Foodborne Illness, USA—Unspecified Agents | CDC EID

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Volume 17, Number 1–January 2011
Research
Foodborne Illness Acquired in the United States—Unspecified Agents

Elaine Scallan,1 Comments to Author Patricia M. Griffin, Frederick J. Angulo, Robert V. Tauxe, and Robert M. Hoekstra
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Suggested citation for this article

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).

Foodborne diseases are a major cause of illness and death in the United States. In another article, we estimated that each year, major known pathogens acquired in the United States caused 9.4 million episodes of foodborne illness, resulting in 55,961 hospitalizations and 1,351 deaths (1). (Hereafter, episodes of illness are referred to as illnesses.) Although the number of illnesses caused by these pathogens is substantial, these illnesses represent only a subset of the total illnesses.

An additional proportion of foodborne illness is probably caused by a heterogeneous group of less understood agents. First, many agents that cause acute gastroenteritis are recognized as known or possible causes of foodborne illness, but because of a paucity of data, the number of agent-specific illnesses cannot be estimated. This category includes infectious agents (e.g., Aeromonas spp., Edwardsiella spp., and Plesiomonas spp.) and noninfectious agents (e.g., mushroom and marine biotoxins, metals, and other inorganic toxins). Second, some known agents may not be recognized as being transmitted in food. Detection of Clostridium difficile in retail meat products suggests that it may sometimes be transmitted by that route (2), and foodborne transmission of Trypanosoma spp. has recently been recognized in Brazil but not in the United States (3). Third, microbes, chemicals, and other substances known to be in food could at some time be shown to cause acute illness. Fourth, agents of foodborne illness continue to be discovered. Many major foodborne pathogens, e.g., Campylobacter spp. and Escherichia coli O157, were recognized only in recent decades (4,5). For some outbreaks (e.g., Brainerd diarrhea), even when specimens are obtained quickly, no causative agent can be identified (6,7). Additional agents of foodborne illness probably remain undescribed (8). This article provides estimates of foodborne gastroenteritis illnesses, hospitalizations, and deaths in the United States, other than those caused by the 31 major known pathogens considered in our companion article (1).



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).
Foodborne Illness Acquired in the United States—Unspecified Agents
Elaine Scallan,1 Patricia M. Griffin, Frederick J. Angulo, Robert V. Tauxe, and Robert M. Hoekstra
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Vol. 17, No. 1 • January 2011


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Foodborne Illness, USA—Unspecified Agents | CDC EID



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.
Foodborne Illness Acquired in the United States—Unspecified Agents
Elaine Scallan,1 Patricia M. Griffin, Frederick J. Angulo, Robert V. Tauxe, and Robert M. Hoekstra
Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA
Vol. 17, No. 1 • January 2011

Suggested Citation for this Article

Scallan E, Griffin PM, Angulo FJ, Tauxe RV, Hoekstra RM. Foodborne illness acquired in the United States—unspecified agents. Emerg Infect Dis [serial on the Internet]. 2011 Jan [date cited]. http://www.cdc.gov/EID/content/17/1/16.htm

DOI: 10.3201/eid1701.P21101



1Current affiliation: Colorado School of Public Health, Aurora, Colorado, USA.

Comments to the Authors

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Elaine Scallan, Department of Epidemiology, Colorado School of Public Health, Mailstop B119, Rm W3146, UCD-AMC Bldg 500, 13001 E 17th Pl, Aurora, CO 80045, USA; email: elaine.scallan@ucdenver.edu