Step 1: Detect a Possible Multistate Outbreak

Multistate outbreaks are usually identified by PulseNet, but other public health partners also identify them and report them to CDC. PulseNet is CDC’s national laboratory network for detecting bacterial enteric (intestinal) disease outbreaks.


Multistate outbreaks are usually detected by PulseNet. PulseNet scientists look for groups of people sickened by bacteria with the same DNA fingerprint (strain). Scientists perform DNA fingerprinting on bacteria using a method called whole genome sequencing (WGS). When a group of people get sick from bacteria with the same DNA fingerprint around the same time, it’s called a cluster (possible outbreak). When an investigation shows that people in a cluster have something in common, suggesting they got sick from the same source, the group of illnesses is called an outbreak.

Public health partners

Local and state health departments and federal partners like FDA and USDA may also receive reports from sick people, healthcare providers, and others about possible outbreaks. Information from these reports is frequently shared with CDC to see if the illnesses might suggest that a multistate outbreak is happening.