[Show abstract][Hide abstract] ABSTRACT: On 23 May 2011, CDC identified a multistate cluster of
Heidelberg infections and two multidrug-resistant (MDR) isolates from ground turkey retail samples with indistinguishable pulsed-field gel electrophoresis patterns. We defined cases as isolation of outbreak strains in persons with illness onset between 27 February 2011 and 10 November 2011. Investigators collected hypothesis-generating questionnaires and shopper-card information. Food samples from homes and retail outlets were collected and cultured. We identified 136 cases of
Heidelberg infection in 34 states. Shopper-card information, leftover ground turkey from a patient's home containing the outbreak strain and identical antimicrobial resistance profiles of clinical and retail samples pointed to plant A as the source. On 3 August, plant A recalled 36 million pounds of ground turkey. This outbreak increased consumer interest in MDR
infections acquired through United States-produced poultry and played a vital role in strengthening food safety policies related to
and raw ground poultry.
No preview · Article · Apr 2015 · Epidemiology and Infection
[Show abstract][Hide abstract] ABSTRACT: The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0-∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.
No preview · Article · Apr 2015 · Epidemiology and Infection
[Show abstract][Hide abstract] ABSTRACT: In August 2014, PulseNet, the national molecular subtyping network for foodborne disease surveillance, detected a multistate cluster of Salmonella enterica serotype Newport infections with an indistinguishable pulse-field gel electrophoresis (PFGE) pattern (XbaI PFGE pattern JJPX01.0061). Outbreaks of illnesses associated with this PFGE pattern have previously been linked to consumption of tomatoes harvested from Virginia's Eastern Shore in the Delmarva region and have not been linked to cucumbers or other produce items. To identify the contaminated food and find the source of the contamination, CDC, state and local health and agriculture departments and laboratories, and the Food and Drug Administration (FDA) conducted epidemiologic, traceback, and laboratory investigations. A total of 275 patients in 29 states and the District of Columbia were identified, with illness onsets occurring during May 20-September 30, 2014. Whole genome sequencing (WGS), a highly discriminating subtyping method, was used to further characterize PFGE pattern JJPX01.0061 isolates. Epidemiologic, microbiologic, and product traceback evidence suggests that cucumbers were a source of Salmonella Newport infections in this outbreak. The epidemiologic link to a novel outbreak vehicle suggests an environmental reservoir for Salmonella in the Delmarva region that should be identified and mitigated to prevent future outbreaks.
Full-text · Article · Feb 2015 · MMWR. Morbidity and mortality weekly report
[Show abstract][Hide abstract] ABSTRACT: Background: Cyclospora cayetanensis is a parasite that can cause a prolonged or remitting/relapsing diarrheal illness. U.S. outbreaks of cyclosporiasis, since the mid-1990s, have been linked to various types of imported fresh produce. In late June 2013, public health officials in Iowa and Nebraska began receiving reports of laboratory-confirmed cases of cyclosporiasis not associated with international travel. A total of 631 such cases, with onset dates during JuneAugust, were reported by 25 states; 497 (79%) of the cases were from Iowa, Nebraska, and Texas.
Methods: FDA, State and Local officials reviewed distribution records for pertinent food items identified in epidemiologic investigations. An environmental investigation was conducted at the processing facility and farms.
Results: In Iowa and Nebraska, restaurant-associated cases were linked to a bagged salad mix (iceberg and romaine lettuces, carrots, and red cabbage) from Taylor Farms, Guanajuato, Mexico. The environmental investigation conducted by FDA, in conjunction with CDC, industry and Mexican officials, at the processing facility and selected growing areas in Guanajuato found no clear sources of Cyclospora or routes of contamination at the locations that were visited; environmental samples collected by FDA, CDC and Taylor Farms tested negative for Cyclospora. Epidemiologic and traceback investigations for several case clusters in Texas pointed to cilantro harvested from Puebla, Mexico, although a single processor or farm could not be identified.
