Foodborne illness acquired in the United States--unspecified agents

Abstract

Each year, 31 major known pathogens acquired in the United States caused an estimated 9.4 million episodes of foodborne illness. Additional episodes of illness were caused by unspecified agents, including known agents with insufficient data to estimate agent-specific illness, known agents not yet recognized as causing foodborne illness, substances known to be in food but of unproven pathogenicity, and unknown agents. To estimate these additional illnesses, we used data from surveys, hospital records, and death certificates to estimate illnesses, hospitalizations, and deaths from acute gastroenteritis and subtracted illnesses caused by known gastroenteritis pathogens. If the proportions acquired by domestic foodborne transmission were similar to those for known gastroenteritis pathogens, then an estimated 38.4 million (90% credible interval [CrI] 19.8-61.2 million) episodes of domestically acquired foodborne illness were caused by unspecified agents, resulting in 71,878 hospitalizations (90% CrI 9,924-157,340) and 1,686 deaths (90% CrI 369-3,338).

Figure 1

Agents that cause foodborne illness. STEC, Shiga toxin–producing Escherichia coli; ETEC, enterotoxigenic E. coli. *For most of these pathogens, the major manifestation is gastroenteritis. For some, i.e., Salmonella enterica serotype Typhi, Trichinella spp., and Vibrio vulnificus, some persons have diarrhea or vomiting, and the sign may initially look like those of gastroenteritis. †Most of these agents have major manifestations that do not typically include gastroenteritis. Diarrhea and vomiting can occur with some of these pathogens, e.g., Clostridium botulinum and hepatitis A virus, but are relatively uncommon. Only invasive Listeria monocytogenes infection, not diarrheal illness, is included in our estimates for known foodborne pathogens (1).

Figure 2

Schematic of estimates of illnesses, hospitalizations, and deaths caused by unspecified acute gastroenteritis agents. *The estimated numbers of illnesses, hospitalizations, and deaths (hereafter, illnesses refers to illnesses, hospitalizations, or deaths as appropriate) caused by the 24 known gastroenteritis pathogens (1) were subtracted to estimate the number of illnesses caused by unspecified agents. †The estimated numbers of illnesses related to travel were subtracted to estimate the number of domestically acquired illnesses. The estimates of the proportion related to travel were based on the overall weighted distribution of the proportions of illnesses that were related to travel from the 24 known gastroenteritis pathogens. ‡The estimated numbers of nonfoodborne illnesses were subtracted to estimate foodborne illnesses. The estimates of the proportion foodborne were based on the overall weighted distribution of the proportions of illnesses that were foodborne from the 24 known gastroenteritis pathogens. All estimates were based on US population in 2006.