(1) Orthomyxoviridae Flashcards by Geno Alinsub

what is the common MOT for the family of orthomyxo, paramyxo, and rubella virus?

inhalation of contaminated respiratory droplets, large aerosol droplets

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orthomyxo, paramyxo, and rubella virus shows clinical manifesttion when it infects the?

Upper respiratory tract infection

sometimes lower, or viremia (disseminated clinical picture)

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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)

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what is the unique characteristic of Orthomyxoviridae?

Genetic reassrotment

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why reoccurence of flu is possible for orthomyxoviridae?

Genetic reassortment (it creates new strain of virus every time)

mas malala pag flu season!

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characteristic of Orthomyxoviridae

Spherical in shape (100-120nm in diameter)
Single stranded, Negative-sense RNA
Enveloped
Segmented
Helical
Replication: Cytoplasm

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Orthomyxoviridae

Cell is coinfected by a 2 difference viruses of given type and forming a new strain

Genetic Reassortment

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Orthomyxoviridae

Transmission

Direct contact or respiratory droplets

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Orthomyxoviridae

Disease

influenza

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Orthomyxoviridae

how many immunologic types are there in influenza

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Influenza immunologic types

enumerate the 4 types

Influeza A, B, C, and D

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Influenza immunologic types

most and best characterized

all of the characteristics studied are from this type

Influenza A

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Influenza immunologic types

Only known to cause flu pandemic

Influenza A

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Influenza immunologic types

Most stable; antigenically stable

Influenza C

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Influenza immunologic types

Not associated with human infection

Influenza C and D

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Influenza immunologic types

also antigenically stable
Not associated with human infection

Influenza D

or C (but C is MOST stable)

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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)

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Structure of virus

associates with the viral RNA to form the ribonucleon protein (vRNPs)

Nuceleoprotein (NP)

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Structure of virus

what is used to classify the influenza viruses

NP and M1

no cross reactivity with other structural protein

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Structure of virus

forms the viral nucelocapsid

vRNPs (viral ribonucleoprotein complexes)

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Structure of virus

Small protein (small sabi ni maam)

Responsible for transcription and replication of virus

RNA Polymerase (PB1, PB2, PA)

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Structure of virus

Make the inner lining of the envelope

Matrix Protein 1

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Structure of virus

Promote the assembly of the virion

Matrix Protein 1

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Structure of virus

Responsible for the uncoating of the virion

Matrix Protein 2

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# 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

1. Virus type 2. Place of virus (isolated) 3. Strain number 4. Year isolated 5. 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

Orthomyxoviridae # Laboratory Diagnosis recommended specimen

Flocked swabs - Higher yield for epithelial cell

what are the 3 procedures that can be done for laboratory diagnosis of orthomyxoviridae

1. RT-PCR 2. Culture 3. 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

1. Bindinf to the target cell 2. Taken inside the cell 3. Hydrogen Ions will enter the endosomes of the virion 4. Relase of the content into the cytoplasm 5. Protein synthesis 6. Replication 7. Assembly 8. Budding 9. 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

Orthomyxoviridae # Clinical Findings 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 v**iral 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

(1) Orthomyxoviridae Flashcards

(92 cards)