A disease outbreak occurs when more cases of a particular infectious disease occur than would normally be expected in a community or geographical area. It can be caused by a single pathogen or multiple pathogens. People, animals, and the environment can all contribute to a disease outbreak.
A little boy in a Guinea village dies of Ebola, and the disease spreads through his family to neighbors and then beyond. The resulting global epidemic has killed more than 11,000 and affected millions of lives. But millions of deaths could be prevented each year by tackling factors like poverty, displacement, and climate change that allow diseases to spread rapidly from person to person and across countries.
The Smithsonian’s National Museum of Natural History teaches a critical science lesson about infectious disease in the exhibition “Outbreak: Epidemics in a Connected World.”
The first step in responding to an outbreak is to watch the situation on a daily basis, looking for trends and reporting them to public health officials as soon as they emerge. This is called “surveillance and early warning systems.” The next step involves confirming the diagnosis, formulating a hypothesis for the source, pathogen and method of transmission, writing an investigation report, and controlling the event by treatment and also prevention specific to the disease (e.g., callback of contaminated products, closure of the factory or food distribution center, cleaning and disinfection, education and information campaigns). Lastly, evaluating the success of these steps is important.