Twenty years ago today marked the emergence of PulseNet, the nation-wide network of laboratories that has tracked, monitored, exposed, and prevented outbreaks of foodborne illnesses ever since.
What Is PulseNet?
The system of food distribution in the U.S. is widespread and far-reaching.
Ingredients and products from any given source can find their way to multiple states on opposite ends of the country. While cases of foodborne illness are reported to the Centers for Disease Control and Prevention (CDC), geographic location is only a small part of the puzzle in tracking, preventing, and tracing outbreaks.
This is where PulseNet comes in. PulseNet laboratories collect and share the DNA fingerprints of bacterial strains. This is done in real time and also tracks reporting rates and compares them to past trends. When patterns start emerging, for instance, a particular fingerprint is getting flagged more than usual, this alerts the CDC to the possibility of an outbreak. Prior to this, foodborne illness outbreaks either went unrecognized or were only spotted when they grew unacceptably large.
How PulseNet Works at Preventing Foodborne Illness
PulseNet is not a single program or database. Rather, it is the combined efforts that form a specific chain of events surrounding foodborne illness reporting and tracking. As the CDC explains:
- A person falls ill and goes to the doctor.
- If the doctor suspects foodborne illness, they get a sample and send it to a lab.
- If a culprit bacteria is found (for instance, Salmonella), the lab isolates it and alerts the doctor. The doctor then tells the patient and advises them on treatment options.
- Meanwhile, the bacteria sample gets sent to a local or state public health lab.
- This new lab determines the subtype of bacteria (for instance, Salmonella enteritidis) and produces a pattern of its DNA fingerprint.
- This fingerprint is uploaded into a database at the lab and to a national database at the CDC. Microbiologists and epidemiologists will review these reports and note if any unusual activity appears.
- Epidemiologists will interview patients to learn more about the illness or gather clues that can narrow down the source of the foodborne bacteria.
- Meanwhile, the microbiologists look through the database for matching patterns. Finding multiple patients whose samples show the same fingerprint is a big clue that they are part of a singular outbreak.
- When a group of matching patterns, called a cluster, is identified, local, state, and national agencies become moved into action to identify the source of the outbreak. This is done through interviews, molecular analysis, epidemiological studies, and other techniques.
- When the source is identified, protection and preventative measures are developed and put into place.
PulseNet By the Numbers
- PulseNet tracks nine different bacteria including, Campylobacter, Cronobacter, Listeria, Salmonella, Shiga-toxin E. coli, Shigella, Yersinia, Vibrio cholera, and Vibrio parahaemolyticus.
- The three most common foodborne illnesses are Salmonella, E. coli, and Listeria. From these three alone PulseNet has prevented roughly 270,000 illnesses each year.
- Every year, PulseNet detects about 1,500 clusters at local or state levels, 250 clusters that span multiple states, and confirms about 30 multistate outbreaks of foodborne illness.
- PulseNet costs roughly $7 million per year to operate but its prevention effects are estimated to save $507 million in healthcare costs and lost productivity every year. This is a 1:70 return on investment, or $70 saved for every $1 spent.
- Over its 20 year history, the investigations triggered by PulseNet have resulted in over one billion pounds of contaminated food to be withdrawn from the market.
Sources for Today’s Article:
“20 Years of PulseNet: Preventing Thousands of Illnesses and Saving Millions of Dollars,” APHL Lab Blog web site, March 15, 2016; http://www.aphlblog.org/2016/03/20-years-of-pulsenet-preventing-thousands-of-illnesses-and-saving-millions-of-dollars/.
“Pulse Net – Frequently Asked Questions,” Centers for Disease Control and Prevention web site, February 16, 2016; http://www.cdc.gov/pulsenet/about/faq.html.