Introductory virology Chien-Ming Li MD, Ph.D

Virus: an obligate intracellular molecular parasite Obligate intracellular molecular parasites Very small and infectious: nanometer scale Genome: either of DNA or RNA

Classification of viruses 1.Type of nucleic acid: RNA or DNA 2.Capsid shape 3.Envelope: presence or absence 4.Size of viron

Viruses with double-stranded DNA Herpesviridae – Simplex herpes virus – Varicellovirus – Cytomegalovirus Adenoviridae Papillomaviridae – Pappilomavirus – Poxiviridae Orthopoxvirus

(-) Single-stranded RNA Mononegavirales – Paramyxoviridae – Bornaviridae – Rhabdoviridae – Filoviridae: Ebola virus, Marburg virus Orthomyxoviridae: Influenzavirus A, B, C Bunyaviridae: Hantavirus

(+) Single-stranded RNA Picornaviridae: Enterovirus, Rhinovirus, Hepatovirus Callciviridae: Norwalk, Hepatitis E Astroviridae Togaviridae Nidovirales – Coronaviridae:Coronavirus – Arteriviridae Flaviviridae

Reverse transcribing viruses Retroviridae – Alpharetrovirus, Epsilonretrovirus Hepadinaviridae – Orthohepadnavirus

Other viruses Single-stranded DNA Parvoviridae – Parvovirus Circoviridae Double-stranded RNA Rotavirus