Error catastrophe

Error catastrophe is the extinction of an organism (often in the context of microorganisms such as viruses) as a result of excessive mutations. Error catastrophe is something predicted in mathematical models and has also been observed empirically.

Like every organism, viruses 'make mistakes' (or mutate) during replication. The resulting mutations increase biodiversity among the population and help subvert the ability of a host's immune system to recognise it in a subsequent infection. The more mutations the virus makes during replication, the more likely it is to avoid recognition by the immune system and the more diverse its population will be (see the article on biodiversity for an explanation of the selective advantages of this). However, if it makes too many mutations, it may lose some of its biological features which have evolved to its advantage, including its ability to reproduce at all.