1. Classification of Viruses @ Classification is by two ways: 1. By structure of nucleic acid 2. By size, envelope, capsid shape Tobacco mosaic virus : 1 st discovered in history

3. DNA VIRUSE S 1. 3 non-enveloped families: * Papovaviruses, * Adenoviruses * Parvoviruses, 2. 3 enveloped families : a) Hepadnaviruses b) Herpesviruses c) Poxviruses DNA strand

5. Papovaviruses @ Double-stranded circular DNA. e.g. Human papilloma-virus

7. Adenoviruses @ Have Double-stranded linear DNA @ Contain 40 antigenic types.

9. Parvoviruses @ Very small, Single stranded linear DNA. @ 2 types of parvoviruses: * Defective * Non-defective

11. Hepadnaviruses @ Double-stranded e.g Hepatitis B virus

13. Herpesviruses @ Double stranded, linear DNA e.g Herpes simplex virus

15. Poxviruses @ Largest virus with a bricklike shape e.g. Smallpox virus

17. RNA VIRUSES @ 14 families: Picornavirus Calicivirus Reovirus Flavivirus Togavirus Retrovirus Orthomyxovirus  RNA Structure

19.  Paramyxovirus  Rhabdovirus  Filovirus  Coronavirus  Arenavirus  Bunyavirus  D eltavirus.  Double stranded RNA

21. Picornaviruses @ Smallest virus in size @ Single stranded, linear RNA within a non-enveloped icosahedral capsid. e.g, Poliovirus

23. Caliciviruses @ Non-enveloped, icosahedral capsid. @ Single stranded, linear, RNA. e.g. Hepatitis E virus. 3D Calicivirus

25. Reoviruses @ Non-enveloped family with two icosahedral capsid coats. @ Double stranded, linear RNA. e.g. Rotavirus.

27. Flaviviruses @ Enveloped, icosahedral, Single stranded, linear, RNA viruses e.g. Yellow fever virus,

29. Togaviruses @ Enveloped, icosahedral, Single stranded, linear, RNA family e.g. R ubella virus

31. Retroviruses @ Enveloped, icosahedral, with Single stranded linear RNA family e.g. HIV.

33. Orthomyxoviruses @ Enveloped, helical capsid and linear, Single stranded RNA. e.g. Influenza virus

35. Paramyxoviruses @ Enveloped, helical, Single stranded, linear, RNA family e.g. Measles virus

37. Rhabdoviruses @ Bullet-shaped, enveloped, with a helical, Single stranded, linear, RNA family. e.g. Rabies virus

39. Filoviruses @ Enveloped, helical, Single stranded, linear, RNA family. e.g. Ebola virus.

41. Coronaviruses @ Enveloped, helical, Single stranded, linear, RNA family. @ "corona" refers to crown of spikes protruding from envelope.

43. Arenaviruses @ Enveloped, helical, Single stranded, circular RNA family e.g. Lassa fever virus.

45. Bunyaviruses @ Enveloped, helical, Single stranded, circular, RNA family. @ "bunya" refers to the place in Africa where it was isolated.

47. Deltavirus @ Enveloped, helical, circular, Single stranded RNA family e.g. Hepatitis delta virus (HDV)