Why are RNA viruses much more deadly than DNAbased viruses
RNA viruses are generally considered to be more deadly than DNA-based viruses due to several reasons:
1. Mutation rate: RNA viruses have a higher mutation rate compared to DNA-based viruses. This is because the enzyme involved in copying the RNA genome, called RNA polymerase, lacks proofreading capabilities, resulting in frequent errors during replication. These errors lead to a higher rate of genetic variation, allowing RNA viruses to quickly adapt and evolve. This enables them to evade the immune system and develop resistance to antiviral drugs more rapidly.
2. Genetic diversity: The high mutation rate of RNA viruses contributes to their genetic diversity. This diversity allows RNA viruses to rapidly generate new strains or variants that can infect and cause diseases in different host species. This ability to jump species barriers makes RNA viruses more likely to cause zoonotic outbreaks, such as SARS, MERS, and COVID-19.
3. Immune evasion: RNA viruses have developed various strategies to evade the immune system. Due to their high mutation rate, they can rapidly generate mutant forms of proteins that are not recognized by antibodies produced by the immune system. They can also suppress host immune responses or directly attack immune cells, impairing the body's ability to control the infection.
4. Faster replication and higher viral loads: RNA viruses often replicate faster than DNA-based viruses, leading to higher viral loads in infected individuals. This results in a more severe infection as the virus can rapidly spread throughout the body and cause significant damage to infected tissues or organs.
It is important to note that while RNA viruses are generally more deadly, there can be exceptions, and the severity of viral infections depends on various factors, including the specific virus, host factors, and the immune response.