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 Human viruses: what they are, how they tick and the illnesses associated with them |
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Probably one of the most common questions from newcomers to Virology. The simplest answer is no, for a few reasons, but I recognise that this answer does not address all the philosophical baggage tied up with "life" and what being alive means. At best, viruses could be considered undead. A virus can not make more of itself, or multiply, without help from the contents of living cells. Viruses are obligatory intracellular parasites. There are other agents described in these terms eg. the Chlamydiae, but their living status is less frequently questioned. Perhaps because these are capable of reproducing by cell division and then continue to grow by producing their own proteins? Viruses are assembled from many components that have been produced by the hijacked host cell - once assembled they don't continue to grow. A virus relies entirely upon the host cell's ability to create the energy necessary to perform all of the manufacturing processes. Viruses do not come with batteries included-but then nothing "alive" does! Also, a virus genome is predominantly deoxyribose nucleic acid (DNA) or ribodeoxy nucleic acid (RNA), but not both as is the case in the cells of an organism or other microbial agents. REFERENCES |