This continuing series will explore different diseases to show the science behind how disease-causing organisms affect the body. Microorganisms have plagued humans since the beginning of time, causing debilitating diseases and even death. But how, exactly, do these microorganisms infect and cause disease? The books in this series examine various microbiological scourges that have affected humans as well as the steps that have been taken to identify, isolate, prevent, and eradicate them. Each title will outline the history and treatments of the diseases, highlighting how improvements in prevention and treatment techniques have affected the disease's impact on the world population. Encephalitis--an inflammation of the brain that can come on suddenly and be fatal--is most commonly caused by a virus, but may also be the result of bacterial infection.