Viruses ppt that is important to understand by the students

Viruses PowerPoint that is important to understand by the students

1. Introduction Introduction
to to
virusesviruses

2. Definition of a VirusDefinition of a Virus
Sub microscopic entity consisting
of a single nucleic acid surrounded
by a protein coat and capable of
replication only within the living
cells of bacteria, animals or
plants.

7. Definition of a VirusDefinition of a Virus
Obligate
Intracellular
Parasite

8. Virion StructureVirion Structure
Nucleic Acid
Spike
Projections
Protein
Capsid
Lipid Envelope
Virion
Associated
Polymerase

10. Virion MorphologyVirion Morphology
•Simple Structure
•Repetitive Structure
•High Level of Redundancy

11. Virus MorphologyVirus Morphology
Helical Icosahedral

12. Virus ReplicationVirus Replication
1Virus attachment
and entry
11
2Uncoating of virion
22
3Migration of
genome nucleic
acid to nucleus
33
4Transcription
5Genome replication
44
55
6Translation of virus
mRNAs
66
7Virion assembly
77
8Release of new
virus particles
88

17. Cytopathic Effect (cpe)Cytopathic Effect (cpe)
Adenovirus Herpes virus

18. Transmission of VirusesTransmission of Viruses
•Respiratory transmission
Influenza A virus
•Faecal-oral transmission
Enterovirus
•Blood-borne transmission
Hepatitis B virus
•Sexual Transmission
HIV
•Animal or insect vectors
Rabies virus

19. Virus Tissue TropismVirus Tissue Tropism
•Targeting of the virus to specific tissue
and cell types
•Receptor Recognition
CD4+ cells infected by HIV
CD155 acts as the receptor for
poliovirus

20. In vivoIn vivo Disease Processes Disease Processes
•Cell destruction
•Virus-induced changes to gene
expression
•Immunopathogenic disease

21. Acute Virus InfectionAcute Virus Infection
A
m
o
u
n
t
o
f
v
i
r
u
s
Time
Symptoms
Virus

22. Acute Virus InfectionsAcute Virus Infections
•Localised to specific site of
body
•Development of viraemia
with widespread infection of
tissues

23. PoliovirusPoliovirus

24. Viruses and Human TumoursViruses and Human Tumours
•Epstein Barr Virus
Burkitt’s Lymphoma
•Human papillomavirus
Benign warts
Cervical Carcinoma
•Human T-cell Leukaemia Virus (HTLV-1)
Leukaemia
•Hepatitis C virus
Liver carcinoma

25. Virus-induced tumoursVirus-induced tumours
Virus
Infection
Uninfected
Cell
?
[]
Uncontrolled cell
growth and tumour
formation

26. Virus-induced transformationVirus-induced transformation
Normal cells Transformed cells

27. Virus-Induced TumoursVirus-Induced Tumours
•Virus infects cell.
•Virus nucleic acid, as DNA,
integrates into cellular genome.
•Virus causes changes in cellular gene
expression.
•Uncontrolled cell multiplication and
tumour formation.

28. Treatment and Prevention Treatment and Prevention
of Virus Infectionsof Virus Infections
•Antivirals
•Vaccines and immunisation

29. Antiviral TargetsAntiviral Targets
•Attachment/Entry
•Nucleic acid replication
•Virus protein processing
•Virus maturation

30. Problems with AntiviralsProblems with Antivirals
•Identification of virus-specific
target.
•Generation of resistant variants.