GENERAL MICROBIOLOGY - T.P. Pyrog - 2004

10. VIRUSES: DISTRIBUTION AND STRUCTURE

10.5. VIRUS CLASSIFICATION

The fundamental principle of Virus Classification is the type of nucleic acid they contain. Based on this criterion, Viruses are divided into two main groups: DNA-containing and RNA-containing (DNA- and RNA-genomic). Each of these groups is subsequently divided into families, subfamilies, genera, and species, with the suffixes -viridae (family), -virinae (subfamily), and -virus (for other taxa) appended to the base names.

The primary criteria for dividing viruses into families include the Structural Features of their Nucleic Acids (single- or double-stranded, complete vs. incomplete, intact vs. fragmented), their conformation (linear vs. circular), genomic function («plus» or «minus» strand polarity), as well as the presence or absence of an outer envelope. Additional criteria used to distinguish subfamilies, genera, and species within a family include host range, antigenic Specificity, virion size and Morphology, Symmetry type and number of capsomeres in the capsid, Organ and tissue tropism, transmission routes, geographical distribution, and the clinical manifestation of viral diseases, among others.

DNA-genomic viruses are grouped into 7 families, while RNA-genomic viruses comprise 13 families (Table 10.2). Table 10.2 also lists the subfamilies (where applicable), recognized genera, and the most characteristic diseases caused by members of each family.

Class="center">Table 10.2

Virus Classification

Family		Subfamily		Genus		Representatives
RNA-genomic viruses (13 families)
Picornaviridae				Enterovirus, Cardiovirus Rhinovirus, Aphthovirus		Polioviruses, hepatitis A virus, acute respiratory and intestinal infections, rhinitis, myocarditis
Caliciviridae		—		—		Gastroenteritis viruses
Togaviridae		—		—		Equine encephalitis virus
Flaviviridae		—		—		Tick-borne encephalitis virus, yellow fever virus, rubella virus
Orthomyxo- viridae		—		Influenzavirus		Influenza Viruses A, B, C
Paramyxo- viridae		—		Paramyxovirus, Morbillivirus, Pneumovirus		Parainfluenza viruses, mumps virus, measles virus
Arenaviri- dae		—		—		Lassa virus, lymphocytic choriomeningitis virus
Coronaviri- dae		—		—		Acute respiratory disease viruses
Bunyaviridae				Bunyavirus, Phlebovirus, Nairovirus, Uukuvirus		Crimean-Congo hemorrhagic fever virus
Retroviridae		Oncovirinae				Oncogenic type B, C, and D viruses (breast Cancer, leukemias, lymphosarcoma), HUMAN IMMUNODEFICIENCY VIRUS
		Spumavirinae		Spumavirus
		Lentivirinae		Lentivirus
Reoviridae				Reovirus, Orbivirus Rotavirus, Phytoreovirus, Fijivirus, Cypovirus		Acute respiratory and intestinal infection viruses
Rhabdoviridae		—		Lyssavirus, Vesiculovirus		Rabies virus, vesicular stomatitis virus
Filoviridae		—				Ebola virus, Marburg virus
DNA-genomic viruses (7 families)
Poxviridae	Chordopoxvirinae		Orthopoxvirus, Avipoxvirus, Suipoxvirus, Parapoxvirus, Capripoxvirus, Leporipoxvirus		Poxviruses, dermatotropic viruses
	Entomopoxvirinae		—
Herpesviridae	Alphaherpes- viridae		—		Herpes simplex and varicella-zoster viruses
	Betaherpes- viridae		—		Cytomegalovirus
	Gammaherpes- viridae		—		Oncogenic lymphotropic Epstein-Barr and Marek's disease viruses
Adenoviridae			Mastadenovirus, Aviadenovirus		Adenoviruses causing acute respiratory diseases, Conjunctivitis, Pneumonia
Papovaviridae	—		Papillomavirus, Polyomavirus		Papilloma and polyoma viruses, simian vacuolating virus (SV40)
Hepadnaviridae	—		—		Hepatitis B virus
Parvoviridae			Densovirus, Parvovirus, Dependovirus		Parvovirus B19 (causes infectious erythema, hemolytic anemia)
Iridoviridae			Iridovirus, Ranavirus, Chloriridovirus		Fish lymphocystis viruses, African swine fever virus, insect viruses

Last update: 12/08/2026

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