In 1999, I gave a talk to hundreds of farm leaders in Ottawa and told them that DNA fingerprinting – via PulseNet – would revolutionize foodborne illness outbreak investigations and that farmers better be prepared (the pic is from a 2003 awards ceremony where I was acknowledged for my outreach and extension efforts, the hair was fabulous).
Twenty years later and whole genome sequencing is even further piecing together disparate outbreaks.
Joanie Stiers of Farm Flavor writes that Michigan’s laboratory toolbox now includes whole-genome sequencing, allowing public health officials to stop the spread of foodborne illness faster than ever.
Since January of 2017, the Michigan Department of Agriculture and Rural Development (MDARD) has actively used whole-genome sequencing to precisely identify illness-causing pathogens and defend against widespread outbreaks of foodborne diseases.
“With food now being distributed worldwide, illness can be spread from anywhere in the world,” says Ted Gatesy, laboratory manager of the microbiology section at Geagley Lab, which houses the whole-genome sequencing. “Using whole-genome sequencing, an illness can be tracked, for the most part, to the point in the food chain where it originated.
The U.S. Centers for Disease Control and Prevention and state health officials are investigating potential exposures to Brucella strain RB51 (RB51) in 19 states, connected to consuming raw (unpasteurized) milk from Miller’s Biodiversity Farm in Quarryville, Pennsylvania. One case of RB51 infection (brucellosis) has been confirmed in New York, and an unknown number of people may have been exposed to RB51 from drinking the milk from this farm. This type of Brucella is resistant to first-line drugs and can be difficult to diagnose because of limited testing options and the fact that early brucellosis symptoms are similar to those of more common illnesses like flu.
The New York case is the third known instance of an infection with RB51 associated with consuming raw milk or raw milk products produced in the United States. The other two human cases occurred in October 2017 in New Jersey and in August 2017 in Texas. Those cases reported drinking raw milk from an online retailer and a Texas farm, respectively. In addition to these three confirmed cases, hundreds of others were potentially exposed to RB51 during these three incidents.
RB51 is a live, weakened strain used in a vaccine to protect cows against a more severe form of Brucella infection that can cause abortions in cows and severe illness in people. On rare occasions, cows vaccinated with RB51 vaccine can shed the bacteria in their milk. People who drink raw milk from cows that are shedding RB51 can develop brucellosis.
People who consumed raw milk or raw milk products from this dairy farm since January 2016 may have been exposed and should talk to their doctor.
People who are still within six months of the date they last consumed the raw milk are at an increased risk for brucellosis and should receive antibiotics to prevent an infection and symptoms, and should monitor their health for possible symptoms for six months. If symptoms develop, they should see their doctor immediately for testing.
Milk samples from Miller’s Biodiversity tested positive for RB51. A cow that tested positive for RB51 has been removed from the milking herd.
On December 1, 2017, PulseNet, the U.S. Centers for Disease Control’s molecular subtyping network for foodborne disease surveillance, identified a cluster of three Listeria monocytogenes clinical isolates with indistinguishable pulsed-field gel electrophoresis (PFGE) pattern combinations. These isolates were closely related to one another by whole-genome multilocus sequence typing within three allele differences (range = 0–3 alleles), indicating that the infections were likely from the same source.
CDC, the Food and Drug Administration (FDA), and state and local health departments initiated a multistate investigation. An outbreak case of listeriosis was defined as an infection with L. monocytogenes, with an isolate that was indistinguishable by PFGE and closely related by whole-genome multilocus sequence typing to the outbreak strain isolated during October–December 2017.
The cases corresponding to the three isolates were identified in Illinois, Iowa, and Michigan. Isolation dates ranged from October 15, 2017, to October 29, 2017. Patients ranged in age from 55 to 71 years (median = 69 years), and all three patients were male. All patients were hospitalized for listeriosis; no deaths were reported. PulseNet was queried routinely for new isolate matches during the investigation, and no additional cases were identified.
