This lively book offers clear information on how the thousands of viruses and bacteria can cause illness, from common infections such as colds, flu, and pink eye, to potentially fatal infections such as AIDS and HIV, hepatitis, and SARS. With age-appropriate language, the book succinctly explains the differences between viruses and bacteria, describes how viruses can mutate to become potentially more dangerous, and provides important information on how people can protect themselves from both kinds of germs.