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Press Release

For Immediate Release: May 22, 1998
Contact: CDC Media Relations (404) 639-3286

National Computer Network in Place to Combat Foodborne Illness

Detects and Traces E. Coli Strains Up to Five Times Faster

HHS Secretary Donna E. Shalala today announced completion of PulseNet, a national computer network of public health laboratories that will help rapidly identify and stop episodes of foodborne illness. The new system enables epidemiologists to move up to five times faster than previously feasible in identifying serious and wide-spread food contamination problems.

Speaking at a White House event with Vice President Al Gore, Secretary Shalala said the new national PulseNet system is the latest feature of the Clinton administration's initiative to improve food safety and detect foodborne disease. She said the next step should be increased resources for food safety efforts, and legislation to help ensure the safety of imported foods.

"America's food supply is unmatched in quality and quantity, but we face new challenges as our food distribution systems change and as new pathogens emerge and familiar ones grow resistant to treatment," Shalala said. "PulseNet will help us keep ahead of these challenges. We also need action by Congress to increase food safety resources at CDC and the Food and Drug Administration, and to pass legislation that will give FDA authority to ensure the safety of imported foods."

PulseNet is based on a molecular technology called pulsed-field gel electrophoresis (PFGE), standardized by HHS' Centers for Disease Control and Prevention, to identify distinctive "fingerprint" patterns of E. coli O157:H7. Under the networked computer system officially launched today, public health laboratories throughout the country can use this technology and share information via the Internet to determine when foodborne disease outbreaks are occurring. In this way, epidemiologists are able to rapidly assess whether a widespread food incident is underway, and can more quickly trace the source of the problem.

"Foods reaching American tables today are produced, processed and distributed very differently from even a decade ago. Food from a single source may be rapidly distributed to communities across the nation, making it more difficult to detect a disease outbreak caused by a contaminated food product," Secretary Shalala said. "PulseNet combines the latest in microbiology and computer technology to quickly detect whether illness occurring in many different locations, during the same timeframe, are linked to a common food source."

The PFGE technology underlying PulseNet was first used by CDC in a foodborne illness outbreak in 1993, but lack of computer networking prevented the rapid response that is possible today. Computer networking began with public health labs in four states in 1995, and has recently been expanded to 12 additional states.

Today's announcement marks the ability of the four key area laboratories, as well as U.S. Department of Agriculture and Food And Drug Administration labs, to link directly with the CDC computer server and gain direct access to the CDC database, allowing rapid direct exchange of information.

"With these computer links, the PulseNet system is in place, and its full technical potential is available to help protect Americans from foodborne illness," Secretary Shalala said.

The PulseNet computer network grew out of the experience of public health experts when investigating a large outbreak of foodborne illness caused by a deadly strain of bacteria, E.coli 0157:H7, in 1993. Today, what takes as little as 48 hours with PulseNet took weeks in 1993 as investigators searched for the common food source of the outbreak--ultimately determined to be hamburger patties served at a large chain of regional fast food restaurants.

In the 1993 outbreak, CDC scientists performed the relatively new technique of DNA "fingerprinting" and determined the strain of E. coli O157:H7 found in patients matched the strain found in hamburger patties ­ the source of the outbreak. The prompt recall of the suspected ground beef patties prevented an estimated 800 additional illnesses in 1993; however, more than 700 persons became ill and 4 children died in the outbreak. The process of matching the bacterial strains in multiple communities was slowed because public health labs in multiple states could not quickly share information about their samples of E. coli. Now, with PulseNet, labs can instantly determine if a sample of the E. coli strain causing illness in their communities is also causing illness in communities next door or across the country.

"PulseNet can help public health experts recognize that foodborne illness occurring at the same time but in widely dispersed locations are from the same strain, and may be from a common exposure," said acting CDC Director Claire Broome, M.D. "By matching bacteria subtype patterns, we can detect nationwide outbreaks quickly and better direct public health actions."

Because bacteria replicate themselves by dividing in two, the next generation and many after have the same or nearly the same genetic makeup as the parent bacterium. The similarity of genetic materials over generations makes this an excellent tool to identify outbreaks from a common source, including food. Today PulseNet participants perform DNA fingerprinting on E. coli O157:H7 isolates. In the near future, another bacterium that is an important cause of foodborne illness, Salmonella serotype Typhimurium, will be added to PulseNet. Over time, CDC will set up additional databases of DNA fingerprints for other bacteria that can cause illness through food.

Federal food safety agencies worked with the Association of State and Territorial Public Health Laboratory Directors in creating PulseNet. In 1995, CDC began to set up PulseNet with state public health laboratories in Massachusetts, Minnesota, Texas and Washington, which are designated area laboratories and provide PulseNet services to states in their region. In addition, USDA and FDA have come on-line.

Additional laboratories are joining CDC's PulseNet. In addition to the four area laboratories directly linked to CDC, other labs connected to PulseNet include those from California, Colorado, Florida, Georgia, Iowa, New Hampshire, New York, Ohio, Oregon, Utah, Virginia and Wisconsin.


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