Biomedical subjects

Emerging Infections Program FoodNet Working Group

Publications and source records attributed to Emerging Infections Program FoodNet Working Group.

At least 19 recordsLinked to original sources

PubMed2006

Re-assessment of risk factors for sporadic Salmonella serotype Enteritidis infections: a case-control study in five FoodNet Sites, 2002-2003.

Active surveillance for laboratory-confirmed Salmonella serotype Enteritidis (SE) infection revealed a decline in incidence in the 1990s, followed by an increase starting in 2000. We sought to determine if the fluctuation in SE incidence could be explained by changes in foodborne sources of infection. We conducted a population-based case-control study of sporadic SE infection in five of the Foodborne Diseases Active Surveillance Network (FoodNet) sites during a 12-month period in 2002-2003. A total of 218 cases and 742 controls were enrolled. Sixty-seven (31%) of the 218 case-patients and six (1%) of the 742 controls reported travel outside the United States during the 5 days before the case's illness onset (OR 53, 95% CI 23-125). Eighty-one percent of cases with SE phage type 4 travelled internationally. Among persons who did not travel internationally, eating chicken prepared outside the home and undercooked eggs inside the home were associated with SE infections. Contact with birds and reptiles was also associated with SE infections. This study supports the findings of previous case-control studies and identifies risk factors associated with specific phage types and molecular subtypes.

Adolescent↗

PubMed2005

Economic cost of illness due to Escherichia coli O157 infections in the United States.

The Centers for Disease Control and Prevention (CDC) has estimated that Shiga toxin-producing Escherichia coli O157 (0157 STEC) infections cause 73,000 illnesses annually in the United States, resulting in more than 2,000 hospitalizations and 60 deaths. In this study, the economic cost of illness due to O157 STEC infections transmitted by food or other means was estimated based on the CDC estimate of annual cases and newly available data from the Foodborne Diseases Active Surveillance Network (FoodNet) of the CDC Emerging Infections Program. The annual cost of illness due to O157 STEC was $405 million (in 2003 dollars), including $370 million for premature deaths, $30 million for medical care, and $5 million in lost productivity. The average cost per case varied greatly by severity of illness, ranging from $26 for an individual who did not obtain medical care to $6.2 million for a patient who died from hemolytic uremic syndrome. The high cost of illness due to O157 STEC infections suggests that additional efforts to control this pathogen might be warranted.

Centers for Disease Control and Prevention, U.S.↗

PubMed2004

Chicken consumption is a newly identified risk factor for sporadic Salmonella enterica serotype Enteritidis infections in the United States: a case-control study in FoodNet sites.

The sources of sporadic Salmonella enterica serotype Enteritidis (SE) infections in the United States are unclear. To determine risk factors for sporadic SE infection, we conducted a population-based case-control study in 5 Foodborne Disease Active Surveillance Network surveillance areas. During the 12-month study, 396 cases of SE infection were ascertained. Among the 182 case patients and 345 controls, SE infection was univariately associated with international travel (matched odds ratio [MOR], 61; 95% confidence interval [CI], 8-447), eating undercooked eggs (MOR, 2.2; 95%CI, 1-5), and eating chicken prepared outside of the home (MOR, 2.2; 95% CI, 1.3-3.4). Multivariate analysis revealed that eating chicken outside of the home remained the only significant risk factor for illness (MOR, 2.0; 95% CI, 1.1-3.6). Chicken consumption has not previously been identified in the United States as a risk factor for SE infection. Measures to prevent SE infections include educating consumers and food handlers about food safety and interventions to decrease contamination of eggs and poultry.

Animals↗

PubMed2004

FoodNet estimate of the burden of illness caused by nontyphoidal Salmonella infections in the United States.