Conclusion: In 2013, at least two unrelated outbreaks of cyclosporiasis occurred, which were linked to different types of produce from different regions of Mexico. As with previous outbreaks, the sources and routes of contamination of these food items were not identified. To reduce the risk for future outbreaks of cyclosporiasis, investigations to determine what leads to contamination of produce and novel molecular methods to detect and link cases to each other and to food vehicles/sources are needed. Mexico is working with the firms to identify any areas for concern and take necessary corrective actions.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND:
Salmonella causes approximately 1.2 million infections and 400 deaths annually in the United States. On June 13, 2013, PulseNet, a national molecular subtyping network for foodborne disease surveillance, identified a cluster of human infections of Salmonella Heidelberg with indistinguishable genetic fingerprints. States and CDC initiated an investigation to identify the source and prevent additional illnesses.
We defined a case as illness with an outbreak strain with onset March 1, 2013–present. Our investigation included collection of patient exposures and comparison to a population survey, isolate testing for antimicrobial resistance, and traceback and culture of retail chicken. United States Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) conducted intensified Salmonella testing at four production facilities.
We identified 403 case-patients in 23 states and Puerto Rico; 40% (128/318) were hospitalized. A higher percentage (82% [51/61]) consumed chicken prepared at home than reported in the 2006-2007 FoodNet Population Survey, (65%, p-value <0.002); 80% (16/20) reported eating Foster Farms brand chicken. One sub-cluster was linked to Foster Farms-sourced rotisserie chicken from a single store location which subsequently recalled more than 23,000 units of rotisserie chicken products. Chicken products collected from Foster Farms facilities, Foster Farms retail chicken samples, and leftover case-patient food yielded the outbreak strains. Case-patient and poultry isolates were resistant to combinations of seven different antimicrobials, with 50 exhibiting multidrug resistance. On October 17, 2013, USDA-FSIS issued an alert about chicken from three Foster Farms facilities, reminding consumers to properly handle raw poultry. On October 11, 2013, Foster Farms began implementing process enhancements.
This multidrug resistant Salmonella outbreak, in which epidemiologic, traceback, and laboratory evidence identified Foster Farms chicken as the source, highlights the need for more rigorous Salmonella control in raw chicken products. In response, Foster Farms implemented measures to decrease Salmonella burden in chicken parts, which may stimulate nationwide adoption of more stringent standards by other producers.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: During June—August 2013, a multistate outbreak including 631 cyclosporiasis cases was reported to CDC. Most cases occurred in Iowa (140), Nebraska (87), and Texas (270). In Iowa and Nebraska, most illness onsets occurred during June, and were associated with consumption of pre-packaged salad mix containing lettuce, cabbage, and carrots. Most Texas patients had illness onsets during July. These temporal differences suggested that a different food vehicle might be causing illnesses in Texas. State health department-administered questionnaires identified multiple Texas clusters: of the two largest, Cluster 1 comprised patients from a small town (Town X), and Cluster 2 included patients who ate at a single restaurant (Restaurant A) in a different town during the incubation period. We investigated these clusters to identify possible additional contaminated food vehicles.
METHODS: Cases were defined as gastrointestinal illness in persons between June 1-August 31, 2013 with Cyclospora in stool and without international travel ≤2 weeks before illness onset. We interviewed Cluster 1 case-patients about foods eaten ≤14 days before illness onset and compared results with 2006–2007 New Mexico Foodborne Diseases Active Surveillance Network (FoodNet) Population Survey data. We conducted a case-control study with Cluster 2, including case-patients who ate at Restaurant A during July 6–16, 2013, and Restaurant A meal date-matched controls reporting no diarrhea ≤14 days afterwards. Menu-specific questionnaires were administered to gather meal consumption data and ingredient-level analyses were performed.
RESULTS: The seven Cluster 1 patients were significantly more likely to have consumed fresh cilantro (odds ratio [OR]:18.7; 95% confidence interval [CI]:2.2-863.4) and lemon (OR:11.2; 95% CI: 1.4-516.9) than FoodNet respondents. We interviewed 21 Cluster 2 case-patients and 65 controls. Eating fresh cilantro (matched OR [mOR]:19.8; CI:4.0–>999), onions (mOR:15.3; CI:2.1-697.7), and tomatoes (mOR:5.5; CI:1.1-54.1) from Restaurant A was significantly associated with illness. Of these, only cilantro was consumed by all Cluster 2 case-patients. Additionally, of the four salsas prepared at Restaurant A, three containing uncooked cilantro were significantly associated with illness (hot salsa mOR:8.0; CI:2.3-31.4; side salsa mOR:5.7; CI:1.6-23.7; fire salsa mOR:3.5; CI:1.1-12.7), while salsa containing cooked cilantro was not (salsa ranchera mOR:6.0; CI:0.7-75.2).
