Lesson in epidemiology (not): Wisconsin farmer says raw milk may not have made Durand football team ill

Posted on December 14, 2014 by Douglas Powell

Now that the Reed ranch has been named and shamed as the source of the raw milk linked to at least 38 illnesses of Campylobacter jejuni related to players and staff of the Durand High School football team, the owner is speaking out.

Diana Reed, whose farm provided the milk said, “Some people got sick who did not drink the milk,” she said Saturday.

State health officials also tested manure of the cows at the Reed ranch and concluded some of the cows contained the strain of Campylobacter that sickened the students.

On Friday, state health officials identified the Reed farm as the source of the milk following an open records inquiry by the Milwaukee Journal Sentinel.

But Reed said there could have been other sources of the bug.

“I discussed it with the epidemiologist in Madison. He gave me some statistics — 56 people ate chicken, 38 got sick; 43 people chose to drink milk and 33 got sick,” she said. “They interviewed everyone who was there.”

That leaves five people who did not drink milk, but who still had Campylobacter.

Epidemiology, just trying to do this jigsaw puzzle: Outbreak of E. coli O157:H7 associated with lettuce served at fast food chains in the Maritimes and Ontario, Canada, Dec 2012

Posted on October 16, 2014 by Douglas Powell

Background: Identification and control of multi-jurisdictional foodborne illness outbreaks can be complex because of their multidisciplinary nature and the number of investigative partners involved.

Objective: To describe the multi-jurisdictional outbreak response to an E. coli O157:H7 outbreak in Canada that highlights the importance of early notification and collaboration and the value of centralized interviewing.

Methods: Investigators from local, provincial and federal jurisdictions, using a national outbreak response protocol to clarify roles and responsibilities and facilitate collaboration, conducted a rapid investigation that included centralized re-interview of cases, descriptive methods, binomial probability, and traceback findings to identify the source of the outbreak.

Results: There were 31 laboratory confirmed cases identified in New Brunswick, Nova Scotia, and Ontario. Thirteen cases (42%) were hospitalized and one case (3%) developed hemolytic uremic syndrome; there were no deaths. Due to early notification a coordinated investigation was initiated before laboratory subtyping was available. Re-interview of cases identified 10 cases who had not initially reported exposure to the source of the outbreak. Less than one week after the Outbreak Investigation Coordinating Committee was formed, consumption of shredded lettuce from a fast food chain was identified as the likely source of the illnesses and the implicated importer/processor initiated a precautionary recall the same day.

Conclusion: This outbreak investigation highlights the importance of early notification, prompt re-interviewing and collaboration to rapidly identify the source of an outbreak.

Canada Communicable Disease Report CCDR

Tataryn J, Morton V, Cutler J, McDonald L, Whitfield Y, Billard B, Gad RR and Hexemer A

http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/14vol40/dr-rm40s-1/dr-rm40s-1-ecoli-eng.php

Use of social media to identify foodborne illness — Chicago, Illinois, 2013–2014

Posted on August 15, 2014 by Douglas Powell

An estimated 55 million to 105 million persons in the United States experience acute gastroenteritis caused by foodborne illness each year, resulting in costs of $2–$4 billion annually (1).

Many persons do not seek treatment, resulting in underreporting of the actual number of cases and cost of the illnesses (2). To prevent foodborne illness, local health departments nationwide license and inspect restaurants (3) and track and respond to foodborne illness complaints. New technology might allow health departments to engage with the public to improve foodborne illness surveillance (4). For example, the New York City Department of Health and Mental Hygiene examined restaurant reviews from an online review website to identify foodborne illness complaints (5). On March 23, 2013, the Chicago Department of Public Health (CDPH) and its civic partners launched FoodBorne Chicago (6), a website (https://www.foodbornechicago.orgExternal Web Site Icon) aimed at improving food safety in Chicago by identifying and responding to complaints on Twitter about possible foodborne illnesses. In 10 months, project staff members responded to 270 Twitter messages (tweets) and provided links to the FoodBorne Chicago complaint form.

