Tag Archives: Surveillance

Surveillance, advance warning not enough; 172 sickened; a long-lasting outbreak of S. Typhimurium U323 associated with several pork products, Denmark, 2010

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On March 23, 2010, the national food surveillance system in Denmark reported a steady occurrence of positive isolates of S. Typhimurium, of unknown phage type and resistant to ampicillin, streptomycin and sulphamethoxazole, in samples from mainly pork meat and products.

Researchers from Denmark and Sweden report in Epidemiology and Infection that several isolates originated from a specific pig slaughterhouse A or a closely associated cutting plant. At this point, although no human cases had yet been identified, an investigation was initiated with the focus on food contamination. On 20 April, a total of 14 human cases with the outbreak type had been confirmed.

A case-control study was undertaken to confirm an association between illness in a subgroup of patients and consumption of teewurst or tea sausage, a spreadable sausage made from fresh salted and smoked pork and beef which is fermented but not heat-treated. The producer of the teewurst had received pork from slaughterhouse A during the period that the outbreak strain had been isolated.

Herds delivering pigs to slaughterhouse A were identified by a unique herd identification number given to all animal herds in Denmark.

From March 2010 and onwards, the outbreak strain was identified in a total of 113 samples; four environmental samples from slaughterhouse A and 109 meat
samples, mainly pork, of which 96 were sampled directly at slaughterhouse A or could be traced back there. Positive meat types included mainly minced pork, pork belly, pork loin and loin back ribs.

Investigation of slaughterhouse A showed positive discovery of the outbreak strain in swabs from equipment and meat samples, even after closing down production for thorough cleaning and disinfection. It was concluded that the establishment was most likely contaminated. Repeated cleaning and disinfection was performed and alterations in equipment and procedures were implemented, From the beginning of July, no further positive samples of the outbreak strain were found at slaughterhouse A.

On 8 July, a press statement was issued jointly by the DVFA and SSI, notifying the public about the salmonellosis outbreak and the link to consumption of pork meat from slaughterhouse A. In addition to describing the outbreak investigation and the action taken to control the outbreak, the statement also contained detailed guidelines on how to prevent infection with Salmonella.

A total of 172 cases of S. Typhimurium U323 were reported between March and September 2010 in Denmark demonstrating how a combination of typing Salmonella isolates from farm-to-fork and from the human population can provide early warning of a salmonellosis outbreak. It also highlights the importance of national Salmonella surveillance which allowed identification of the slaughterhouse contamination and provided the COMG with valuable information to initiate investigative measures. In spite of the existence of these systems, tracing pork meat that has entered the production chain still poses a significant challenge. If feasible, adoption of a standardized automated system across the EU, with detailed product and distribution information, for tracing products might prove worthwhile.

Currently, this is not possible in the EU and such systems are only as good as the data provided by the operators. At present, by the time enough evidence has been gathered to issue a product recall, products with a short shelf-life (such as fresh meat) are most likely to have been consumed.

In this outbreak, early warnings from the Salmonella surveillance system were not sufficient to prevent the outbreak from lasting almost 7 months.

State-of-the-art surveillance, typing, epidemiology and food traceback allowed us to firmly establish the source of the outbreak and, in essence, solve it almost before it became evident; however, legislative measures and some delays in traceback did not allow for sufficient control, resulting in one of the longest lasting Salmonella outbreaks in Denmark.

Snappy title alert: ‘C-Enter Net 2010 short report’ (pooping causes in Canada)

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The latest report from Canada’s National Integrated Enteric Pathogen Surveillance System has hit the Intertubes. Think of it as FoodNet, 15 years late.

Only bureaucrats could have written this.

In 2010, campylobacteriosis, salmonellosis and giardiasis (beaver fever? Oh, it’s Canada) were the most common enteric diseases in C-EnterNet’s sentinel sites, with rates of 29.5/100,000, 26.0/100,000 and 14.2/100,000, respectively. Overall, the number of endemic, travel- and outbreak-related cases reported in SS1 in 2010 were higher than that reported in 2009. In SS1, the incidence rate of campylobacteriosis, especially travel-associated infections, was higher in 2010 than 2009. The incidence rate of endemic salmonellosis has increased in both sentinel sites over the last couple of years, with SS2 steadily increasing since 2006.

