Viral disease
Disease caused by pathogenic virus invasion of host cells.
A viral disease, also known as a viral infection or virosis, occurs when pathogenic viruses invade an organism's body, with infectious virus particles (virions) attaching to and entering susceptible cells. Examples include the common cold, gastroenteritis, COVID-19, the flu, and rabies. The clinical characteristics of viruses can differ substantially among species within the same family.
- caused_by
- Pathogenic viruses
- examples
- Common cold, gastroenteritis, COVID-19, flu, rabies
- genome_types
- dsDNA, ssDNA, dsRNA, positive-sense ssRNA, negative-sense ssRNA, ssRNA-RT, dsDNA-RT
- replication_rule
- DNA viruses generally replicate in nucleus; RNA viruses in cytoplasm (exceptions: poxviruses, orthomyxoviruses, hepatitis D virus)
Lore & Background
Viral diseases are defined by the invasion of an organism's body by pathogenic viruses, with virions attaching to and entering susceptible cells. The structural characteristics of viruses, such as genome type, virion shape, and replication site, generally share the same features among virus species within the same family. For example, double-stranded DNA families include non-enveloped (Adenoviridae, Papillomaviridae, Polyomaviridae) and enveloped (Herpesviridae, Poxviridae) types, with all non-enveloped families having icosahedral capsids.
Reader's Guide
The study of viral diseases is guided by pragmatic rules derived from human-infecting virus families. As a general rule, DNA viruses replicate within the cell nucleus while RNA viruses replicate within the cytoplasm, though exceptions exist: poxviruses replicate in the cytoplasm, and orthomyxoviruses and hepatitis D virus (RNA viruses) replicate in the nucleus. Segmented genomes are found in Bunyaviridae, Orthomyxoviridae, Arenaviridae, and Reoviridae (acronym BOAR), all RNA viruses. Viruses transmitted almost exclusively by arthropods include Bunyavirus, Flavivirus, and Togavirus, with some Reoviruses also transmitted from arthropod vectors; all are RNA viruses. One family of enveloped viruses causes gastroenteritis (Coronaviridae), while all other viruses associated with gastroenteritis are non-enveloped. The Baltimore group defined multiple categories of virus: I (dsDNA), II (ssDNA), III (dsRNA), IV (positive-sense ssRNA), V (negative-sense ssRNA), VI (ssRNA-RT), and VII (dsDNA-RT).
Did You Know?
- DNA viruses generally replicate in the cell nucleus, but poxviruses replicate in the cytoplasm.
- The Hepatitis D virus has not been assigned to a family and is distinct from other human-infecting virus families.
- Viruses transmitted almost exclusively by arthropods include Bunyavirus, Flavivirus, and Togavirus, all RNA viruses.
- One family of enveloped viruses causes gastroenteritis (Coronaviridae); all other gastroenteritis-associated viruses are non-enveloped.
More in Common Infections And Diseases 1-21
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