CONCLUSIONS: Cilantro was the likely source of illnesses among patients in Texas Cluster 2. Although these illnesses occurred soon after identification of a multistate outbreak linked to pre-packaged salad mix, these investigations indicate that the large increase in cyclosporiasis illnesses during summer 2013 were caused by at least two different food vehicles.
[Show abstract][Hide abstract] ABSTRACT: SUMMARY We investigated an outbreak of 396 Salmonella enterica serotype I 4,5,12:i:- infections to determine the source. After 7 weeks of extensive hypothesis-generation interviews, no refined hypothesis was formed. Nevertheless, a case-control study was initiated. Subsequently, an iterative hypothesis-generation approach used by a single interviewing team identified brand A not-ready-to-eat frozen pot pies as a likely vehicle. The case-control study, modified to assess this new hypothesis, along with product testing indicated that the turkey variety of pot pies was responsible. Review of product labels identified inconsistent language regarding preparation, and the cooking instructions included undefined microwave wattage categories. Surveys found that most patients did not follow the product's cooking instructions and did not know their oven's wattage. The manufacturer voluntarily recalled pot pies and improved the product's cooking instructions. This investigation highlights the value of careful hypothesis-generation and the risks posed by frozen not-ready-to-eat microwavable foods.
No preview · Article · Aug 2013 · Epidemiology and Infection
[Show abstract][Hide abstract] ABSTRACT: Foodborne diseases cause an estimated 48 million illnesses each year in the United States, including 9.4 million caused by known pathogens. Foodborne disease outbreak surveillance provides valuable insights into the agents and foods that cause illness and the settings in which transmission occurs. CDC maintains a surveillance program for collection and periodic reporting of data on the occurrence and causes of foodborne disease outbreaks in the United States. This surveillance system is the primary source of national data describing the numbers of illnesses, hospitalizations, and deaths; etiologic agents; implicated foods; contributing factors; and settings of food preparation and consumption associated with recognized foodborne disease outbreaks in the United States. 1998-2008. The Foodborne Disease Outbreak Surveillance System collects data on foodborne disease outbreaks, defined as the occurrence of two or more cases of a similar illness resulting from the ingestion of a common food. Public health agencies in all 50 states, the District of Columbia, U.S. territories, and Freely Associated States have primary responsibility for identifying and investigating outbreaks and use a standard form to report outbreaks voluntarily to CDC. During 1998-2008, reporting was made through the electronic Foodborne Outbreak Reporting System (eFORS). Results: During 1998-2008, CDC received reports of 13,405 foodborne disease outbreaks, which resulted in 273,120 reported cases of illness, 9,109 hospitalizations, and 200 deaths. Of the 7,998 outbreaks with a known etiology, 3,633 (45%) were caused by viruses, 3,613 (45%) were caused by bacteria, 685 (5%) were caused by chemical and toxic agents, and 67 (1%) were caused by parasites. Among the 7,724 (58%) outbreaks with an implicated food or contaminated ingredient reported, 3,264 (42%) could be assigned to one of 17 predefined commodity categories: fish, crustaceans, mollusks, dairy, eggs, beef, game, pork, poultry, grains/beans, oils/sugars, fruits/nuts, fungi, leafy vegetables, root vegetables, sprouts, and vegetables from a vine or stalk. The commodities implicated most commonly were poultry (18.9%; 95% confidence interval [CI] = 17.4-20.3) and fish (18.6%; CI = 17.2-20), followed by beef (11.9%; CI = 10.8-13.1). The pathogen-commodity pairs most commonly responsible for outbreaks were scombroid toxin/histamine and fish (317 outbreaks), ciguatoxin and fish (172 outbreaks), Salmonella and poultry (145 outbreaks), and norovirus and leafy vegetables (141 outbreaks). The pathogen-commodity pairs most commonly responsible for outbreak-related illnesses were norovirus and leafy vegetables (4,011 illnesses), Clostridium perfringens and poultry (3,452 illnesses), Salmonella