Some specification not approved by the ICTV:

Strain - These are different lines of isolates of the same virus. Eg. Influenza viruses those were isolated from different geographical locations.

Type - They show different reactivity towards a positive serum sample, sometime called as serotypes (different antigenic specificity) of the same virus. Eg. Paramyxovirus type 1-9. There may also be subtypes within a particular type.

Group - These are divisions often based on nucleotide sequence similarities or origin. HIV group M (Main), N (Neither M or O), or O (Outlier). There may also be subgroups. (also called clade) within a particular group (M group HIV has A-J subgroups).

Variant - These are viruses whose phenotype differs from original wild type strain.

Origins of some viral names

Picorna: small having size in the scale of 10^-12 RNA segment

Birna: two RNA segment

Toga: wearing a robe

Rota : Wheel like

Arbo- Arthopod borne

Papilloma: infections result in warts

Adeno: infections of glands

Hepadna: hepatitis + DNA

Herp es: produce scaly lesions

Pox: p roduce pox lesions

Corona: crown like

Satellite viruses and Defective Interfering particles:

Consider viruses to be a part of ecological habitat where organisms tend to share the relationships with one another: mutualism, commensalism, symbiosis, and parasitism. Viruses also act similarly .

Satellite viruses - Viruses with separate genomes that are encapsidated inside viral particles that are produced by a “helper” virus. They also require helper virus replicative machinery to replicate their genomes.

Defective Interfering particles (DI particles) - Their genomes are derived from a helper virus. They are deletion mutants which have lost their ability to encode proteins, but retain their ability to replicate with the help of a replication machinery of other helper virus. They called defective interfering particles because they are defective in their a bility to produce proteins, and tend to interfere with the replication of helper virus by competing with the resources .