Are virus strains different viruses?

Question

This question comes about from another virology question concerning the common cold (Would being infected with every kind of cold virus strain at once be a good immunization or dangerous?).

The original edit stated that there are over 200 different viruses which cause the common cold, and after reading the linked Wikipedia article, it said just under the intro panel (the bit with a representation of a virus) what I believed to confirm my initial thought, that it is virus strains not different viruses.

Well over 200 virus strains are implicated in causing the common cold, with rhinoviruses being the most common.

So I commented the fact and after editing to suit, the author responded with (emphasis mine)

@Chris Rogers How do you explain this from wiki?The common cold is a viral infection of the upper respiratory tract. The most commonly implicated virus is a rhinovirus (30–80%), a type of picornavirus with 99 known serotypes.[29][30] Other commonly implicated viruses include human coronavirus (≈ 15%),[31][32] influenza viruses (10–15%),[33] adenoviruses (5%),[33] human respiratory syncytial virus, enteroviruses other than rhinoviruses, human parainfluenza viruses, and metapneumovirus.[34] Frequently more than one virus is present.[35] In total over 200 viral types are associated with colds.[3]

I have not been able to find anything online the difference between the two (if there are any). Are the rhinoviruses, enteroviruses, metapneumoviruses etc. involved different strains of the same virus or are they different viruses all together?

Answer 1

It is often said that a common cold can be caused by more than 200 different "specific viruses" (rhinovirus, influenza virus...), which suggests 200 virus species, but there are other levels of categorization of viruses (families, genera, "types," etc.), so this can be a bit of apples and oranges situation, but in any case, 200 specific viruses does not mean 200 strains.

More than 200 different viruses are known to cause the symptoms of the common cold. (National Institute of Health)

The common cold is an upper respiratory infection that is caused by several families of viruses. Within these virus families, more than 200 specific viruses that can cause the common cold have been identified. The virus family that causes the most colds is called rhinovirus. Rhinoviruses cause up to 40% of colds, and this virus family has at least 100 distinct virus types in its group. Other important upper respiratory virus families are named coronavirus, adenovirus and respiratory syncytial virus. Since so many viruses can cause cold symptoms, development of a vaccine for the common cold has not been possible. (Harvard Medical School)

Each species of a virus can further appear as different strains.

In biology, a strain is a low-level taxonomic rank used at the intraspecific level (within a species). (Wikipedia)

For example, all different strains of influenza virus will be still called influenza virus and the detailed name will be used only for laboratory/research purposes, not for the "public."

Every year different strains of influenza virus appear, so every year a new vaccine targeted to those strains needs to be developed to be effective.