
- Replication: Cytoplasm
Orthomyxoviridae
Cell is coinfected by a 2 difference viruses of given type and forming a new strain
Genetic Reassortment
Orthomyxoviridae
Transmission
Direct contact or respiratory droplets
Orthomyxoviridae
Disease
influenza
Orthomyxoviridae
how many immunologic types are there in influenza
4
Influenza immunologic types
enumerate the 4 types
Influeza A, B, C, and D
Influenza immunologic types
most and best characterized
all of the characteristics studied are from this type
Influenza A
Influenza immunologic types
Only known to cause flu pandemic
Influenza A
Influenza immunologic types
Most stable; antigenically stable
Influenza C
Influenza immunologic types
Not associated with human infection
Influenza C and D
Influenza immunologic types
also antigenically stable
Not associated with human infection
Influenza D
or C (but C is MOST stable)
enumerate the important structure of unit of virus
- Nuceleoprotein (NP)
- vRNPs
- RNA Polymerase (PB1, PB2, PA)
- Matrix Protein (M1 and M2)
- Hemeagglutinin (HA)
- Neuraminidase (NA)
Structure of virus
associates with the viral RNA to form the ribonucleon protein (vRNPs)
Nuceleoprotein (NP)
Structure of virus
what is used to classify the influenza viruses
NP and M1
no cross reactivity with other structural protein
Structure of virus
forms the viral nucelocapsid
vRNPs (viral ribonucleoprotein complexes)
Structure of virus
Small protein (small sabi ni maam)
Responsible for transcription and replication of virus
RNA Polymerase (PB1, PB2, PA)
Structure of virus
Make the inner lining of the envelope
Matrix Protein 1
Structure of virus
Promote the assembly of the virion
Matrix Protein 1
Structure of virus
Responsible for the uncoating of the virion
Matrix Protein 2
Structure of virus
Channel for allowing the movement of the hydrogen so that the virion will escape the core
Its like a transmembrane na lodge
Matrix Protein 2
Structure of virus
what are the surface protein
Hemeagglutinin (HA) and Neruaminidase (NA)
Structure of virus
This 2 will determine the antigenic variation of the influenza virus and host immunity
Surface Protein: Hemeagglutinin (HA) and Neruaminidase (NA)
Structure of virus
Virus encoated glycoproteins
Exposed on the surface
Surface Protein: Hemeagglutinin (HA) and Neruaminidase (NA)
Structure of virus
Target of the antibody
Surface Protein: Hemeagglutinin (HA) and Neruaminidase (NA)
Structure of virus
capable of agglutinating the red blood cell
Hemeagglutinin (HA)
Structure of virus
surface protein that is more reactive with antibody
Hemeagglutinin (HA)
Structure of virus: surface protein
primarily responsible for the continual evolution of new strains
Hemeagglutinin (HA)
Structure of virus
Major antigen against Ab
Hemeagglutinin (HA)
Structure of virus
cleaved to HA1 and HA2 (to be infectious, if not cleaved not infections)
Hemeagglutinin (HA)
cleaved by proteases in the respiratory epithelium
Structure of virus
Responsible for binding with epithelial cells (as long as may sialic acid) – to infiltrate the human
Hemeagglutinin (HA)
Structure of virus
Sialidase enzyme – to break the bond between HA and sialic acid
will infect another cell once detached
Neruaminidase (NA)
Structure of virus
Facilitates the release of virus from infected cell surfaces (de-attaching or release of virus)
Neruaminidase (NA)
Structure of virus
Promotes viral spread
Neruaminidase (NA)
Structure of virus
main difference of Hemeagglutinin (HA) and Neruaminidase (NA)
HA - Attachment of antigen
NA - dettachment, for release of virus
if u see this card
kindly study the strains for influenza A and B ty babe
Identify the subtypes → clades → sub-clades
influenza A (first sub type)
A (H1N1) → 6B.1 → 6B.1A
Identify the subtypes → clades → sub-clades
influenza A (2nd sub type)
A (H3N2) → 3C.2a, 3C.3a → 3C.2a1; 3C.2a2; 3C.2a3; 3c.2a4
Identify the Lineages → clades → sub-clades
influenza B (victoria)
B(victoria) → V1A → V1A.1; V1A.2; V1A.3
Identify the Lineages → clades → sub-clades
influenza B (yamagata)
B (yamagata) → Y1, Y2, Y3 → None
Nomenclature of virus
- Virus type
- Place of virus (isolated)
- Strain number
- Year isolated
- Virus subtype
Ability to produce new strain, that is why we have occurrence flu virus
Characteristics of the virus
Antigenic Variation
Antigenic Variation
2 variables Responsible for the persistence of influenza virus
Antigenic Drift and Shift
Antigenic Variation - Drift or Shift
→ Minor antigenic changes
Antigenic Drift
Antigenic Variation - Drift or Shift
→ Occurs every year
Antigenic Drift
Antigenic Variation - Drift or Shift
