Virology is the study of viruses and virus-like pathogens. This field frequently uses laboratory research to study the structure, classification, and evolution of viruses, as well as their interactions with host cells and the way other living creatures fight them. Virology also focuses on the spread of infectious disease, including threats like the common cold, rabies, yellow fever, and polio. Virologists often work with research centers, hospitals, and pharmaceutical companies to develop vaccines that help fight viral infections. More recently, virology has started to focus on using viruses or virus-like structures for medical treatments, such as mapping neurons in the brain.