It was a serious lapse not to include the fact that viruses can
not by themselves carry out translation. It is one of the traditional
unique attributes of viruses.
However, using obligate intracellular parasitism is invalid- there
are many kinds of organisms, including Rickettsia and Chlamydia, which are
obligate intracellular parasites but are clearly NOT viruses. Interestingly,
historically, psittacosis and related agents were defined as viruses but
in the unique niche of being sensitive to certain antibiotics. We've
learned a lot since then.