Foodborne outbreaks highlight need for intensive surveillance efforts

IDC NY 2011

NEW YORK — Several high-profile foodborne illness outbreaks in recent years — including the Escherichia coli outbreak in Germany earlier this year — have highlighted how important timely reporting can be in quelling outbreaks.

Infectious Diseases in Children Editorial Board member Larry K. Pickering, MD, discussed the E. coli outbreak in Germany and provided an overview of foodborne illness during a lecture held here at the 24th Annual Infectious Diseases in Children Symposium.

Pickering said there have been about 1,000 reported disease outbreaks, 48 million illnesses, 128,000 hospitalizations and 3,000 deaths from foodborne illness in the United States alone since records on foodborne illnesses have been kept.

Larry K. Pickering

“Most foodborne illnesses occur in people who are not part of recognized outbreaks,” he said. “For every one person who has a recognized foodborne illness, there are about 26 people who have illnesses that are not recognized.”

Noteworthy highlights

Pickering drew attention to emerging infections linked to raw milk in recent years, including Campylobacter, Listeria and Shiga toxin-producing E. coli (STEC) O157. He also noted six myths associated with raw milk, including:

• Raw milk is healthier and more nutritious than pasteurized milk.
• Drinking raw milk can prevent or cure diseases such as asthma, allergies, heart disease or cancer.
• Milk is safe as long as it is labeled “organic.”
• Milk and raw milk products such as soft cheeses and yogurts are safe if they come from healthy animals.
• If animals are raised in sanitary conditions on humane farms, this ensures that their milk is safe.
• Drinking raw milk may not be safe, but no harm will come from eating products (cheeses, yogurts) made from raw milk.

Pickering highlighted data on the percent change in incidence of laboratory-confirmed illness between 2006-2007 and 2009, which are the most recent data. The biggest decreases were observed in Shigella and STEC O157, and the biggest increases were observed in Vibrio infections.

“The rest have stayed relatively the same,” he said. “Depending on whether you are an optimist or pessimist, you can say, ‘Well, they stayed the same, so that’s good,’ or you can say, ‘With the systems we have, they should all be decreasing.’”

Surveillance systems

Pickering said there are ways that federal health officials track outbreaks, including the Foodborne Diseases Active Surveillance Network (FoodNet). Started in 1996, FoodNet is a collaborative program between the CDC, 10 state health departments, the Food Safety and Inspection Service of the US Department of Agriculture and the FDA that collects data on diseases caused by nine pathogens commonly transmitted by food and for post-diarrhea pediatric hemolytic uremic syndrome (HUS).

FoodNet data indicated that among 479 outbreaks with a confirmed single agent, 49% were norovirus and 23% were Salmonella. Poultry (15%), beef (14%) and finfish (14%) were the foods most likely to cause infection, according to Pickering. He added that hospitalizations are most often triggered by: Salmonella (62%), STEC (17%) and norovirus (7%).

“Salmonella, Listeria, and STEC caused the most fatalities,” Pickering said.

Besides rigorous monitoring by the FDA and other federal health officials, Pickering said it is important to counsel patients and families about effective measures to prevent foodborne disease, including cooking meat thoroughly and throwing away or returning any foods that are recalled.

Pickering said the need for intensive surveillance was highlighted during the German outbreak earlier this year, and he reviewed recently published data to back his conclusions.

Data recently published from Altmann and colleagues on that outbreak concluded that: Of the 13,400 STEC cases with available data, the delay from symptom onset to reporting time was 15 days from May 1 to May 15, 2011, or the early part of the outbreak, and the delay from diagnosis to notification was 2 days.

In that study, the researchers concluded: “This outbreak is a good example of circumstances in which single cases occur initially in multiple local health administrations in different federal states. In such situations, early outbreak detection and investigation become crucial to ensure early and continuous reporting to authorities at the national level.”

Disclosure: Dr. Pickering reports no relevant financial disclosures.

For more information:

• Altmann M. Emerg Infect Dis. 2011;17:1906-1909.
• Pickering LK. Food-borne diseases. Presented at: the 24th Annual Infectious Diseases in Children Symposium; Nov. 19-20, 2011; New York.

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