Interviews were conducted with all three patients or their surrogates using the standard Listeria Initiative questionnaire (1), which asks about a variety of foods consumed in the month preceding illness onset. Grocery store receipts were collected for the patient in Michigan. Review of reported exposures indicated that all three patients had consumed prepackaged caramel apples purchased from retail establishments in the month preceding illness onset. A case-case analysis was performed comparing exposure frequencies for all food items included in the Listeria Initiative questionnaire for the three outbreak-associated cases with exposure frequencies for 186 sporadic cases of listeriosis from the same states reported to CDC since 2006. Caramel apple consumption was significantly higher among patients included in the outbreak, compared with that among patients with sporadic illnesses (odds ratio = 21.7; 95% confidence interval = 2.3–infinity). None of the interviewed patients had leftover caramel apples in their home for testing.
State and local officials collected records at two of the three retail locations where caramel apples had been purchased. All three retailers sold the same brand of caramel apples (brand A). The product was packaged in a plastic clamshell containing three caramel apples, each on a stick. Caramel apples were seasonal products that were only available for a short period in the fall at two of the retail locations. However, the retail location where the Illinois patient purchased caramel apples had the product in stock at the time of the investigation. Eight packages of caramel apples were collected for testing by the Illinois Department of Public Health, but L. monocytogenes was not detected in any samples. It was not known whether the tested caramel apples were from the same lots as those consumed by the ill persons in this outbreak.
During an inspection at the caramel apple production facility, FDA reviewed records and practices and collected environmental samples for testing. No significant food safety concerns were observed. None of the environmental swabs yielded L. monocytogenes. Environmental swabs collected at a single whole apple supplier yielded L. monocytogenes, but it was not the outbreak strain. Traceback activities did not implicate a specific lot or supplier of whole apples used in brand A caramel apple production during the period of interest.
No additional outbreak-associated illnesses were identified during the investigation. In light of the limited shelf life of the product (reported by the production facility to be 15 days), it was unlikely that caramel apples consumed by ill persons in this outbreak would have still been available for purchase or in persons’ homes at the time of the investigation. Because there was no evidence to suggest an ongoing risk to the public, no public warning was issued by federal or state agencies.
Although the outbreak strain of L. monocytogenes was not isolated from caramel apples or their production environment, the epidemiologic evidence indicated that caramel apples were the suspected vehicle in this outbreak. All outbreak-associated ill persons consumed a specific brand of a relatively uncommon food product in the month before their illness onset, and all were infected with indistinguishable L. monocytogenes strains. Caramel apples were previously implicated in a large multistate outbreak of listeriosis during 2014–2015, caused by contamination of whole apples (2). Ready-to-eat food processors, including those that make caramel apples, could consider the introduction and persistence of L. monocytogenes in food production environments as a potential hazard and mitigate that risk through appropriate environmental monitoring and preventive controls (3). Further research into the control of L. monocytogenes in fresh produce, including fresh apples, might help identify prevention strategies to reduce or eliminate the pathogen in some ready-to-eat foods.
Notes from the field: Outbreak of listeriosis likely associated with prepackaged caramel apples
25.jan.19
CDC
Jessica R. Marus, MPH1; Sally Bidol, MPH2; Shana M. Altman3; Oluwakemi Oni, MPH4; Nicole Parker-Strobe, MPH2; Mark Otto, MSPH5; Evelyn Pereira, MPH5; Annemarie Buchholz, PhD5; Jasmine Huffman1,6; Amanda R. Conrad, MPH1; Matthew E. Wise, PhD1
1Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC; 2Michigan Department of Health and Human Services; 3Illinois Department of Public Health; 4Iowa Department of Public Health; 5Food and Drug Administration, Silver Spring, Maryland; 6Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee.
All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.
Flour comes from dried wheat that’s milled and not heat treated (because it messes with the gluten). Because wheat is grown in nature, Salmonella or E. coli or other nasties can be present. As Salmonella dries out it gets hardier and survives for months (or longer).
In 1957, Duncan Hines and his wife, Clara, cut a cake at the Duncan Hines test kitchen in Ithaca, N.Y.
In Nov. 2018, the U.S. Food and Drug Administration investigated recalled Duncan Hines Cake Mixes potentially linked to seven Salmonella Agbeni illnesses.
