,VIRAL INFECTIONS
• Simplest smallest infectious microorganisms
• Structure : single or double stranded, RNA or DNA, protein coat called capsid.
• DNA/RNA + capsid = nucleocapsid or core.
• Only core causes infection not other parts.
• Virus is obligate parasite.
• Tropism = when virus matches with a specific cell type and cell has receptors for it on surface.
Pathogenesis RNA retroviruses use host cell DNA to replic
Virus binds its ligand on protein coat TO a receptor on tropic cell RNA genome.
>>>
Virus penetrates cell wall and enters cytoplasm ALL viruses alter the usual metabolic and
>>> synthesis pathways of the host cell to their
Shedding of viral envelope >>
>> This results in death of host cell
Viral disintegration and incorporation of segments into host >>
DNA dispersed replicated viruses infect adjace
>>
RNA viruses remain in cytoplasm
, LATENCY
A prolonged stage of some viral infections in which the viral core is integrated within cellular component
but its presence is not detectable clinically or with the use of laboratory methods.
Reasons :
➢ Body immune system attenuates virus activity
➢ Infection is not sufficiently toxic to cause cell death in host
➢ Plays important role in carcinogenesis
,
• Simplest smallest infectious microorganisms
• Structure : single or double stranded, RNA or DNA, protein coat called capsid.
• DNA/RNA + capsid = nucleocapsid or core.
• Only core causes infection not other parts.
• Virus is obligate parasite.
• Tropism = when virus matches with a specific cell type and cell has receptors for it on surface.
Pathogenesis RNA retroviruses use host cell DNA to replic
Virus binds its ligand on protein coat TO a receptor on tropic cell RNA genome.
>>>
Virus penetrates cell wall and enters cytoplasm ALL viruses alter the usual metabolic and
>>> synthesis pathways of the host cell to their
Shedding of viral envelope >>
>> This results in death of host cell
Viral disintegration and incorporation of segments into host >>
DNA dispersed replicated viruses infect adjace
>>
RNA viruses remain in cytoplasm
, LATENCY
A prolonged stage of some viral infections in which the viral core is integrated within cellular component
but its presence is not detectable clinically or with the use of laboratory methods.
Reasons :
➢ Body immune system attenuates virus activity
➢ Infection is not sufficiently toxic to cause cell death in host
➢ Plays important role in carcinogenesis
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