Outbreaks of an illness or disease either may be acute (everyone’s throat is suddenly irritated) or chronic (a common illness such as cancer is experienced among a group which has an exposure in common — such as working in the same workplace). The approach to illness concerns can depend on the onset and the nature of the concern. In applications involving chronic diseases, the approach starts with considering if the experiences of the population differ from regional and national expectations for the disease given the characteristics of the populations. A statistical analysis of variation in disease prevalence adjusted for risk factors (most often age and sex) can help determine if the experience of the affected group is different from what would be expected in the population. At the same time, a cursory review of the workplace for exposures that could be associated with the specific disease or illness can be made. If there appears to be a statistically significant difference in the study population, then more in-depth evaluations of exposure in the area of concern may be appropriate.
Disease is often a factor of genetics and the environment. We consider the nature of any diagnoses provided by healthcare providers and the nature of the environment in these types of assessments. Outbreaks that have a rapid on-set are more likely to be from environmental contaminants. The investigation of this type of event is more reliant of symptomology, workplace characteristics — especially changes and the direct measurement of the air, water or surfaces for contaminants.