and vine-stalk vegetables (3,216 illnesses), and Clostridium perfringens and beef (2,963 illnesses). Compared with the first 2 years of the study (1998-1999), the percentage of outbreaks associated with leafy vegetables and dairy increased substantially during 2006-2008, while the percentage of outbreaks associated with eggs decreased. Outbreak reporting rates and implicated foods varied by state and year, respectively; analysis of surveillance data for this 11-year period provides important information regarding changes in sources of illness over time. A substantial percentage of foodborne disease outbreaks were associated with poultry, fish, and beef, whereas many outbreak-related illnesses were associated with poultry, leafy vegetables, beef, and fruits/nuts. The percentage of outbreaks associated with leafy vegetables and dairy increased during the surveillance period, while the percentage associated with eggs decreased. Outbreak surveillance data highlight the etiologic agents, foods, and settings involved most often in foodborne disease outbreaks and can help to identify food commodities and preparation settings in which interventions might be most effective. Analysis of data collected over several years of surveillance provides a means to assess changes in the food commodities associated most frequently with outbreaks that might occur following improvements in food safety or changes in consumption patterns or food preparation practices. Prevention of foodborne disease depends on targeted interventions at appropriate points from food production to food preparation. Efforts to reduce foodborne illness should focus on the pathogens and food commodities causing the most outbreaks and outbreak-associated illnesses, including beef, poultry, fish, and produce.
Full-text · Article · Jun 2013 · MMWR. Surveillance summaries: Morbidity and mortality weekly report. Surveillance summaries / CDC
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND:
In September 2012, the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the New Mexico Environmental Department investigated an outbreak of illnesses caused by Salmonella Bredeney associated with consumption of Trader Joe’s Valencia Creamy Salted Peanut Butter (PB) manufactured by Sunland, Inc. of Portales, New Mexico.
Epidemiology: A total of 42 persons infected with the outbreak strain were reported from 20 states; 61% of cases were children <10 years old. Of 33 case-patients who completed the food exposure questionnaire, 78% reported shopping at different locations of Trader Joe’s, a major grocery chain; 100% of the cases purchased PB produced by a single manufacturer, Sunland, Inc.
Laboratory: FDA and state partners collected product samples at the manufacturer, retail locations, and case patient’s homes; additionally, FDA collected environmental samples at the manufacturer. S. Bredeney with a PFGE pattern matching the outbreak strain was isolated from opened jars of PB from case-patients’ homes, as well as from retained products and the environment at the firm. In addition, Salmonella Cerro, Meleagridis, Anatum, Mbandaka, and Kiambu were isolated from the manufacturer’s environment.
Investigation: Sunland, Inc. was identified as the sole contract manufacturer of the implicated PB. CDC, FDA, and the states collaborated with both Trader Joe’s and Sunland, Inc. to promptly recall implicated products. The FDA investigated Sunland, Inc., collecting samples, records, and production information from the firm. Investigators found multiple GMP deficiencies and determined that the firm’s internal controls were insufficient to prevent shipment of contaminated product. As a result of FDA’s investigational findings, the initial recall was later expanded to include multiple other products.
Conclusion: The combination of laboratory, investigational, and epidemiologic findings led to the rapid recall of the implicated PB and subsequent expansion to additional Sunland, Inc. products. Based on the firm’s history of violations, FDA took the additional step of suspending Sunland, Inc.’s registration to prevent additional contaminated product from reaching consumers. The collaboration between CDC, FDA, state and local public health officials, and industry partners led to prompt removal of the product and prevention of additional illnesses.