On January 14, 2019, the Centers for Disease Control reported the outbreak appeared to be over. The FDA, CDC, public health and regulatory officials in several states worked together to investigate this multistate outbreak of Salmonella Agbeni infections.
The FDA recommends consumers to not bake with or eat the recalled product. Additionally, consumers should not eat uncooked batter, flour, or cake mix powder.
The FDA advised consumers not to bake with or eat any recalled cake mix. If already purchased, consumers should throw it away or return to the place of purchase for a refund.
Consumers should always practice safe food handling and preparation measures. It is recommended that they wash hands, utensils, and surfaces with hot, soapy water before and after handling food.
FDA offers these tips for safe food handling to keep you and your family healthy:
Do not eat any raw cake mix, batter, or any other raw dough or batter product that is supposed to be cooked or baked.
Wash hands, work surfaces, and utensils thoroughly after contact with flour and raw batter or dough products.
Keep raw foods separate from other foods while preparing them to prevent any contamination that may be present from spreading. Be aware that flour or cake mix may spread easily due to its powdery nature.
According to the U.S. Centers for Disease Control, 11 people infected with the outbreak strain of Salmonella Typhimurium have been reported from eight states.
One person has been hospitalized and no deaths have been reported.
In interviews, 10 (91%) of 11 ill people reported contact with a hedgehog.
Illnesses started on dates from October 22, 2018 to December 25, 2018. Ill people range in age from 2 to 28 years, with a median age of 12. Forty-five percent are female.
The outbreak strain making people sick was identified in samples collected from three hedgehogs in two ill patients’ homes in Minnesota.
Hedgehogs can carry Salmonella germs in their droppings while appearing healthy and clean.
These germs can easily spread to their bodies, habitats, toys, bedding, and anything in the area where they live. People become sick after they touch hedgehogs or anything in their habitats.
Wash your hands
Always wash hands thoroughly with soap and water right after touching, feeding, or caring for a hedgehog or cleaning its habitat. Adults should supervise handwashing for young children.
Play safely
Don’t kiss or snuggle hedgehogs, because this can spread Salmonella germs to your face and mouth and make you sick.
Don’t let hedgehogs roam freely in areas where food is prepared or stored, such as kitchens.
Clean habitats, toys, and supplies outside the house when possible. Avoid cleaning these items in the kitchen or any other location where food is prepared, served, or stored.
Welcome to Washington, D.C., Frank, and government PR.
On Nov. 20, the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention warned the American public of a multi-state outbreak of E. coli O157:H7 linked to romaine lettuce and advised against eating any romaine lettuce on the market at that time.
According to FDA Commissioner Scott Gottlieb, M.D. and FDA Deputy Commissioner Frank Yiannas, we have new results to report from this investigation tracing the source of the contamination to at least one specific farm. Based on these and other new findings, we’re updating our recommendations for the romaine lettuce industry and consumers. Today, we’re announcing that we’ve identified a positive sample result for the outbreak strain in the sediment of a local irrigation reservoir used by a single farm owned and operated by Adam Bros. Farms in Santa Barbara County.
The FDA will be sending investigators back to this farm for further sampling. It’s important to note that although this is an important piece of information, the finding on this farm doesn’t explain all illnesses and our traceback investigation will continue as we narrow down what commonalities this farm may have with other farms that are part of our investigation. While the analysis of the strain found in the people who got ill and the sediment in one of this farm’s water sources is a genetic match, our traceback work suggests that additional romaine lettuce shipped from other farms could also likely be implicated in the outbreak. Therefore, the water from the reservoir on this single farm doesn’t fully explain what the common source of the contamination. We are continuing to investigate what commonalities there could be from multiple farms in the region that could explain this finding in the water, and potentially the ultimate source of the outbreak.
As of Dec. 13, our investigation yielded records from five restaurants in four different states that have identified 11 different distributors, nine different growers, and eight different farms as potential sources of contaminated romaine lettuce. Currently, no single establishment is in common across the investigated supply chains. This indicates that although we have identified a positive sample from one farm to date, the outbreak may not be explained by a single farm, grower, harvester, or distributor.
