病原微生物学课件：14- viruses.ppt

1 Virology1 OUTLINEIntroduction of Viruses the structure, classification and replication Mechanisms of Viral PathogenesisLab Diagnosis of Viral Diseases Antiviral Agents and Infection Control 2 344. Viral Structure, Replication, and Classification3 What about viruses?All living things survive in a sea of viruses. -We eat and breathe billions of them regularly - There are over a million virus particles per millilitre of sea waterViruses infect our pets, our domestic food animals, wildlife, plants, everything Viral infections of animals can cross over into humans and vice versa, - zoonotic infection. Viruses play the important role in our ecosystem. - The virus in ocean have a big role in the turnover of the carbon cycle4 Virus origin in history - How old are viruses? There is no fossil record. We do have lots of early records of virus infections in pre-history. ?2009 ASM Press5 1400BC,Egyptian carving Priest The first recorded characteristic of poliomyelitis Ancient references to viral diseases 6 People prevented viral infections as long ago as 11th century without knowledge of agent.Variolation- take the skin lesions of someone with smallpox and inoculate other people with them to prevent them from getting disease. 1700s Jenner take some of cowpox and put it in a person, they will protected to get smallpox. that started immunization. 7 The beginning of virologyTobacco mosaic disease Tobacco mosaic virus Dmitri Ivanowski (1892) 8Chamberland Filter (1884) Key concept of VirusesViruses are small and filterable agents. Viruses are obligate intracellular parasites.Viruses cannot make energy or proteins independently of a host cell.Viral genomes may be RNA or DNA but not both.Viral components are assembled and do not replicate by division.9 General properties of the virusesVirion = infectious particle?2009 ASM Press10 11The size of the virusesMost viruses only can be observed by electron microscopeThe viruses