Viral evolution refers to the process by which viruses change over time through genetic mutations and natural selection. These changes can occur rapidly due to the high replication rates of viruses, allowing them to adapt to new environments or hosts. This adaptability can lead to the emergence of new viral strains, which may have different characteristics, such as increased transmissibility or resistance to treatments. Factors influencing viral evolution include host immune responses, environmental pressures, and genetic recombination. Understanding viral evolution is crucial for developing effective vaccines and treatments, as it helps scientists predict how viruses might change and spread in populations.