Travel continues to be an important factor in the burden of enteric disease. In 2010, 30% and 23% of all cases of enteric disease were associated with travel outside of Canada, in SS1 and SS2 respectively. In both sentinel sites, the travel-related proportion of cases, compared with endemic cases, was highest for cyclosporiasis (100% in both SS1 and SS2), shigellosis (83% (SS1) and 33% (SS2)) and cryptosporidosis (43% (SS1) and 60% (SS2)).

C-EnterNet is an integrated enteric pathogen surveillance system based on a sentinel site surveillance model collecting information on both cases of infectious gastrointestinal illness and sources of exposure within defined communities. C-EnterNet’s primary objectives are to detect changes in trends in human enteric disease and levels of pathogen exposure from food, animal and water sources in a defined population; and to strengthen source attribution efforts in Canada by determining statistically significant risk factors for enteric illness.

In 2010, C-EnterNet implemented a second sentinel site in part of the Fraser Valley in the lower mainland of British Columbia, in partnership with the Fraser Health Authority (FHA). The communities of Burnaby, Abbotsford and Chilliwack comprise the sentinel site within the Fraser Health Region. In this region, active surveillance of enteric pathogens is performed in the retail sampling of bagged leafy greens, and enhanced human disease surveillance is performed in collaboration with FHA and the BCCDC Public Health Microbiology and Reference Laboratory. In the first sentinel site, C-EnterNet continues its strong partnership with the Region of Waterloo Public Health within the Regional Municipality of Waterloo, Ontario and the Ontario Agency for Health Protection and Promotion’s Toronto Public Health Laboratory where enhanced surveillance of human cases of enteric disease in the community is performed. In parallel, active surveillance of enteric pathogens is performed in water, food and on farms.

The purpose of this report is to present the preliminary findings from the 2010 surveillance year in both sentinel sites. Note that C-EnterNet data need to be considered in the context of two sentinel sites, thus major conclusions cannot yet be extrapolated nationally.1 This report will be followed by the Long Report, which will include more extensive analyses of temporal trends and subtyping information for an integrated perspective on enteric disease from exposure to illness for 2010.

For further information about the C-EnterNet program or sampling methodologies, please refer to our website (http://www.phac-aspc.gc.ca/c-enternet/index-eng.php).

US outbreaks linked to imported foods increasing, so are imports

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Foodborne disease outbreaks caused by imported food appeared to rise in 2009 and 2010, and nearly half of the outbreaks implicated foods imported from areas which previously had not been associated with outbreaks, according to research from the U.S. Centers for Disease Control and Prevention, presented today at the International Conference on Emerging Infectious Diseases in Atlanta.

“It’s too early to say if the recent numbers represent a trend, but CDC officials are analyzing information from 2011 and will continue to monitor for these outbreaks in the future,” said Hannah Gould, Ph.D., an epidemiologist in CDC’s Division of Foodborne, Waterborne and Environmental Diseases and the lead author.

CDC experts reviewed outbreaks reported to CDC’s Foodborne Disease Outbreak Surveillance System from 2005-2010 for implicated foods that were imported into the United States. During that five-year period, 39 outbreaks and 2,348 illnesses were linked to imported food from 15 countries. Of those outbreaks, nearly half (17) occurred in 2009 and 2010. Overall, fish (17 outbreaks) were the most common source of implicated imported foodborne disease outbreaks, followed by spices (six outbreaks including five from fresh or dried peppers). Nearly 45 percent of the imported foods causing outbreaks came from Asia.

“As our food supply becomes more global, people are eating foods from all over the world, potentially exposing them to germs from all corners of the world, too,” Gould said. “We saw an increased number of outbreaks due to imported foods during recent years, and more types of foods from more countries causing outbreaks.”