At the same time, the U.S. Centers for Disease Control updated its warning to advise U.S. consumers to not eat and retailers and restaurants not serve or sell any romaine lettuce harvested from certain counties in the Central Coastal growing regions of northern and central California. If you do not know where the romaine is from, do not eat it.
Some romaine lettuce products are now labeled with a harvest location by region. Consumers, restaurants, and retailers should check bags or boxes of romaine lettuce for a label indicating where the lettuce was harvested.
Do not buy, serve, sell, or eat romaine lettuce from the following California counties: Monterey, San Benito, and Santa Barbara.
If the romaine lettuce is not labeled with a harvest growing region and county, do not buy, serve, sell, or eat it.
The Public Health Agency of Canada has identified ill people infected with the same DNA fingerprint of E. coliO157:H7 bacteria in Canada.
My mother used to make and lot of cakes and brownies with her groovy 1960s hand mixer and I always got to lick the beaters.
No more.
And it’s not just the raw eggs, it’s the raw flour.
In June, 2009, an outbreak of shiga-toxin producing E. coli (STEC, primarily O157:H7) in Nestle Toll House cookie dough sickened at least 77 people in 30 American states. Thirty-five people were hospitalized – from cookie dough.
The researchers could not conclusively implicate flour as the E. coli source, but it remains the prime suspect. They pointed out that a single purchase of contaminated flour might have been used to manufacture multiple lots and varieties of dough over a period of time as suggested by the use-by dates on the contaminated product.
The study authors concluded that “foods containing raw flour should be considered as possible vehicles of infection of future outbreaks of STEC.”
So it wasn’t much of a surprise when 63 people fell sick from the outbreak strain of E. coli O121 from Dec. 2015 to Sept. 2016 linked to raw General Mills flour.
There have been about a dozen other flour-related outbreaks. STEC means people – and kids – get quite sick.
Flour is a raw commodity, crops the flour is derived from could be exposed to anything, and testing is so much better than it used to be.
There are some brands of pasteurized flour out there, but people seem to have gotten used to flour as a cheap source of play-dough-like stuff for kids and something to throw at people.
The U.S. Centres for Disease Control says, nope.
This is not a Christmas conspiracy (although I prefer Solstice Season): it’s CDC providing information, like they are supposed to.
People can, and will, do what they want.
As Maggie Fox of NBC reports, “Do not taste or eat any raw dough or batter, whether for cookies, tortillas, pizza, biscuits, pancakes, or crafts made with raw flour, such as homemade play dough or holiday ornaments,” the CDC advises.
“Do not let children play with or eat raw dough, including dough for crafts.”
Handling food, including flour, requires care and hygiene.
“Keep raw foods such as flour or eggs separate from ready-to eat-foods. Because flour is a powder, it can spread easily,” the CDC notes. “Follow label directions to refrigerate products containing raw dough or eggs until they are cooked. Clean up thoroughly after handling flour, eggs, or raw dough.”
Turtles were inexpensive, popular, and low maintenance, with an array of groovy pre-molded plastic housing designs to choose from. Invariably they would escape, only to be found days later behind the couch along with the skeleton of the class bunny my younger sister brought home from kindergarten one weekend.
But eventually, replacement turtles became harder to come by. Reports started surfacing that people with pet turtles were getting sick. In 1975, the U.S. Food and Drug Administration (FDA) banned commercial distribution of turtles less than 4 inches in length, and it has been estimated that the FDA ban prevents some 100,000 cases of salmonellosis among children each year.
Maybe I picked up my turtle, rolled around on the carpet with it, pet it a bit, and then stuck my finger in my mouth. Maybe in my emotionally vacant adolescence I kissed my turtle. Who can remember?
The U.S. Centers for Disease Control reports today that in June 2017, PulseNet, the national molecular subtyping network for foodborne disease surveillance, identified 17 Salmonella Agbeni clinical isolates with indistinguishable XbaI enzyme pattern (outbreak strain) by pulsed-field gel electrophoresis. The same Salmonella Agbeni XbaI pattern was isolated from a turtle in 2015; in a 2016 investigation involving the same outbreak strain, 63% of patients reported contact with turtles (CDC, unpublished data, 2016). Despite prohibition of sale of small turtles (shell length less <4 inches) in the United States since 1975 (1), illness outbreaks associated with turtle contact continue to occur. Ill persons in previous Salmonella Poona and Salmonella Pomona outbreaks linked to turtles were geographically concentrated in the Southwest region of the United States (2,3). Turtle production is known to be higher in the Southeast region of the country (2). An outbreak investigation by CDC and health departments was initiated to identify the source of the 2017 illness outbreak.
