Our use of this metaphor is not intended to imply that heroin use is a physical disease with viral or organic origins.

Meyer proved that it was of viral origin.

Sometimes it is difficult for your doctor to tell if the ear infection is of viral or bacterial origin.

The viral origin of cervical cancer, first recognized in 1984, is what makes the disease a target for a vaccine.

They can resemble warts, though they have no viral origins.

E2 facilitates the binding of E1 to the viral origin of replication.

This suggests that they don't have a viral origin, unlike polyDNAvirus.

The condition tends to improve with the use of ribivirin suggesting a viral origin.

This protein domain, often found in bacterial species, is actually of viral origin.

Recent evidence is accumulating pointing to a viral origin for some head and neck cancers.