Error catastrophe refers to the cumulative loss of genetic information in a lineage of organisms due to high mutation rates.
[1] The term is most widely used to refer to mutation accumulation to the point of inviability of the organism or virus, where it cannot produce enough viable offspring to maintain a population.
This use of Eigen's term was adopted by Lawrence Loeb and colleagues to describe the strategy of lethal mutagenesis to cure HIV by using mutagenic ribonucleoside analogs.
The resulting mutations increase biodiversity among the population and can confer advantages such as helping to 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).
i.e. if and only if: This result is more popularly expressed in terms of the ratio of a:b and the error rate q of individual digits: set b/a = (1-s), then the condition becomes Taking a logarithm on both sides and approximating for small q and s one gets reducing the condition to: RNA viruses which replicate close to the error threshold have a genome size of order 104 (10000) base pairs.
Drugs have been created to increase the mutation rate of the viruses in order to push them over the critical boundary so that they lose self-identity.