A case was defined as isolation of Salmonella Agbeni with the outbreak strain from an ill patient during April–December 2017. State and local health officials interviewed patients to ascertain turtle exposure information, including details about the species of turtle and purchasing information. Purchase locations reported by patients were contacted for traceback information. Whole genome sequencing (WGS), using high quality single nucleotide polymorphism (hqSNP) analysis, was performed by CDC on clinical isolates from the 2017 outbreak, the 2016 illness cluster, and the turtle isolate from 2015 to characterize genetic relatedness.
Seventy-six cases were identified in 19 states in 2017; two thirds (67%) of patients resided in East Coast states (Connecticut, Delaware, Maryland, Massachusetts, New Jersey, New York, Pennsylvania, Rhode Island, and Virginia).* Patient ages ranged from <1–100 years (median = 21 years). Among 63 (83%) patients with information on hospitalization, 30 (48%) were hospitalized; no deaths were reported. Fifty-nine (78%) patients provided exposure information, including 23 (39%) who reported contact with turtles; among these, 14 (61%) specified small turtles. Among 12 patients who reported how the turtles were obtained, six purchased them from a street or roadside vendor, three purchased them from a retail store, two purchased them at festivals, and one reported receiving them as a gift. The traceback investigation did not identify a common turtle farm that supplied purchase locations. WGS hqSNP analysis indicated that the 2017 and 2016 clinical isolates and the 2015 turtle isolate were closely related, differing by 0–18 SNPs.
This salmonellosis outbreak was linked to contact with small turtles and was associated with a higher frequency of hospitalization (48%) than multistate foodborne pathogen outbreaks (27%) as well as recent Salmonella outbreaks linked to turtles (28%–33%) (2–4). The geographic distribution of patients differed from that of previous outbreaks, suggesting the need to better understand the breeding of turtles and distribution of turtle sales in the United States. WGS hqSNP analysis was used to link historic illnesses and turtle isolates to isolates from 2017 patients, supporting the hypothesis that turtles were the likely source of this outbreak. This outbreak indicates further need to educate consumers and retail store staff members regarding the ban on sale of small turtles and to educate consumers to prevent transmission of Salmonella from pets to humans.
Notes from the Field: An Outbreak of Salmonella Agbeni Infections Linked to Turtle Exposure — United States, 2017
MMWR 67(48);1350
Lia Koski, MPH1,2; Lauren Stevenson, MHS1,3; Jasmine Huffman1; Amy Robbins, MPH4; Julia Latash, MPH5,6; Enoma Omoregie, PhD5; Kelly Kline, MPH7; Megin Nichols, DVM1 (View author affiliations)
Gambino-Shirley K, Stevenson L, Concepción-Acevedo J, et al. Flea market finds and global exports: four multistate outbreaks of human Salmonellainfections linked to small turtles, United States—2015. Zoonoses Public Health 2018;65:560–8. CrossRefPubMed
Basler C, Bottichio L, Higa J, Prado B, Wong M, Bosch S. Multistate outbreak of human SalmonellaPoona infections associated with pet turtle exposure—United States, 2014. MMWR Morb Mortal Wkly Rep 2015;64:804. CrossRefPubMed
Longtime friend of the barfblog.com, Michéle Samarya-Timm, health educator at the Somerset County Department of Health (that’s in New Jersey, represent) writes:
Baking pumpkin pies with Aunt Kay’s secret recipe. Watching Miracle on 34th Street. Preparing the dining room with the good china. Diffusing political conversations at the dinner table.
Some traditions give a sense of warmth, connection, and continuity, and regularly define a family’s holiday. Unfortunately, there is now a need to add an additional tradition to the season – actively checking for foodborne outbreaks and recalls to prevent folks from getting sick.
