Microbiology Lecture 3

Virology

• Not cells; no organelles
• Parasites
• Small genomes
• Inert outside the host

Virus transmission

• Respiratory route, e.g. influenza
• Faecal-oral route, e.g. norovirus
• Sexual, e.g. herpes simplex virus
• Breach in the skin, e.g. HIV
• Vector-borne, e.g. Dengue virus (transmitted via mosquitoes)

Virus replication

Seven steps:

1. Attachment to host cell

2. Entry

3. Transcription of virus genes into messenger RNA (mRNA)

4. Translation of virus mRNA into virus proteins

5. Genome replication

6. Assembly of proteins and genomes into virions

7. Exit from the host cell

Examples:

dsDNA  Use host machinery for transcription of mRNA, i.e. RNA polymerase II…