Complexities of Viral Nomenclature No consistent system for naming viruses – some are named for the: associated diseases (e.g. poliovirus, rabies virus) specific type of disease they cause (e.g. hepatitis A,B,C, D, E) sites in the body that are affected or from which they were first isolated (e. g. rhinovirus and adenovirus) geographic locations in which they were first isolated (e.g. Sendai virus [Sendai, Japan] and Coxsackievirus [Coxsackie, New york]) sicentists who first discovered them (e.g. Epstein-Barr virus) way in which people imagined they were contracted (e.g. dengue, for “evil spirit” and influenza, for the “influence of bad air) combinations (e.g. Rous sarcoma virus)

Virus Classification (73) (287)

David Baltimore developed a system to classify viruses based on their genomes…The Baltimore System… VII I.dsDNA II.ssDNA III.dsRNA IV.ss (+) RNA V.ss (-) RNA VI.ss (+) RNA with DNA intermediate VII.gapped dsDNA

Extremely stable, resistant to heat, detergents and chlorination All DNA viruses except the Parvoviridae and Poxviridae are dsDNA DNA Virus Mnemonic "HHAPPPPy", -Hepadna - Herpes -Adeno -Pox -Parvo - Papilloma -Polyoma

All RNA viruses except Reoviridae are ssRNA

Range in size from nm in length Contain a head structure, which can vary in size and shape The head encloses nucleic acid and acts as the protective covering Some phages have tails attached to the phage head At the end of the tail, phages like T4 have a base plate and one or more tail fibers attached to it. Morphology

Significance of phages include: Carry virulence factors for certain bacteria Essential members of the ecosystem Contributions to understanding genetics and molecular biology Phage as Tools

Potential applications for bacteriophages in human health