→ Major antigenic changes
Antigenic Shift
Antigenic Variation - Drift or Shift
→ Risk of pandemic
Antigenic Shift
pandemic can be only occur in influenza A
Antigenic Variation - Drift or Shift
Vaccines must be given anually
Antigenic Drift
Antigenic Variation - Drift or Shift
→ RNA replication errors of virus or point mutation in the gene
Antigenic Drift
Antigenic Variation - Drift or Shift
→ (+) appearance of new subtypes
Antigenic Shift
Antigenic Variation - Drift or Shift
→ Only in Influenza A
Antigenic Shift
what are the 2 mechanism for antigenic shift
Genetic reassortment and Adaptive mutation
Antigenic Shift - Mechanism
single cell is infected with 2 virus of the same class and will form a new strain
Genetic reassortment
Antigenic Shift - Mechanism
wherein the virus slowly adjust and becomes transmissible to mammals (human)
Adaptive mutation
Major shift that occurred in the 20th century
- H1N1 or the spanish flu (1919-1918)
- H2N2 or asian flu (1957 - 1958)
- H3N2 or Hongkong flu (1968)
- H1N1 pdm or swine flu (2009)
Influenza A - TOF
All age groups can be affected but immunocompromised are at greater risk of severe disease
True
Influenza A
high risk acquiring influenza virus infection due to increased exposure to the patients and risk further spread particularly to vulnerable Individuals.
Health care workers
Influenza A
In temperate climates, seasonal epidemics occur mainly during
winter
Influenza A
while In tropical regions, Influenza may occur
throughout the year
Influenza A TOF
In tropical regions, Influenza may occur throughout the year –causing outbreaks more regular
False (irregular me na me)
Treatment for influenza A
Neuraminidase inhibitors: oseltamivir and zanamivir
Given once signs and symptoms initially present
treatment for influenza A should be given during?
onset or after 48 hours of the sign and symptoms
Laboratory Diagnosis
Specimen
asopharyngeal swabs, (nasal) washes aspirates
Laboratory Diagnosis
Orthomyxoviridae
recommended specimen
Flocked swabs - Higher yield for epithelial cell
what are the 3 procedures that can be done for laboratory diagnosis of orthomyxoviridae
- RT-PCR
- Culture
- Serological
check trans for definition
Prevention
who recommends the annual vaccination ?
WHO
tongue twsit ,who? edi WHO 🌽y
Prevention
WHO recommends annual vaccination for?
- Pregnant women
- Children
- Elderly individuals
- individuals with chronic medical conditions
- Health-care workers
Vaccination of influenza in the Philippines have a new delivery of the vaccine, ideally the flu vaccine should be done within
April or May
Viral Replication
enumerate the steps
- Bindinf to the target cell
- Taken inside the cell
- Hydrogen Ions will enter the endosomes of the virion
- Relase of the content into the cytoplasm
- Protein synthesis
- Replication
- Assembly
- Budding
- Release
Binding to the target cell
(1) This will bind to the sialic acid in the respiratory epithelial cell
Hemagglutinin
Viral replication
(2) Taken inside the cell, what method is used
clathrin mediated endocytosis
Viral replication
(3) This will then will enter the endosomes of the virion
Hydrogen Ions
Viral replication
what facilitate the endosome fusion
Hydrogen Ions
Viral Replcation
mediates the entrance of hydrogen ions
M2 or matrix protein 2
Viral Replcation
(4) Relase of the content into the
cytoplasm
Viral replication
unable to produce protein on its own
ssRNA, negative sense
Viral replication
They have their own RNA polymerase
ssRNA, negative sense
Viral replication
For it to be release fully, what is needed?
sialidase or neuramadase
breakdown of sialic acid
Viral replication
reakdown of sialic acid =?
Release of virion
Clinical Findings
Incubation period
1-4 days
Clinical Findings
TOF
clinical manifestation will show after 4days
True
Clinical Findings
Orthomyxoviridae
Clinical manifestation are specific or non/specific?
Non-specific
Clinical Findings
what are the clinical manifestation
- Fatigue
- Stuffy nose
- Sore throat
- Headache
- Diarrhoea/vommittin
- Prolonged fever
- Coughing
- Muscle pains and aches
Clinical Findings
chills, headache, and dry cough foilowed closely by high fever, generalized muscular aches, malaise, and anorexia.
Influenza
Clinical Findings
Can be viral secondary bacterial, or a combination of the two (viral and bacterial pneumonia)
Pneumonia
Clinical Findings
Bacterial pathogens for Pneumonia are most often?
- Staphylococcus aureus
- Streptococcus pneumoniae
- Haemophilus influenza
Clinical Findings
Acute encephalopathy of children and adolescents
exposure to aspirin
Reye Syndrome