A total of 193 complaints of possible foodborne illness were submitted through FoodBorne Chicago, and 133 restaurants in the city were inspected. Inspection reports indicated 21 (15.8%) restaurants failed inspection, and 33 (24.8%) passed with conditions indicating critical or serious violations. Eight tweets and 19 complaint forms to FoodBorne Chicago described seeking medical treatment. Collaboration between public health professionals and the public via social media might improve foodborne illness surveillance and response. CDPH is working to disseminate FoodBorne Chicago via freely available open source software

FoodBorne Chicago tracked Twitter messages using a supervised learning algorithm (7). The algorithm parsed tweets originating from Chicago that included “food poisoning” to identify specific instances of persons with complaints of foodborne illness. The geographic boundaries used by the algorithm also included some neighboring Chicago suburbs. However, follow-up inspections were conducted only at restaurant locations within the city limits. Tweets identified by the algorithm were reviewed by project staff members for indications of foodborne illness (e.g., stomach cramps, diarrhea, or vomiting) from food prepared outside the home. Project staff members provided feedback on whether each tweet fit the criteria, enabling the tweet identification algorithm to learn and become more effective over time.

For tweets meeting the criteria, project staff members used Twitter to reply. For example, Tweet: “Guess who’s got food poisoning? This girl!” Reply: “That doesn’t sound good. Help us prevent this and report where you ate here (link to Foodborne Chicago and a web form to report the illness).” The information in submitted forms went directly into the Chicago 311 system that handles all requests for nonemergency city services. Descriptive statistics were used to evaluate FoodBorne Chicago over its first 10 months of use and to compare the results of complaint-based health inspections of food establishments resulting from FoodBorne Chicago use with health inspections of food establishments based on complaints not submitted through FoodBorne Chicago. The comparisons did not include reinspections or routine inspections not based on a complaint.

During March 2013–January 2014, FoodBorne Chicago identified 2,241 “food poisoning” tweets originating from Chicago and neighboring suburbs. From these, project staff members identified 270 tweets describing specific instances of persons with complaints of foodborne illness. Eight of the 270 tweets (3.0%) mentioned a visit to a doctor or an emergency department. A total of 193 complaints of food poisoning were submitted through the FoodBorne Chicago web form. However, project staff members were not able to track how many of the 193 came from persons led to the form via Twitter and how many came from persons who visited the FoodBorne Chicago site on their own.

Of the 193 FoodBorne Chicago complaints, 19 (9.8%) persons indicated they sought medical care. The complaints identified 179 Chicago restaurant locations; at 133 (74.3%) locations, CDPH inspectors conducted unannounced health inspections. These 133 inspections amounted to 6.9% of the 1,941 health inspections of food establishments prompted by complaints during the study period. Of the 133 FoodBorne Chicago–prompted health inspections, 122 (91.7%) inspection reports identified at least one health violation, compared with 91.8% of inspection reports following complaints filed outside of FoodBorne Chicago during the same period.

Of the 133 FoodBorne Chicago–prompted health inspections 27 (20.3%) identified at least one critical violation, compared with 16.4% of the 1,808 inspections not prompted by FoodBorne Chicago. Critical violations indicate an “immediate health hazard” resulting in a high risk for foodborne illness. Critical violations must be fixed while the inspector is present or the restaurant fails inspection, has its license suspended, and is closed.* Twenty-nine restaurants (21.8%) reported via FoodBorne Chicago had at least one serious violation compared with 27.8% of restaurants not reported via FoodBorne Chicago. Serious violations indicate a “potential health hazard” that must be corrected within a timeframe determined by the health inspector, typically 5 days. If the serious violation is not fixed on re-inspection, the license is suspended, and the business is closed. Overall, at least one critical or serious violation was found in 37.6% of inspections prompted by FoodBorne Chicago and 37.2% of inspections from other complaints during the same period.

Some differences were noted in the distribution of specific violations between FoodBorne Chicago inspections and other complaint inspections. For example, 13.5% of FoodBorne Chicago inspections resulted in (critical) violation 3 (i.e., food not stored at appropriate temperatures), compared with 8.2% of other complaint inspections (Table). In addition, 14.3% of other complaint inspections reported (serious) violation 18 (i.e., food not protected from contamination), compared with 6% of FoodBorne inspections.

A total of 21 (15.8%) of the 133 restaurants reported through FoodBorne Chicago failed inspection and were closed; an additional 33 restaurants (24.8%) passed with conditions, indicating that serious or critical violations were identified and corrected during inspection or within a specified timeframe. Of the inspected restaurants with complaints not reported through FoodBorne Chicago, 25.8% failed and 14.2% passed with conditions. During the study period, among all restaurants inspected, FoodBorne Chicago–prompted inspections accounted for 4.3% of failed inspections and 11.4% of pass with conditions inspections.