Last week, on Tuesday, November 20th at 2pm, (two days before Thanksgiving), the CDC posted a media statement with advice to consumers, restaurants, and retailers:
“CDC is advising that U.S. consumers not eat any romaine lettuce, and retailers and restaurants not serve or sell any, until we learn more about the outbreak.”
The need to release such a notice, right before a major holiday is an unpropitious scenario. It was also very concerning in its specificity to consumers, retailers and restaurants:
“Wash and sanitize drawers or shelves in refrigerators where romaine was stored.”
Such an alert is most effective if it reaches the intended audiences. Folks at my holiday table did not hear about the outbreak. Neither did many local health departments.
Issuing media releases is one way for public health agencies to reach large groups of people. However, distracted by holiday preparations, travel, shopping, family, football and bad weather this advisory was only partially disseminated to the public. A person had to be following news outlets or social media to receive timely notice. I heard about the recall from the woman next to me while I was getting a haircut – not from the CDC or FDA, or any other federal or state agency.
It’s disturbing. The CDC could have sent this info directly to local health departments, or notify them that a news release was issued. This was not the first time as a local public health official that I received delayed – or no – official communication about a national foodborne issue.
Local public health professionals rely on communications systems established by federal and state oversight agencies. Most commonly, if a verified or suspect foodborne contamination or outbreak has occurred, the Centers for Disease Control and Prevention (CDC), the U.S. Department of Agriculture, or the U.S. Food and Drug Administration (FDA) will ascertain the appropriateness of information release. If this information is deemed credible, notification is forwarded individually or en masse to state departments of health. The states, in turn, push this information down to local regulators. Each step in the process contains elements that may delay the rapid dissemination of outbreak information. The ability and willingness of all stakeholders to quickly and readily share incident particulars with fellow responding agencies can enhance effectiveness and amplify response efforts.
Electronically sending this advisory directly to the nearly 3,000 local health departments in the US would provide the opportunity for hundreds of health inspectors, health educators, epidemiologists and other to reach the hospitals, food banks, schools, mom and pop establishments and local residents who may not have otherwise received the alert. This was a missed opportunity, and hopefully one that didn’t cause additional cases of illness.
As I’ve written before, coordinated communication strategies within and between public health agencies is less robust than it should be. As a result, state and local public health officials may hear about foodborne disease issues first from other sources, such as the media, word of mouth, public complaints, or the food industry.
We need to learn how to communicate better with each other. Local public health shouldn’t have to keep an eye on the news media, Twitter or Facebook for information pertinent to protecting the people in our jurisdictions. A multitude of electronic portals exist for purposes of interagency communication, CDC, FDA, and the public health system should collectively define how pertinent information – such as this romaine advisory – rapidly and routinely gets to the grass roots public health workforce. Continuously improving interagency coordination and communication is a goal that is fundamental to increasing the effectiveness of this nation’s food safety systems. I’m putting this out there, because I’m willing to help with the solution. That way, in future years, I can spend my holidays perfecting Aunt Kay’s pie recipe.
This holiday, I’m thankful for public health influencers and amplifiers – like barfblog.com – that act as outbreak aggregators, and push out info to local public health types like me.
Some background information and recommendations on this topic can be found in: Getting the message across: an analysis of foodborne outbreak communications between federal, state, and local health agencies https://calhoun.nps.edu/handle/10945/49379
The U.S. Centers for Disease Control reports on November 28, 2017, the manager of restaurant A in Tennessee reported receiving 18 complaints from patrons with gastrointestinal illness who had dined there on Thanksgiving Day, November 23, 2017. Tennessee Department of Health officials conducted an investigation to confirm the outbreak, assess exposures, and recommend measures to prevent continued spread.
On November 23, one patron vomited in a private dining room, and an employee immediately used disinfectant spray labeled as effective against norovirus* to clean the vomitus. After handwashing, the employee served family-style platters of food and cut pecan pie. For the November 23 Thanksgiving Day, restaurant A served 676 patrons a limited menu from 11 a.m. to 8 p.m. The manager provided contact information, seating times, and seating locations for 114 patrons with reservations. All patrons with contact information were telephoned, and a questionnaire was used to assess illness and exposures for anyone living in the household who ate at restaurant A on November 23. Stool specimens were requested from ill patrons. Among the 676 patrons, 137 (20%) were enrolled in a case-control study.