According to a report by the Department of Agriculture’s Economic Research Service (ERS), U.S. food imports grew from $41 billion in 1998 to $78 billion in 2007. Much of that growth has occurred in fruit and vegetables, seafood and processed food products. The report estimated that as much as 85 percent of the seafood eaten in the United States is imported, and depending on the time of the year, up to 60 percent of fresh produce is imported. ERS also estimated that about 16 percent of all food eaten in the United States is imported. The types of food causing the outbreaks in this analysis aligned closely with the types of food that were most commonly imported.

Food safety in Europe: salmonella down, campylobacter up, shiga toxin producing E. coli also up

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The European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC) have published their annual report on zoonoses and foodborne outbreaks in the European Union for 2010. The report shows that Salmonella cases in humans fell by almost 9% in 2010, marking a decrease for the sixth consecutive year. Salmonella prevalence in poultry is also clearly declining at the EU level.

Campylobacteriosis remains the most reported zoonotic infection in humans since 2005 and the number of cases has been increasing over the last five years. This report supports the European Commission and EU Member States in their consideration of possible measures to protect consumers from risks related to zoonoses.

According to the report, the likely main reasons for the decrease in human salmonellosis cases are the successful EU Salmonella control programmes for reducing the prevalence of the bacteria in poultry populations, particularly in laying hens[

The report also gives an overview of other food-borne diseases. Human cases of Shiga toxin/verotoxin -producing Escherichia coli (STEC/VTEC) have been increasing since 2008 and amounted to 4,000 reported cases in 2010.

Shiga toxin-producing E. coli in feces and lymphatic tissue of free-ranging deer in Germany

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I sorta cringe, or maybe sigh, every time someone faithfully repeats the dogma that factory-farmed cattle are the source of E. coli O157:H7 and other shiga-toxin producing E. coli (STEC).

All ruminants carry STEC naturally, and there are well-documented and tragic outbreaks involving deer, goats, sheep, elk and others.

German researchers report on the occurrence of STEC in deer in Germany in the current issue of Epidemiology and Infection.

Deer poop has been directly or indirectly linked to several outbreaks:

• 1 dead and 14 sickened from E. coli O157:H7 from deer feces contaminating strawberries in Oregon in Aug. 2011;

• deer feces were a possible source of E. coli O157 in Oregon hazelnuts that sickened 8 in March 2011;

• 29 Minnesota high school students sickened with E. coli O103 and E. coli O145 after butchering and processing deer into venison in 2010;

• deer meat was involved in at least two recognized E. coli outbreaks; and,

• an E. coli O157:H7 outbreak in Oct. 1996 that killed a 16-month-old and sickened 76 others who drank juice which contained unpasteurized apple cider that was probably contaminated with deer feces.

In the current study, the Germans studied the virulence genes eae, e-hlyA and saa, thestx subtypes, pulsed-field gel electrophoresis (PFGE) patterns and serovars. In total, 120 samples of 60 animals were screened by real-time polymerase chain reaction (PCR). The PCR results showed a high detection rate of stx genes (83%). Mainly faecal samples, but also some lymphatic tissue samples, tested stx-positive. All isolates carried stx2, were eae-negative and carried e-hlyA in 38% and saa in 9% of samples. Serovars (O88:[H8], O174:[H8], O146:H28) associated with human diseases were also identified. In some animals, isolates from lymphatic tissue and faecal samples showed undistinguishable PFGE patterns. The examined deer were shown to be relevant reservoirs of STEC with subtype stx2b predominating.

The complete paper is available at http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8501556.

Webidemiology: disease sleuths surf for outbreaks online

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 Most folks who wake up feeling crummy will sit down with a computer or smartphone before they sit down with a doctor.

They might search the Web for remedies or tweet about their symptoms. And that’s why scientists who track disease are turning to the Internet for early warning signs of epidemics.

Philip Polgreen, an epidemiologist at the University of Iowa, told NPR’s Adam Cole, "Surveillance is one of the cornerstones of public health. It all depends on having not only accurate data, but timely data."

