And, what will the numbers be in 2011 when the CDC releases new estimates of foodborne disease?
In 1999 the CDC using FoodNet estimated that foodborne diseases caused approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. These numbers are cited as frequently as we also hear the phrase: “We have the safest food supply in the world.”
In 1999 known pathogens accounted for an estimated 14 million illnesses, 60,000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, were responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents accounted for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths.
The CDC qualified the above estimates by noting that the analysis suggested unknown agents account for approximately 81% of foodborne illnesses and hospitalizations and 64% of deaths. The CDC also noted several assumptions that were used to quantify the data. The first assumption concerned the degree of underreporting of bacterial and viral disease. The second assumption concerned the frequency of foodborne transmission for individual pathogens. And, the third assumption concerned the frequency of acute gastroenteritis in the general population.
In 2009 the CDC using FoodNet found a total of 17,468 laboratory-confirmed cases of infection were identified. In comparison with the first 3 years of surveillance (1996-1998), sustained declines in the reported incidence of infections caused by Campylobacter, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC) O157, Shigella, and Yersinia were observed. The incidence of Vibrio infection continued to increase. Compared with the preceding 3 years (2006–2008), significant decreases in the reported incidence of Shigella and STEC O157 infections were observed.
The coming 2011 estimates are expected to be more refined – primarily due to ten more years of FoodNet data. The numbers are also expected to be adjusted downward – possibly limiting, or eliminating norovirus – as norovirus accounted to a large percentage of the previous estimates. In addition, the continued decease in actual bacterial illnesses, as shown in the 2009 FoodNet data, should also show additional declining numbers.
It will be most interesting to see which groups claim victory over the numbers or how the data is explained – 2011 should be interesting.