classification of viruses @ classification is by two ways: 1. by structure of nucleic acid 2. by...
TRANSCRIPT
Classification of Viruses
@ Classification is by two ways: 1. By structure of nucleic acid
2. By size, envelope, capsid shape
Tobacco mosaic virus : 1st discovered in history
DNA VIRUSES
1. 3 non-enveloped families:
* Papovaviruses, * Adenoviruses
* Parvoviruses,
2. 3 enveloped families :
a) Hepadnaviruses
b) Herpesviruses c) Poxviruses
DNA strand
Papovaviruses
@ Double-stranded circular DNA.
e.g. Human papilloma-virus
Adenoviruses
@ Have Double-stranded linear DNA
@ Contain 40 antigenic types .
Parvoviruses
@ Very small, Single stranded
linear DNA.
@ 2 types of parvoviruses:
* Defective
• * Non-defective
Hepadnaviruses
@ Double-stranded
e.g Hepatitis B virus
Herpesviruses
@ Double stranded, linear DNA
e.g Herpes simplex virus
Poxviruses
@ Largest virus with a bricklike shape
e.g. Smallpox virus
RNA VIRUSES
@ 14 families: Picornavirus Calicivirus
Reovirus Flavivirus Togavirus
Retrovirus Orthomyxovirus
RNA Structure
Paramyxovirus
Rhabdovirus
Filovirus
Coronavirus
Arenavirus
Bunyavirus
Deltavirus . Double stranded RNA
Picornaviruses
@ Smallest virus in size
@ Single stranded, linear RNA within a
non-enveloped icosahedral capsid.
e.g, Poliovirus
Caliciviruses
@ Non-enveloped, icosahedral capsid.
@ Single stranded, linear, RNA.
e.g. Hepatitis E virus.
3D Calicivirus
Reoviruses
@ Non-enveloped family with two icosahedral capsid coats.
@ Double stranded , linear RNA.
e.g. Rotavirus.
Flaviviruses
@ Enveloped, icosahedral, Single stranded, linear, RNA viruses e.g. Yellow fever virus,
Togaviruses
@ Enveloped, icosahedral, Single stranded, linear, RNA family
e.g. Rubella virus
Retroviruses
@ Enveloped, icosahedral, with Single stranded linear RNA family
e.g. HIV .
Orthomyxoviruses
@ Enveloped, helical capsid and linear, Single stranded RNA.
e.g. Influenza virus
Paramyxoviruses
@ Enveloped, helical, Single stranded, linear, RNA family
e.g. Measles virus
Rhabdoviruses
@ Bullet-shaped, enveloped, with a helical, Single stranded, linear, RNA family.
e.g. Rabies virus
Filoviruses
@ Enveloped, helical, Single stranded , linear, RNA family.
e.g. Ebola virus .
Coronaviruses
@ Enveloped, helical, Single stranded , linear, RNA family.
@ "corona" refers to crown of spikes protruding from envelope.
Arenaviruses
@ Enveloped, helical, Single stranded, circular RNA family
e.g. Lassa fever virus.
Bunyaviruses
@ Enveloped, helical, Single stranded, circular, RNA family.
@ "bunya" refers to the place in Africa where it was isolated.
Deltavirus
@ Enveloped, helical, circular, Single stranded RNA family
e.g. Hepatitis delta virus (HDV)