To determine the burden of Salmonella infections in the United States, Foodborne Diseases Active Surveillance Network (FoodNet) investigators conducted population-based active surveillance for culture-confirmed Salmonella infections during 1996-1999 at FoodNet laboratories. In addition, all clinical microbiology FoodNet laboratories were surveyed to determine their practices for isolating Salmonella. Telephone interviews were also conducted among residents of the FoodNet sites to determine the proportion of persons with diarrheal illness who sought medical care and the proportion who submitted stool specimens for bacterial culture. Using our model, we estimated that there were 1.4 million nontyphoidal Salmonella infections in the United States, resulting in 168,000 physician office visits per year during 1996-1999. Including both culture-confirmed infections and those not confirmed by culture, we estimated that Salmonella infections resulted in 15,000 hospitalizations and 400 deaths annually. These estimates indicate that salmonellosis presents a major ongoing burden to public health.

Campylobacter Infections↗

PubMed2004

Dramatic decrease in the incidence of Salmonella serotype Enteritidis infections in 5 FoodNet sites: 1996-1999.

Salmonella serotype Enteritidis (SE) emerged as the most common Salmonella serotype among infected persons in the United States during the 1980s and 1990s, with infections reaching a peak in 1995. During the past decade, farm-to-table control measures have been instituted in the United States, particularly in regions with the highest incidence of SE infection. We report trends in the incidence of SE in the 5 original surveillance areas of the Foodborne Diseases Active Surveillance Network during 1996-1999: Minnesota, Oregon, and selected counties in California, Connecticut, and Georgia. Overall, the incidence of SE decreased 46% from 1996 to 1999. The greatest decrease was in Connecticut (71%), followed by northern California (50%), Minnesota (46%), and Oregon (13%). Although SE infection remains an important public health concern, there has been a remarkable decrease in its incidence. This decrease may be a result of targeted interventions, including on-farm control measures, refrigeration, and education efforts.

Female↗

PubMed2004

Hospitalizations and deaths due to Salmonella infections, FoodNet, 1996-1999.

Nontyphoidal Salmonella causes a higher proportion of food-related deaths annually than any other bacterial pathogen in the United States. We reviewed 4 years (1996-1999) of population-based active surveillance data on laboratory-confirmed Salmonella infections from the Emerging Infections Program's Foodborne Diseases Active Surveillance Network (FoodNet), to determine the rates of hospitalization and death associated with Salmonella infection. Overall, 22% of infected persons were hospitalized, with the highest rate (47%) among persons aged >60 years. Fifty-eight deaths occurred, for an estimated annual incidence of 0.08 deaths/100,000 population. These deaths accounted for 38% of all deaths reported through FoodNet from 1996 through 1999, and they occurred primarily among adults with serious underlying disease. Although Salmonella infection was seldom listed as a cause of death on hospital charts and death certificates, our chart review suggests that Salmonella infection contributed to these deaths.

Adult↗

PubMed2004

Invasive Salmonella infections in the United States, FoodNet, 1996-1999: incidence, serotype distribution, and outcome.

Invasive Salmonella infections are severe and can be life threatening. We analyzed population-based data collected during 1996-1999 by the Foodborne Diseases Active Surveillance Network (FoodNet), to determine the incidences, infecting serotypes, and outcomes of invasive Salmonella infection. We found that the mean annual incidence of invasive salmonellosis was 0.9 cases/100,000 population and was highest among infants (7.8 cases/100,000). The incidence was higher among men than women (1.2 vs. 0.7 cases/100,000; P<.001) and higher among blacks, Asians, and Hispanics than among whites (2.5, 2.0, and 1.3 cases/100,000 population, respectively, vs. 0.4 cases/100,000; all P<.001). Seventy-four percent of cases were caused by 8 Salmonella serotypes: Typhimurium, Typhi, Enteritidis, Heidelberg, Dublin, Paratyphi A, Choleraesuis, and Schwarzengrund. Of 540 persons with invasive infection, 386 (71%) were hospitalized and 29 (5%) died; 13 (45%) of the deaths were among persons aged > or =60 years. Invasive Salmonella infections are a substantial health problem in the United States and contribute to hospitalizations and deaths.

Disease Progression↗

PubMed2004

Factors affecting surveillance data on Escherichia coli O157 infections collected from FoodNet sites, 1996-1999.