The current system requires the Centers for Disease Control and Prevention to compile reports about from physicians and labs all over the country — and that can take a while. There’s typically a week-long delay between an outbreak and the release of an official report.

To get an early read on things, epidemiologists look for the first clues of illness — a rise in thermometer sales or increased chatter on hospital phone lines. Now, they’re tapping into the Internet.

A team of researchers at Johns Hopkins wanted to see if Google’s estimates would prove accurate and useful in the everyday operation of a hospital.

They compared Google searches originating in Baltimore to the number of patients who showed up with flu-like symptoms at a local emergency room.

"It seems like a stretch, but what we found — amazingly — is that there’s a really high correlation between these searches in the community and what we’re seeing in hospitals," says Richard Rothman, the study’s co-author.

Online disease surveillance — or "Webidemiology" — is a cool new tool, and researchers are eagerly testing it out and double-checking the data they collect. But it won’t be used by itself to make important public health decisions anytime soon.

"The Internet is just one additional stream of information," Polgreen says. "It’s certainly not going to replace traditional forms of surveillance."

While the Internet may not be a perfect predictive tool, researchers and public health officials agree that it is great for one thing: communication.

Social networking allows officials to easily reach the public and enter into a conversation. Tweets, searches and Facebook posts can give officials a sense of public reaction to vaccines, or their attitude towards an epidemic.

"It’s a quick and easy barometer for public anxiety," Polgreen says.
And in a public health emergency, that can be just as useful as cold, hard numbers about cases.

Surveillance of acute infectious gastroenteritis (1992–2009) and foodborne disease outbreaks (1996–2009) in Italy

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From this week’s Eurosurveillance, Mughini-Gras et al. describe trends in the occurrence of acute infectious gastroenteritis (1992 to 2009) and food-borne disease outbreaks (1996 to 2009) in Italy.

In 2002, the Piedmont region implemented a surveillance system for early detection and control of foodborne disease outbreaks; in 2004, the Lombardy region implemented a system for surveillance of all notifiable human infectious diseases. Both systems are Internet based.

We compared the regional figures with the national mean using official notification data provided by the National Infectious Diseases Notification System (SIMI) and the National Institute of Statistics (ISTAT), in order to provide additional information about the epidemiology of these diseases in Italy. When compared with the national mean, data from the two regional systems showed a significant increase in notification rates of non-typhoid salmonellosis and infectious diarrhea other than non-typhoid salmonellosis, but for foodborne disease outbreaks, the increase was not statistically significant.

Although the two regional systems have different objectives and structures, they showed improved sensitivity regarding notification of cases of acute infectious gastroenteritis and, to a lesser extent, food-borne disease outbreaks, and thus provide a more complete picture of the epidemiology of these diseases in Italy.

Peer-review has a purpose: Canadian food safety study long on rhetoric, short on data

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A new report says Canadians suffer more foodborne illness than Americans, that most of it happens with restaurant meals, and that consumers are sorta dumb too.

Unfortunately, the report relies heavily on other reports that are not peer-reviewed, assumptions, and suffers from highly selective referencing to make a point – and I have no idea what that point is.

The report, Improving Food Safety in Canada: Toward a More Risk Responsive System, released by the Conference Board of Canada to coincide with their food safety conference and upstaged by Galen Weston Jr.’s comments that farmer’s markets were going to kill someone, says half or more of all cases of foodborne illnesses in Canada are picked up in restaurants or from other food service providers.

Daniel Munro, Principal Research Associate, said, “It is commonly assumed that farms and food processing companies hold the most responsibility for ensuring safe food, and their role is critical. But most foodborne illnesses are associated with the preparation and storage practices of restaurants, food service operations, and consumers themselves.”

I’m not sure who makes that assumption. It is estimated there are 6.8 million cases of food-borne illness annually in Canada.

Part of the problem can be traced to restaurant inspection systems that are seen as too sporadic to have an impact on restaurants’ day-to-day food safety practices.