Centers for Disease Control and Prevention

Jenine K. Harris, PhD, Raed Mansour, MS, Bechara Choucair, MD, Joe Olson, Cory Nissen, MS, Jay Bhatt, DO

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6332a1.htm?s_cid=mm6332a1_x

Smartphones lead to smarter outbreak investigations: Clostridium perfringens, London, March 2013

Posted on May 15, 2014 by Douglas Powell

On 22 March 2013, 150 of 1,255 students (13–17 years) and staff at a school in London reported gastrointestinal symptoms; onset peaked 8 to 12 hours after a lunch served in the school on 21 March. We performed a retrospective cohort study of all students and staff. We defined cases as school attenders on 20 and 21 March with onset of gastrointestinal symptoms between 20 and 23 March.

We tested food, environmental and stool samples of cases for common pathogens and bacterial toxins. We administered an online questionnaire via email, encouraging the use of smartphones to respond, to measure risk of illness for food items eaten at school on 20 and 21 March. Survey response was 45%. Adjusted risk ratios were generated in a multivariable analysis. Those who ate chicken balti on 21 March were 19.3 times more likely to become ill (95% confidence interval: 7.3–50.9). Clostridium perfringens was detected in all 19 stool samples collected. Within eight school hours of its launch, 412 of 561 (73%) responders had completed the survey. Hygienic standards in the kitchen were satisfactory. The investigation was done rapidly due to smartphone technology and we recommend considering this technology in future outbreaks.

Euro Surveill. 2014;19(19)

Simone B, Atchison C, Ruiz B, Greenop P, Dave J, Ready D, Maguire H, Walsh B, Anderson S.

Food Safety Talk episode 52: A Keene epidemiologist

Posted on December 21, 2013 by Ben Chapman

Food Safety Talk, a bi-weekly podcast for food safety nerds, by food safety nerds. The podcast is hosted by Ben Chapman and barfblog contributor Don Schaffner, Extension Specialist in Food Science and Professor at Rutgers University. Every two weeks or so, Ben and Don get together virtually and talk for about an hour. They talk about what’s on their minds or in the news regarding food safety, and popular culture. They strive to be relevant, funny and informative — sometimes they succeed. You can download the audio recordings right from the website, or subscribe using iTunes.

The guys started the show dreaming about a Red Mac Pro. They then turned to the passing of Bill Keene. Bill has been mentioned in various FST episodes and was a well respected epidemiologist as seen in the articles by the Oregonian and Doug Powell. The guys then turned to their beverages, Coffee Club, Napoleon Dynamite, Homeland, and Car Talk. Ben shared his preference for Aussie Rule football and Arcade Fire’s album Reflektor. The conversation then turned to Don’s limited iPhone music library, Privateering and Dire Straights, which reminded Ben of Money for Nothing and WWE Wrestling (not WWF Wrestling). To finish they talked about Christmas music, Bad Religion’s Christmas Songs, Coulton and Roderick’s One Christmas at a Time and Horrible Christmas songs.

Ben confused IAFP’s History with Bug Trivia and shared Julian Cox’s information about the 1960’s, and this evolved into a broader discussion about the IAFP and its membership.

The discussion then turned back to Bill Keene and some of the outbreaks he had been involved in. This included a Salmonella Panama outbreak (not to be confused with Van Halen’s Panama), which was the first outbreak that was solved through the innovative use of supermarket loyalty cards and that Bill and others were sued for (the lawsuit was eventually dropped.. The guys then discussed outbreak investigation in some detail and that public health officials are damned if they do and damned if they don’t name commodities and suppliers. There is of course always a risk of getting the epidemiology wrong, as was the case with Salmonella Saintpaul in peppers. Finally, Bill’s investigation of a Norovirus outbreak reminded Ben of a recent Norovirus outbreak in Las Vegas.

Then Ben commented on an exchange with Chris Gunter, who was presenting on traceability for small producers at the 2013 Strawberry Expo. Chris’ presentation is based on the investigation of an E. coli O157 outbreak related to strawberries, in which Bill Keene played a part.

In the after dark, the guys reflected on mortality and that we should all Enjoy Every Sandwich. And because they love him, Rob Ford got a mention again and again.