To determine the burden of illness caused by Escherichia coli O157 infections in populations in Foodborne Diseases Active Surveillance Network (FoodNet) surveillance areas, we initiated active, laboratory-based surveillance and surveyed laboratories, physicians, and the general public regarding the factors associated with the diagnosis and surveillance of infection with E. coli O157. We evaluated survey responses and site-specific incidence, outbreak, and demographic data during 1996-1999. A total of 1425 laboratory-confirmed cases of E. coli O157 infection and 32 outbreaks were reported from the 5 original FoodNet sites. The average annual incidence ranged from 0.5 cases/100,000 population in Georgia to 4.4 cases/100,000 population in Minnesota. After excluding outbreak-associated cases, the annual incidence of sporadic, laboratory-confirmed E. coli O157 infections remained relatively stable during 1996-1999, with a range of 1.9-2.3 cases/100,000 population. Regional differences in incidence partly resulted from differing physician and laboratory practices and from site-specific exposure factors (e.g., living on or visiting farms).

Adolescent↗

PubMed2004

Epidemiology of sporadic Campylobacter infection in the United States and declining trend in incidence, FoodNet 1996-1999.

Campylobacter species are a leading cause of foodborne illness in the United States, but few population-based data describing patterns and trends of disease are available. We summarize data on culture-confirmed cases of Campylobacter infection reported during 1996-1999 to the Foodborne Diseases Active Surveillance Network (FoodNet) system. The average annual culture-confirmed incidence was 21.9 cases/100,000 population, with substantial site variation (from 43.8 cases/100,000 population in California to 12.2 cases/100,000 population in Georgia). The incidence among male subjects was consistently higher than that among female subjects in all age groups. The incidence trended downward over the 4 years, with incidences of 23.6, 25.2, 21.4, and 17.5 cases/100,000 population for 1996-1999, respectively--a 26% overall decrease. This trend was sharpest and most consistent in California. Overall, we estimate that ~2 million people were infected with Campylobacter in the United States each year during this time period. Although the number of Campylobacter infections appears to have decreased in the United States during 1996-1999, the disease burden remains significant, which underscores the need to better understand how the disease is transmitted.

Campylobacter↗

PubMed2004

Trends in population-based active surveillance for shigellosis and demographic variability in FoodNet sites, 1996-1999.

Shigella is a common cause of diarrhea in the United States, and accurate surveillance is needed to determine the burden of illness that they cause. Active surveillance for culture-confirmed Shigella infection was done as part of the Foodborne Diseases Active Surveillance Network (FoodNet). A total of 4317 cases of shigellosis were reported during 1996-1999 in the original FoodNet surveillance areas. The average annual incidence was 7.4 cases/100,000 population. The incidence was similar during 1996-1998, but it declined in 1999 to 5.0 cases/100,000 population. State-to-state variability was seen in the incidence of shigellosis. Higher incidence was observed in California and Georgia. Shigella sonnei accounted for 70% of the infections, followed by Shigella flexneri (24%). Compared with other age groups, the incidence was highest among children aged 1-4 years of (36.3 cases/100,000 population). Marked demographic differences were observed between infections with S. sonnei and S. flexneri.

California↗

PubMed2004

Population-based surveillance for Yersinia enterocolitica infections in FoodNet sites, 1996-1999: higher risk of disease in infants and minority populations.

Active surveillance for laboratory-confirmed Yersinia enterocolitica (YE) infections was conducted at 5 Foodborne Diseases Active Surveillance Network (FoodNet) sites in the United States during 1996-1999. The annual incidence averaged 0.9 cases/100,000 population. After adjusting for missing data, the average annual incidence by race/ethnicity was 3.2 cases/100,000 population among black persons, 1.5 cases/100,000 population among Asian persons, 0.6 cases/100,000 population among Hispanic persons, and 0.4 cases/100,000 population among white persons. Incidence increased with decreasing age in all race/ethnicity groups. Black infants had the highest incidence (141.9 cases/100,000 population; range, 8.7 cases/100,000 population in Minnesota to 207.0 cases/100,000 population in Georgia). Seasonal variations in incidence, with a marked peak in December, were noted only among black persons. YE infections should be suspected in black children with gastroenteritis, particularly during November-February. Culturing for YE should be part of routine testing of stool specimens by clinical laboratories serving populations at risk, especially during the winter months.

