Virology

Virology   

The    branch   of microbiology   that    deals with the study of viruses. It is the specialized subject which discuss about the cultivation, identification, destruction and exploration of viruses and related topics.

Branches of virology:

Based on application:

ð  Clinical virology – it deals with human pathogenic virus.

ð  Veterinary virology – it deals with animal pathogenic virus.

ð  Plant virology-      It deals with plant pathogenic virus.

Application of virology:

ð  In medical science.

ð  In veterinary science.

ð  In pharmaceutical science.

Steps in viral pathogenesis:

1. Attachment and entry within cells: Viruses usually replicate at the primary site of entry, eg. Respiratory tract, gastrointestinal tract, conjunctiva. Some viruses may be directly introduced in blood , e.g. hepatitis B virus, HIV.
2. Viral spread : After primary replication at the site of entry certain viruses spread and produce disease at a distant site, e.g. Polio virus , which enter through the gastrointestinal track but produces disease of  the central nervous system (CNS) Viraemia is the presence of virus in blood.
3. Cell tropism: Viruses exhibit organ and cell specificities due to presence of specific cell surface receptors, e.g. Enter viruses enter through the gastrointestinal tract but cause central nervous system disease.
4. Cell injury: The change depends on the virus and type of the cell.

1. Cell necrosis.
2. Proliferation of the cell followed by necrosis.
3. Proliferation of cell.
4. There is no change.

Virus shedding: The virus is shaded into the environment