RNA viruses are a type of virus that use ribonucleic acid (RNA) as their genetic material instead of deoxyribonucleic acid (DNA). They can infect a wide range of hosts, including animals, plants, and bacteria. RNA viruses are known for their high mutation rates, which can help them adapt quickly to changing environments and evade the immune system. Examples of RNA viruses include influenza, HIV, and coronaviruses, such as SARS-CoV-2, which causes COVID-19. These viruses can lead to various diseases, and their rapid evolution poses challenges for vaccine development and treatment strategies. Understanding RNA viruses is crucial for public health and disease prevention.