Garth Whyte, president and CEO of the Canadian Restaurant and Foodservices Association dismissed the report describing it as "shockingly short on facts."

"This study did not even bother contacting us about what we are doing, and if they had, they would know that there are three government recognized food safety training programs that train tens of thousands food handlers per year," Whyte said.

Except training alone doesn’t do much for food safety behavior.

The report provides a number of recommendations to improve Canada’s food safety system including providing restaurants and other food service providers with timely information and advice on how they can minimize food safety risks.

We call them infosheets.

It also urges governments to build on current consumer awareness initiatives by engaging consumers directly in discussions about food safety in their households.

The report offers no advice on how to do that.

Dangerous E. coli infections up 19% in Scotland; declines in salmonella, campylobacter

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Health Protection Scotland (HPS) said it had recorded 253 positive cases of E. coli during 2011, up from 212 the previous year.

The agency blamed the increase on a UK-wide outbreak believed to have originated from contaminated vegetables. The outbreak, between December 2010 and July 2011, saw 250 cases of E. coli infection throughout England, Wales and Scotland and 74 victims treated in hospital.

A subsequent investigation pointed to a possible link between leeks and potatoes bought loose and prepared in the home.

However, the HPS report also noted that the apparent spike in E. coli between 2010 and 2011 was partly due to the unusually low rate of E. coli infection in 2010.

The report also noted decreases in salmonella and campylobacter.
In 2011, HPS received reports of 736 cases of salmonella infection – a decrease of almost 22% on the 941 reported in 2010.

Cases of campylobacter were also down 3.6% to 6366 last year, although the figure remains "one of the highest on record."

Norovirus, salmonella cause bulk of known US foodborne illness; meat, produce primary vehicles

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The US. Centers for Disease Control reported today that in 2008, 1,034 foodborne disease outbreaks were reported, which resulted in 23,152 cases of illness, 1,276 hospitalizations, and 22 deaths. Among the 479 outbreaks with a laboratory-confirmed single etiologic agent reported, norovirus was the most common, accounting for 49% of outbreaks and 46% of illnesses. Salmonella was the second most common, accounting for 23% of outbreaks and 31% of illnesses. Among the 218 outbreaks attributed to a food vehicle with ingredients from only one of 17 defined food commodities, the top commodities to which outbreaks were attributed were poultry (15%), beef (14%), and finfish (14%), whereas the top commodities to which outbreak-related illnesses were attributed were fruits and nuts (24%), vine-stalk vegetables (23%), and beef (13%).

Since 1992, CDC has defined a foodborne disease outbreak as the occurrence of two or more similar illnesses resulting from ingestion of a common food. State, local, and territorial health department officials use a standard, Internet-based form to voluntarily submit reports of foodborne outbreaks to CDC. An online toolkit of clinical and laboratory information is available to support investigation and reporting of outbreaks.

The number (1,034) of outbreaks was 10% lower than the annual average reported (1,151) for 2003–2007, and the number of outbreak-related illnesses was 5% lower (23,152 versus 24,400).

Of the total number of outbreak-related foodborne illnesses, 1,276 (6%) resulted in hospitalization. Salmonella was the most common cause of outbreak-related hospitalizations, causing 62% of hospitalizations reported, followed by Shiga toxin–producing Escherichia coli (STEC) (17%) and norovirus (7%). Outbreaks caused by Clostridium botulinum resulted in the highest proportion of persons hospitalized (90%), followed by Listeria outbreaks (76%). Among the 22 deaths associated with foodborne disease outbreaks in 2008, 20 were attributed to bacterial etiologies (13 Salmonella, three Listeria monocytogenes, three STEC [two O157, one O111], one Staphylococcus), one to norovirus, and one to a mycotoxin.

Among the 868 outbreaks with a known single setting where food was consumed, 52% resulted from food consumed in a restaurant or deli, 15% in a private home, and the remainder in other locations.

Ref: Surveillance for foodborne disease outbreaks — United States, 2008. Morbidity and Mortality Weekly Report, September 9, 2011 / 60(35); 1197-1202.