[Show abstract][Hide abstract] ABSTRACT: Non-O157 Shiga toxin-producing Escherichia coli (STEC) can cause severe illness, including hemolytic uremic syndrome (HUS). STEC O145 is the sixth most commonly reported non-O157 STEC in the United States, although outbreaks have been infrequent. In April and May 2010, we investigated a multistate outbreak of STEC O145 infection. Confirmed cases were STEC O145 infections with isolate pulsed-field gel electrophoresis patterns indistinguishable from those of the outbreak strain. Probable cases were STEC O145 infections or HUS in persons who were epidemiologically linked. Case-control studies were conducted in Michigan and Ohio; food exposures were analyzed at the restaurant, menu, and ingredient level. Environmental inspections were conducted in implicated food establishments, and food samples were collected and tested. To characterize clinical findings associated with infections, we conducted a chart review for case patients who sought medical care. We identified 27 confirmed and 4 probable cases from five states. Of these, 14 (45%) were hospitalized, 3 (10%) developed HUS, and none died. Among two case-control studies conducted, illness was significantly associated with consumption of shredded romaine lettuce in Michigan (odds ratio [OR] = undefined; 95% confidence interval [CI] = 1.6 to undefined) and Ohio (OR = 10.9; 95% CI = 3.1 to 40.5). Samples from an unopened bag of shredded romaine lettuce yielded the predominant outbreak strain. Of 15 case patients included in the chart review, 14 (93%) had diarrhea and abdominal cramps and 11 (73%) developed bloody diarrhea. This report documents the first foodborne outbreak of STEC O145 infections in the United States. Current surveillance efforts focus primarily on E. coli O157 infections; however, non-O157 STEC can cause similar disease and outbreaks, and efforts should be made to identify both O157 and non-O157 STEC infections. Providers should test all patients with bloody diarrhea for both non-O157 and O157 STEC.
No preview · Article · Jun 2013 · Journal of food protection
[Show abstract][Hide abstract] ABSTRACT: In 2012, CDC collaborated with state health and agricultural agencies and the Food and Drug Administration (FDA) to investigate an outbreak of Salmonella Bredeney infections associated with exposure to peanut products manufactured by Sunland, Inc. of Portales, New Mexico.
Full-text · Article · Feb 2013 · MMWR. Morbidity and mortality weekly report
[Show abstract][Hide abstract] ABSTRACT: Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the causal agent for more than 96,000 cases of diarrheal illness and 3,200 infection-attributable hospitalizations annually in the United States.
We defined a confirmed case as a compatible illness in a person with the outbreak strain during 10/07/2011-11/30/2011. Investigation included hypothesis generation, a case-control study utilizing geographically-matched controls, and a case series investigation. Environmental inspections and tracebacks were conducted.
We identified 58 cases in 10 states; 67% were hospitalized and 6.4% developed hemolytic uremic syndrome. Any romaine consumption was significantly associated with illness (matched Odds Ratio (mOR) = 10.0, 95% Confidence Interval (CI) = 2.1-97.0). Grocery Store Chain A salad bar was significantly associated with illness (mOR = 18.9, 95% CI = 4.5-176.8). Two separate traceback investigations for romaine lettuce converged on Farm A. Case series results indicate that cases (64.9%) were more likely than the FoodNet population (47%) to eat romaine lettuce (p-value = 0.013); 61.3% of cases reported consuming romaine lettuce from the Grocery Store Chain A salad bar.
This multistate outbreak of STEC O157:H7 infections was associated with consumption of romaine lettuce. Traceback analysis determined that a single common lot of romaine lettuce harvested from Farm A was used to supply Grocery Store Chain A and a university campus linked to a case with the outbreak strain. An investigation at Farm A did not identify the source of contamination. Improved ability to trace produce from the growing fields to the point of consumption will allow more timely prevention and control measures to be implemented.
[Show abstract][Hide abstract] ABSTRACT: SUMMARY In 2008, nationwide investigations of a Salmonella serotype Saintpaul outbreak led first to consumer warnings for Roma and red round tomatoes, then later for jalapeño and serrano peppers. In New Mexico, where there were a large number of cases but no restaurant-based clusters, the NM Department of Health and the Indian Health Service participated with CDC in individual-level and household-level case-control studies of infections in New Mexico and the Navajo Nation. No food item was associated in the individual-level study. In the household-level study, households with an ill member were more likely to have had jalapeño peppers present during the exposure period and to have reported ever having serrano peppers in the household. This report illustrates the complexity of this investigation, the limitations of traditional individual-level case-control studies when vehicles of infection are ingredients or commonly eaten with other foods, and the added value of a household-level study.
Full-text · Article · Dec 2012 · Epidemiology and Infection