Black or African American↗

PubMed2004

Laboratory practices for stool-specimen culture for bacterial pathogens, including Escherichia coli O157:H7, in the FoodNet sites, 1995-2000.

In 2000, we surveyed microbiologists in 388 clinical laboratories, which tested an estimated 339,000 stool specimens in 1999, about laboratory methods and policies for the routine testing of stool specimens for Salmonella, Shigella, Campylobacter, and Vibrio species, Yersinia entercolitica, and Escherichia coli O157:H7. The results were compared with those of similar surveys conducted in 1995 and 1997. Although these laboratories reported routinely testing for Salmonella, Shigella, and Campylobacter species, only 57% routinely tested for E. coli O157:H7, 50% for Y. entercolitica, and 50% for Vibrio species. The mean proportions of stool specimens that yielded these pathogens were as follows: Campylobacter, 1.3% of specimens; Salmonella, 0.9%; Shigella, 0.4%; and E. coli O157:H7, 0.3%. The proportion of laboratories that routinely tested for E. coli O157:H7 increased from 59% in 1995 to 68% in 2000; however, the proportion of stool specimens tested decreased from 53% to 46%. E. coli O157:H7 should be routinely sought in stool specimens submitted for microbiologic culture.

Campylobacter↗

PubMed2004

Survey of clinical laboratory practices for parasitic diseases.

To gain knowledge about laboratory testing practices for parasitic diseases, in 2000 we surveyed 562 laboratories in 9 US states, and 455 (81%) responded. Most laboratories (59%) indicated that they send specimens off site for parasite screening, and most laboratories (89%) did not routinely test fecal specimens for Cryptosporidium species, Cyclospora cayetanensis, or microsporidia, unless testing for these organisms was specifically requested by a physician. Only 39 laboratories offered serological testing for Toxoplasma gondii, and most (78%) that had their results confirmed did so at national commercial laboratories rather than a Toxoplasma reference laboratory. Because most clinical laboratories do not routinely test fecal specimens for Cryptosporidium species, C. cayetanensis, or microsporidia, physicians must request specific testing for these organisms when they are clinically suspected; because of this lack of routine testing, it is difficult to estimate the true burden of disease due to these organisms.

Animals↗

PubMed2004

Survey of physician diagnostic practices for patients with acute diarrhea: clinical and public health implications.

To understand physician practices regarding the diagnosis of acute diarrheal diseases, we conducted a survey, in 1996, of 2839 physicians in Connecticut, Georgia, Minnesota, Oregon, and California. Bacterial stool culture was requested for samples from the last patient seen for acute diarrhea by 784 (44%; 95% confidence interval, 42%-46%) of 1783 physicians. Physicians were more likely to request a culture for persons with acquired immune deficiency syndrome, bloody stools, travel to a developing country, diarrhea for >3 days, intravenous rehydration, or fever. Substantial geographic and specialty differences in culture-request practices were observed. Twenty-eight percent of physicians did not know whether stool culture included testing for Escherichia coli O157:H7; 40% did not know whether Yersinia or Vibrio species were included. These variabilities suggest a need for clinical diagnostic guidelines for diarrhea. Many physicians could benefit from education to improve their knowledge about tests included in routine stool examinations.

Acute Disease↗

PubMed2004

Physicians as food-safety educators: a practices and perceptions survey.