Deadly outbreaks: How medical detectives save lives threatened by killer pandemics, exotic viruses, and drug-resistant parasites

Posted on October 16, 2013 by Douglas Powell

Atif Kukaswadia writes in this review on Public Health Perspectives blog: Anyone who follows my writing knows that I’m a big proponent of using stories to talk about science. We’ve discussed how you can use science fiction teach science, zombies to talk about disease outbreaks, and my TEDx talk discussed using principles of storytelling in how we discuss science. So when I was asked to review (see disclaimer below) Dr Alexandra Levitt’s new book “Deadly Outbreaks: How Medical Detectives Save Lives Threatened by Killer Pandemics, Exotic Viruses and Drug-Resistant Parasites,” I jumped on the opportunity.

The CDC has a program known as the Epidemiologic Intelligence Services, where individuals trained in fields such as epidemiology, medicine, statistics and veterinary sciences come together to identify causes of diseases. For an overview of the EIS, check out this review of “Inside the Outbreaks” by Travis Saunders over at Obesity Panacea. The EIS was set up Alexander Langmuir, who has been profiled on the blog, and their work has been instrumental in learning about, and thus containing, disease outbreaks all over the world. Dr Levitt is well positioned to speak on these issues, having worked at the CDC since 1995, although it should be noted that this was written in her free time, not as part of her position at the CDC.

The book is comprised of 7 distinct chapters, each one covering a unique disease outbreak. In an almost “House-ian” style, the EIS agent will hear about an outbreak, go into an area, and then have to uncover what it is that is causing people to get sick, often with very little information to go on. I’m going to keep the details deliberately vague, as part of the joy of reading the book is guessing what is causing the outbreak, and following the train of thought of the investigators.

Another thing I really enjoyed about the book was how Dr Levitt deals with all important stakeholders, and talks about their history. One chapter deals with a Native American population that has undergone a disease outbreak, and does a great job explaining the history of these people. This is very pertinent information, as the problems of going into this community are a direct result of how these communities have been treated historically, and everything from the equipment you bring in, to the name of the disease, has to be cleared by elders and community leaders. The history of a group is something public health practitioners need to be aware of and sensitive to in order to work with these people to identify causes of disease, and this was illustrated well in this book.

Finally, at a more stylistic level, a conscious decision the author makes is to provide context for the characters. For example, in Chapter 1 the “protagonist” is eagerly anticipating her wedding, and at one point goes for dinner and discusses this with a colleague while talking about the case at hand. In a later chapter, the author describes Dr Stacy Holzbauer, a veterinarian, as someone whose “plan was to become a large-animal veterianian, marry a cowboy, live on a ranch on the Great Plains, and raise cowboys,” a vivid and charming description. While she did become a veterinarian, she then pursued a MPH and now does brilliant public health work. This makes the characters that much more fleshed out and human, rather than being 2-dimensional and alien, a welcome respite from the socially awkward, comically inept, and often evil, scientist of television and film. At points I found this transition jarring, but it adds to the overall feel of the book, and I think helps the book connect with the general public.

And the general public, especially those with an interest in public health, is the target audience. I would recommend this book to those interested in learning more about public health, both from an infectious disease standpoint, as well as from a practical, i.e. how do we actually investigate disease outbreaks, standpoint. It’s written for a lay audience, and avoids jargon and delving too far into statistics or biology, which makes it easy and straightforward to follow. If you’re considering pursuing an MPH and want to do “shoe leather epidemiology,” it’s a must read.

6 sickened; Salmonella-contaminated blueberries from Georgia in 2010 tracked down by Minn. health types using GTINs and shopper cards

Posted on May 8, 2013 by Douglas Powell

Abstract:

In August 2010, the Minnesota Department of Agriculture and Minnesota Department of Health investigated an outbreak of six cases of Salmonella Newport infection occurring in northwestern Minnesota, which identified fresh blueberries as the cause. Initially, traditional traceback methods involving the review of invoices and bills of lading were used to attempt to identify the source of the outbreak. When these methods failed, novel traceback methods were used. Specifically, supplier-specific 12-digit Global Trade Item Numbers (GTINs) and shopper-card information were used to identify a single blueberry grower linked to cases, corroborating the results of a case-control study in which consuming fresh blueberries was statistically associated with illness (5 of 5 cases versus 8 of 19 controls, matched odds ratio [MOR] undefined, P = 0.02). Consuming fresh blueberries from retailer A was also statistically associated with illness (3 of 3 cases versus 3 of 18 controls, MOR undefined, P = 0.03). Based on initially incomplete evidence in this investigation, the invoices pointed to wholesaler A and grower A, based on first-in-first-out product rotation. However, when point-of-sale data were analyzed and linked to shopper-card information, a common GTIN was identified. This information led to an on-site record evaluation at retailer A, and the discovery of additional records at this location documented the supply chain from grower B to wholesaler C to retailer A, shifting the focus of the investigation from grower A to grower B. This investigation demonstrates the emerging concepts of Critical Tracking Events (CTEs) and Key Data Elements (KDE) related to food product tracing. The use of these shopper-cased data and the event data that were queried by investigators demonstrates the potential utility of consciously designed CTEs and KDEs at critical points in the supply chain to better facilitate product tracing.

Use of Global Trade Item Numbers in the investigation of a Salmonella newport outbreak associated with blueberries in Minnesota, 2010

Journal of Food Protection®, Number 5, May 2013, pp. 744-918 , pp. 762-769(8)

Miller, Benjamin D.; Rigdon, Carrie E.; Robinson, Trisha J.; Hedberg, Craig; Smith, Kirk E.

http://www.ingentaconnect.com/content/iafp/jfp/2013/00000076/00000005/art00004

Epidemiology witches don’t get enough credit

Posted on January 16, 2013 by Ben Chapman

Foodborne illness outbreaks are messy. Not just for the unlucky individuals feeling the consequences in the bathroom, but for investigators and business owners. An outbreak is rarely solved with a smoking gun (like a pile of deer poop). Often the source is determined by the Nate-Silveresque witches in the epidemiology department. I’m in awe of the folks who take the available data well after an incident happens and utilize statistics to uncover clues to a vomit or diarrhea mystery.

Looking at the predictable responses that often pop up from business operators during an outbreak investigation, I’m not sure a lot of other folks outside the food safety world share this awe. All they seem to want to see are test results.

Count Ming Chang of Ming’s Sushi and Dimsum in the ever-so-exciting home of the Petes, Peterborough, Ontario (that’s in Canada) as someone who needs to see a Salmonella-positive sample to be convinced.

Lance Anderson of My Kawartha quotes Chang as saying, “They found nothing” (meaning no positive samples).

Ming Chang, owner of the Lansdowne Street West restaurant, says the local health unit gave the green light to reopen morning after all salmonella testing turned up negative results.

According to the health unit, in December 18 salmonella cases were identified from patrons who had eaten at the restaurant.

Mr. Chang isn’t convinced to outbreak started at his restaurant considering all tests the health unit conducted came back negative.”It could have come from anywhere,” he adds (yeah, but the epidemiological data the health unit has seems to point to Ming’s).

Mr. Chang says the health unit shut him down after some people got sick even though salmonella wasn’t found in the business. “They went on people’s testimonies. Basically I was found guilty before being proven guilty,” says Mr. Chang.”We’ve passed all our inspections here for the past two years.”

Maybe epidemiology’s image needs a makeover. If only it was called Kardashiology, maybe folks would pay attention.

Did bad berliners sicken over 100 in South Australia with Salmonella

Posted on November 16, 2012 by Douglas Powell

Beginning in Jan. 2011, 107 people in South Australia were sickened with Salmonella linked to custard-filled berliners.

Yesterday, the State Government told the Supreme Court it spoke truth when it blamed iconic baker Vili Milisits as the source.

Mr Milisits has asserted public health director Dr Kevin Buckett defamed him in two press conferences and one radio interview by blaming the berliners for food poisoning that affected more than 100 people.

John Whitington, acting for Mr Milisits, was quoted by the Herald Sun as saying, “The Government says the Department of Health conducted investigations, in late January, as a result of increased incidence of reported Salmonella. It says a statistically-significant proportion of people were interviewed.

“It says that, based on that analysis, a person infected with the salmonella bacteria was 38 times more likely to have eaten a custard-filled berliner.”

He asked Judge Brian Withers to order the Government to release that material to Mr Milisits’ legal team, along with the names of the people interviewed.

Judge Withers has reserved his decision.

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