A disease outbreak is an occurrence of cases that are in excess of what would be expected within a community, geographical area or season. These events can be caused by infectious agents that spread directly from person to person or through a vector, such as ticks, birds or mosquitoes. They can have a localized or global impact and are maintained by human behaviours that allow the infection to spread.
Foodborne illness outbreaks are a leading cause of infectious disease in the United States. These outbreaks are typically initiated by identifying a cluster of illnesses in which the pathogen, usually bacteria or toxins, is hypothesized to be associated with a common food vehicle (vehicle). Traditionally, the identification of a potential outbreak vehicle is followed by epidemiologic investigation and traceback through product and environmental sampling. However, using a sample-initiated outbreak investigation (SIROI) approach allows the pathogen/commodity pair to be identified in advance of traditional outbreak investigations through microbial subtyping.
SIROIs can also be used to identify and prioritize foods for inspection based on microbial characterization. This can help focus public health interventions and resources on areas where there is an increased risk for outbreaks.
These outbreaks were investigated with the support of state public health departments, who serve as the backbone of any multistate outbreak investigation. The authors thank them for their critical roles in collecting product and environmental samples and traceback documents, as well as epidemiologic information.