Weather and Climate Effects on Disease Background Levels

Because weather and climate effects may result in spatial and temporal changes in human disease incidence, it is important to consider them when determining whether disease outbreaks are due to natural causes or to bioterrorism. Some diseases (e.g., vectorborne) respond almost directly to environmental parameters. Weather conditions also may result in increased disease incidence by stressing a person's immune defenses or by causing human behaviors that result in increased exposure to disease. In addition, extreme weather events may directly impact public health. Awareness of weather and climate factors can therefore help to detect bioterrorist-induced events against a natural disease incidence background.