An estimated 4 million bacterial foodborne illnesses occur in the United States annually. Many of these illnesses can be prevented by educating the public about food-safety practices. We investigated both the role of physicians as food-safety educators and the barriers to providing food-safety information. Participants were randomly selected physicians (n=3117) practicing within the surveillance area of the Foodborne Diseases Active Surveillance Network; 1100 were included in the study. Although only 331 (30%) of 1110 respondents provided food-safety information to their patients, 524 (68%) of 769 who did not provide information expressed interest in doing so. Physicians were more likely to provide food-safety information to patients if they perceived foodborne disease to be a serious problem, perceived food-safety education as their role, felt that patients perceived them as a valuable resource for food-safety advice, or felt comfortable making food-safety recommendations. A national physician education campaign that addresses barriers in food-safety education could improve food-safety education by physicians.

Consumer Product Safety↗

PubMed2004

Burden of self-reported acute diarrheal illness in FoodNet surveillance areas, 1998-1999.

To assess trends in the burden of acute diarrheal illness, the Foodborne Diseases Active Surveillance Network (FoodNet) conducted a population-based telephone survey during 1998-1999, using a random-digit-dialing, single-stage Genesys-ID sampling method. During the 12-month study period, 12,755 persons were interviewed; after the exclusion of persons with chronic diarrheal illnesses, 12,075 persons were included in the analysis; 6% (n=645) reported having experienced an acute diarrheal illness at some point during the 4 weeks preceding the interview (annualized rate, 0.72 episodes per person-year). Rates of diarrheal illness were highest among children aged <5 years (1.1 episodes per person-year) and were lowest in persons aged > or =65 years (0.32 episodes per person-year). Twenty-one percent of persons with acute diarrheal illness sought medical care as a result of their illness. Diarrheal illness imposes a considerable burden on the US population and health care system.

Acute Disease↗

PubMed2004

Prior antimicrobial agent use increases the risk of sporadic infections with multidrug-resistant Salmonella enterica serotype Typhimurium: a FoodNet case-control study, 1996-1997.

Several strains of multidrug-resistant (MDR) Salmonella serotype Typhimurium, including MDR S. Typhimurium definitive type 104, cause almost 10% of Salmonella infections among humans in the United States. To determine the risk factors for acquiring sporadic MDR S. Typhimurium infection, we conducted a population-based, case-control study using data from the Foodborne Diseases Active Surveillance Network (FoodNet) during 1996-1997. S. Typhimurium isolates from 5 FoodNet surveillance areas (California, Connecticut, Georgia, Minnesota, and Oregon) were tested for antimicrobial resistance and phage typing. Telephone interviews were conducted with ill persons and matched control subjects. Compared with both control subjects and patients infected with pansensitive strains of S. Typhimurium, patients with MDR S. Typhimurium infection were significantly more likely to have received an antimicrobial agent, particularly an agent to which the Salmonella isolate was resistant, during the 4 weeks preceding illness onset. Prudent antimicrobial agent use among humans and among veterinarians and food-animal producers is necessary to reduce the burden of drug-resistant salmonellosis in humans.

Adolescent↗

PubMed2004

Egg consumption is the principal risk factor for sporadic Salmonella serotype Heidelberg infections: a case-control study in FoodNet sites.

To determine risk factors for sporadic Salmonella serotype Heidelberg diarrheal disease, we conducted a population-based case-control study in 5 Foodborne Diseases Active Surveillance Network (FoodNet) surveillance areas in 1996-1997. Forty-four case patients and 83 control subjects matched by age and telephone exchange were asked about exposures during the 5-day period before onset of illness in the case patient. Risk factors for infection were evaluated using conditional logistic regression analysis. Eating eggs prepared outside the home remained the only significant risk factor for illness (matched odds ratio [MOR], 6.0; 95% confidence interval [CI], 1.2-29.6). The population-attributable fraction of S. Heidelberg infections associated with eating eggs prepared outside the home was 37%. Eliminating the risk associated with out-of-home egg consumption could substantially reduce the incidence of S. Heidelberg infections. Control measures to prevent S. Heidelberg infection should include advising consumers to avoid eating undercooked eggs and educating food handlers about proper egg handling and cooking.

Adolescent↗