A virus family is a group of related viruses that share similar characteristics, such as genetic material and structure. These families are classified based on their properties, including the type of nucleic acid they contain (DNA or RNA) and their method of replication. Examples of virus families include Herpesviridae, which causes infections like cold sores, and Retroviridae, which includes the HIV virus. Each virus family can contain multiple genera and species, leading to a wide variety of viruses within the same family. Understanding virus families helps scientists develop vaccines and treatments, as well as track outbreaks of diseases caused by these viruses.