This continuing series explores 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. Also known as the "bird flu," avian influenza is a disease that once infected only birds but has acquired the ability to infect humans with deadly results.