human astro virus mustafa ppt

7/24/2019 Human Astro Virus Mustafa PPT

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Presenter: M. S. Rahman

Moderator: Dr. Varsha A. Singh

Human Astro viruses

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Acute diarrhea (AD) -Two billion cases in childrenper year worldwide

Human astro virus (HAstV) third ,after rotavirus group A

(RVA) and noro virus (NoV)

Recently novel astro virus strains isolated from humans have

een associated !ith diseases other than gastroenteritis"

Introduction

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#$%&- 'irst identified y Appleton, Higgins,

adeley and osgrove

#$*+- aul and Appleton visualied astrovirus

using appropriate immunological reagentsight traditional serotypes have een identified

in humans

History

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Under 5 years old -9.9% of the 6.9 milliondeaths (2011)

e.ico ity- /0& diarrhoea episodes among +#1

children (#* months old)

2rail- 1/ cases in +331"45 - in a primary immunodeficiency unit at

Ne!castle 6eneral Hospital

hina- //& infants !ith diarrhoea in 7uhan 8pain- 1"$ 9 in children"

5orea -#3,03/ stool samples ( +331 to +33*) #"* 9

Epidemiology

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Novosiirs:- 01 (&"* 9) ;anuary to Decemer

+33%


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Family- Astroviridae

Two genera-

1.Mamoastrovirus(MAstVs)

2.Avastrovirus(AAstVs)

Classification

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{ {Mamalian Ast VIncludeBovine AstVFeline AStVHumanAstV(Genotype 1-8)

Ovine AstVMink AstVPorcine AstV

Avian Astrovirusinclude

Duck AstV1Turky Astv1 &2Avian Nephritis

Virus(ANV)

Classification based onthe host of origin

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Single-stranded, positive-sense RNA

NonenvelopedSize- 2830 nm in diameterShape-small, roundRough, hairy, irregular edge, smooth marginDistinctive five- or six-pointed star-like appearance(astron means star in Greek)

Symmetry- T=3 icosahedral symmetry studded withglobular dimeric spikes

30 vertices

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Structure of astro virus


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CapsidMultidomain protein

Conserved N-terminal RegionHighly variable C-terminalRegion

BasicDomain

S Domain P1 Domain

P2Domain AcidicDomain

Viral genome and CapsidShell

Spikes


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Linear, Single-stranded, positive-sense RNA

5-terminus is linked to a VPg protein-

Acts as a primer during RNA synthesis

-terminus has a poly!A" tract-

Nuclear e#port, translation and sta$ility o% mRNA

Genome Structure

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Viral Genome

ORF1a ORF1b ORF2

Viral nonstructuralproteins & VPg

RNA-dependentRNA polymerase

Capsidprotein


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Fecaloral route

Person-to-person contact.

Vomit and environmental surfaces (such ashand-mouth contact)

Consumption of shellfish (faecally

contaminated)

Mode of Transmission

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Attachment o% Virus to &nterocytes

&ndocytosis to host cell

'ncoating and release o% RNA into the cytoplasm

(ranslationReplication proteins

Replication

dsRNA genome!&R"

(ranscription

mRNAs)ne* ssRNA!+" genomes

(ranslation

Viral replication and Pathogenesis

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apsid protein precursor + .)/0L

Assem$ly o% ne* virus 1nhi$its complement activation

/aturation $y host e#tracellular proteases

ell destruction and release o% Virus

/aladsorption o% %luids and electrolytes

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Winter season in temperate regions

Rainy season in tropical regions

Developing countries - poor sanitation

Seasonal Variation

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Last between 2 and 4 daysGIT-watery diarrhoea, vomiting,

abdominal painsOthers-Headache, fever, anorexia

Immunocompromised and elderly -significant disease

Sign and symptoms

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Sample: FeacesElectron microscopyEnzyme immunoassays

Astrovirus Capsid ELISAReverse transcription-polymerase chainreaction (RT-PCR)

Nucleic acid dot-blot hybridization testOne step test

Lab Diagnosis

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For the qualitative detection of Astrovirus antigens

@he memrane pre-coated !ith monoclonal antiodies against

Astrovirus antigens on the test line region

sample reacts !ith the particle coated !ith anti-Astrovirus

antiodies pre-dried on the test strip

6enerate a coloured line

One step test

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Lab diagnosis

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Humoral immune response


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Control measures:Removal of common source of infection(e.g., ill food handler or contamination of a

water supply)Interruption of person-to-persontransmission.

Treatment:Patients may require fluidreplacement.

Prevention and treatment

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NO VACCINE


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Thank You

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human astro virus mustafa ppt

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