A probable case was defined as diarrhea (three or more loose stools in 24 hours) or vomiting within 72 hours of eating at restaurant A on November 23; probable cases with norovirus RNA detected in a stool specimen by real-time reverse transcription–polymerase-chain reaction (RT-PCR) were considered confirmed. On November 30, environmental swabs for norovirus testing were collected in the restaurant. Patient and environmental samples were tested by real-time RT-PCR and sequenced at the Tennessee State Public Health Laboratory.
Thirty-six (26%) case-patients (two confirmed and 34 probable) and 101 (74%) controls were enrolled in the case-control study. Illness onsets occurred during November 23–25, with 17 of 35 (49%) cases occurring on November 24. The mean incubation period was 31 hours (range = 2.5–54.5 hours), and the mean illness duration was 3 days (range = 0–6 days). Only one case-patient sought medical care. Diarrhea was reported by 33 (94%) case-patients, fatigue by 29 (83%), nausea and abdominal cramps by 28 (80%), vomiting by 24 (69%), and fever by six (17%).
Among menu items, only pecan pie was significantly associated with illness (odds ratio [OR] = 2.6; 95% confidence interval [CI] = 1.1–5.8); however, it was eaten by only 16 (47%) of 34 case-patients. The vomiting event occurred around noon; patrons seated during 11 a.m.–1 p.m. were significantly more likely to become ill than were patrons seated during other times (OR = 6.0; 95% CI = 2.6–15.3). No significant differences between dining locations (i.e., private dining room versus general seating) were identified (OR = 1.4; 95% CI = 0.4–4.3). Logistic regression was used to evaluate the effects of eating pecan pie, seating time, and seating location; only seating time during 11 a.m.–1 p.m. remained statistically significant (OR = 6.0; 95% CI = 2.2–16.5).
Stool specimens from two case-patients identified Norovirus GII.P16-GII.4 Sydney. Norovirus GII was identified in one environmental swab collected from the underside of a table leg adjacent to the vomitus.
A point-source norovirus outbreak occurred after an infected patron vomited in a restaurant. Transmission near the vomiting event likely occurred by aerosol or fomite. Norovirus spread throughout the restaurant could have occurred by aerosol, person-to-person, fomite, or foodborne routes. Inadequate employee handwashing likely facilitated foodborne transmission through servings of pecan pie.
In hospital settings, CDC and the Tennessee Department of Health recommend contact precautions (e.g., gloves and gowns) when personnel have contact with vomitus (1). Similarly, the Food and Drug Administration’s 2017 Food Code recommends restaurants have a written plan detailing when and how employees should use personal protective equipment for cleaning vomitus (2). Reinforcing the need for proper handwashing and performing thorough environmental cleaning with appropriate personal protective equipment in food service establishments can prevent or mitigate future outbreaks.
Acknowledgments
Teresa Vantrease, Jana Tolleson, Tiffany Rugless, Lee Wood, Anita Bryant-Winton, Heather Mendez, Jeannette Dill, Alan Pugh, Jason Pepper, Katie Nixon, Marcy McMillian, Jane Yackley; FoodCORE Interview Team; staff members from restaurant A.
Corresponding author: Julia Brennan, JBrennan@cdc.gov, 615-253-9971.
1Epidemic Intelligence Service, CDC; 2Division of Scientific Education and Professional Development, CDC; 3Communicable and Environmental Diseases and Emergency Preparedness, Tennessee Department of Health; 4Department of Health Policy, Vanderbilt University Medical Center, Nashville, Tennessee.
All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. William Schaffner reports personal fees from Pfizer, Merck, Dynavax, Seqirus, SutroVax, and Shionogi, outside the submitted work. No other potential conflicts of interest were disclosed.
* Active ingredients = n-Alkyl dimethyl benzyl ammonium chlorides and n-Alkyl dimethyl ethylbenzyl ammonium chlorides.
Twenty years later and whole genome sequencing is even further piecing together disparate outbreaks.
