imm of common cold

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IMMUNOLOGY OF

COMMON COLD


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COMMON COLD

ETIOLOGY

MECHANISM OF

INFECTION

SYMPTOMS

PREVENTION &

TREATMENT

SOLVING COMMON

COLD!!!


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COMMON COLD

Acute Viral Naso - Pharyngitis

The common cold is actually a heterogeneous group of

diseases caused by numerous viruses that belong toseveral different families.ComplicationsSinusitis, Asthma, Bronchitis, Ear

infections


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A short mild illness of the upper respiratory tract(URTI).

Early symptoms of headache, sneezing, chilliness, and

sore throat and later symptoms of nasal discharge, nasalobstruction and cough.

The severity of symptoms increases rapidly, peaking 2

3 days after infection, with a mean duration of symptomsof 710 days but with some symptoms persisting formore than 3 weeks.

COMMON COLD


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VIRUS PROPORTION OF CASES

Rhinoviruses 3050%

Corona viruses 1015%

Influenza viruses 515%Respiratory syncytial virus 5%

Para influenza viruses 5%

Adenoviruses


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TRANSMISSION OF VIRUSES

Hand contactwith secretions that containthe virus, either directly from an infected person orindirectly from environmental surfaces

Small-particle aerosols lingering in the air for anextended time

Direct hit bylarge-particle aerosols from an infectedperson.


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MECHANISM OF INFECTION


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CELL RECEPTORS OF HRVs

MAJOR MINOR


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VIRUS ENTRY & INFECTION


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INDUCTION & MAINTENANCE OF IMMUNITY


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APPEARANCE OF SYMPTOMS

Early Infection

Increase in PMN Leucocytes

Antigenic Stimulation (Viral RNA)

Trigger of Acute Phase Response -

Macrophages

Ag binding to Toll-receptors on

Macrophages

Production of Cytokines

INFLAMMATORY RESPONSE -

Symptoms

Histamine,Kinins,Interleukins

Prostaglandins


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SYMPTOMS


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Sore throatDue to action of Bradykinin and Prostaglandins onnerve endings in the AirwayCould lead to Severe throat pain


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SneezingMediated by Histamine receptors on theTrigeminal nerves


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CoughProtective ReflexFor expulsion of mucusAirwayinflammation at/below the Larynx level


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OTHER SYMPTOMS

RHINORRHOEA

- Nasal discharge - complex mix of elements derivedfrom glands, plasma cells, and plasma exudates from

capillaries

- Colour of nasal discharge and sputum is often used as aclinical markerto prescribe antibioticsnot an obviousreason in most cases


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OTHER SYMPTOMS

NASAL CONGESTION

- Due to dilation of large veins in the nasal epithelium, dueto action of Bradykinin (vasodilator mediators)

EPIPHORA (Watery Eyes)

- Usually in allergic rhinitis

- Due to obstruction of naso-lacrimal ductAccumulationof tears


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PREVENTION

WASHING HANDSA MUST!!!

Role of SupplementsZinc, Vit CNot known

Could be because of Psychological factors (Stress)


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TREATMENT

Older antihistamines (First Generation")

Non-steroidal anti-inflammatory drugs (NSAIDs)

Decongestants (Vasoconstrictors)

Cough suppressants (Narcotics)

Anticholinergics


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SOLVING COMMON COLD!!!

University of Maryland School of Medicine, the University ofWisconsin-Madison and the J. Craig Venter Institute - Reportedthe sequences for all of the 99 known strains of HRV, thehuman cold virus

A sequenced genome can also show an organism'svulnerabilities

Organisms Pathogenic Potential Ability of Recombinationwithin the host cell

Found three Broad categories of HRVsA, B, C


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SOLVING COMMON COLD!!!

REVERSING A FUNDAMENTAL CONCEPT IN

IMMUNOLOGY

Body actually has its own in-celldefense mechanism that can attack

viruses once they've entered a cell

TRIM21 proteinrecognizes Ab

bound to virustriggers cellsnatural defense mechanism

(Laboratory of Molecular Biology, Cambridge Univ.)


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REFERENCESBOOKS:

1. Common Cold (Ronald Eccles, Olaf Weber)2. Mucosal Immunology (John Bienenstock, Jiri Mestecky,Michael E. Lamm, Jerry R. McGhee, Warren Strober)

1. Mika J. Makela,Tuomo Puhakka, Olli Ruuskanen, Maija

Leinonen,Pekka Saikku, Marko Kimpima Ki, Soile Blomqvist, TimoHyypia, Pertti Arstila, 1998,Viruses And Bacteria In The EtiologyOf The Common Cold,J. Clin. Bio, 36:22, pg 539-542

2. Ron Eccles, REVIEW , Understanding the symptoms of thecommon cold and influenza,Lancet Infect Dis 2005;5: 718725, pgs.718-725

3. Franz Hofer, Martin Gruenberger, Heinrich Kowalski, HerwigMachat,Manfred Huettingert, Ernst Kuechler, And Dieter Blaas,1994, Members of the low density lipoprotein receptor familymediate cellentry of a minor-group common cold virus, Proc.Natl. Acad. Sci. USA, Vol. 91, pp. 1839-1842


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THANK YOU!!!

PRIYADARSHINI RAVINDRAN

BTB-09-32

imm of common cold

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