It’s not just bacteria and viruses; parasites in leafy greens

On July 7, 1997, a company physician reported to the Alexandria Department of Health (ADOH) that most of the employees who attended a corporate luncheon on June 26 at the company’s branch in Fairfax, Virginia, had developed gastrointestinal illness. On July 11, the health department was notified that a stool specimen from one of the employees who attended the luncheon was positive for Cyclospora oocysts. Many others tested positive. It was subsequently revealed in a July 19, 1997, Washington Post story citing pesto_basil_cyclosporalocal health department officials that basil and pesto from four Sutton Place Gourmet stores around Washington D.C. was the source of cyclospora for 126 people who attended at least 19 separate events where Sutton Place basil products were served, from small dinner parties and baby showers to corporate gatherings. Of the 126, 30 members of the National Symphony Orchestra became sick after they ate box lunches provided by Sutton Place at Wolf Trap Farm Park.

In May 2001, 17 people in British Columbia were sickened with cyclospora associated with basil from Thailand. In 2005, 300 people in Florida were sickened with cyclospora from fresh basil.

My aunt was part of that outbreak.

Parasites. They’re everywhere.

Canadian researchers report in the Journal of Food Protection a “relatively high prevalence” of Cyclospora, Cryptosporidium and Giardia in ready-to-eat packaged leafy greens; most of the products were grown in the U.S.

Abstract below.

Detection of Cyclospora, Cryptosporidium, and Giardia in ready-to-eat packaged leafy greens in Ontario, Canada

Journal of Food Protection®, Number 2, February 2013, pp. 192-369 , pp. 307-313(7)

Dixon, Brent; Parrington, Lorna; Cook, Angela; Pollari, Frank; Farber, Jeffrey

http://www.ingentaconnect.com/content/iafp/jfp/2013/00000076/00000002/art00016

Numerous foodborne outbreaks of diarrheal illness associated with the consumption of produce contaminated with protozoan parasites have been reported in North America in recent years. The present study reports on the presence of Cyclospora, Cryptosporidium, and Giardia in precut salads and lettuceleafy greens purchased at retail in Ontario, Canada. A total of 544 retail samples were collected between April 2009 and March 2010 and included a variety of salad blends and individual leafy greens. Most of these products were grown in the United States, with some from Canada and Mexico. Parasites were eluted and concentrated before detection by PCR and immunofluorescence microscopy. DNA sequences were aligned with reference sequences in GenBank. Cyclospora spp. were identified by PCR-restriction fragment length polymorphism in nine (1.7 % ) samples and by DNA sequence analysis. Cryptosporidium spp. were identified in 32 (5.9%) samples; 29 were sequenced and aligned with the zoonotic species Cryptosporidium parvum. Giardia duodenalis was identified in 10 (1.8%) samples, and of the 9 samples successfully sequenced, 7 aligned with G. duodenalis assemblage B and 2 with assemblage A, both of which are also zoonotic. The presence of Cryptosporidium oocysts and Giardia cysts was confirmed in some of the PCR-positive samples using microscopy, while Cyclospora -like oocysts were observed in most of the Cyclospora PCR-positive samples. The relatively high prevalence of these parasites in packaged salads and leafy greens establishes a baseline for further studies and suggests a need for additional research with respect to the possible sources of contamination of these foods, the determination of parasite viability and virulence, and means to reduce foodborne transmission to humans.

314 sickened in 2010 outbreaks of Cyclospora infection on an Australian cruise ship

Gibbs et al. report in the March issue of Epidemiology and Infection that in 2010, an outbreak of cyclosporiasis affected passengers and crew on two successive voyages of a cruise ship that departed from and returned to love.boat.cyclosporaFremantle, Australia. There were 73 laboratory-confirmed and 241 suspected cases of Cyclospora infection reported in passengers and crew from the combined cruises.

A case-control study performed in crew members found that illness was associated with eating items of fresh produce served onboard the ship, but the study was unable conclusively to identify the responsible food(s). It is likely that one or more of the fresh produce items taken onboard at a south-east Asian port during the first cruise was contaminated. If fresh produce supplied to cruise ships is sourced from countries or regions where Cyclospora is endemic, robust standards of food production and hygiene should be applied to the supply chain.

Uncertainty and outbreaks of foodborne illness

Cyclospora in California strawberries in 1996 was Guatemalan raspberries.

Salmonella in tomatoes in 2008 was jalapeno peppers.

E. coli O104 in Spanish cucumbers was organic sprout seeds from Egypt.

Ron Doering, a past president of the Canadian Food Inspection Agency who practices food law in the Ottawa offices of Gowling Lafleur Henderson, LLP, writes in his monthly Food in Canada column that food safety regulators face “diabolical complexity when they carry out investigations characterized by deep factual and scientific uncertainty.”

“In the later two cases, investigators were dealing with rare strains of pathogens, and traceability was complicated by the fact that the source was unpackaged vegetables — without barcodes or lot numbers — that were quickly consumed, often with other produce. Microbiological testing proved quite unhelpful so investigators had to rely primarily on epidemiology. Pressed for “results,” both cases had regula¬tors initially jumping to the wrong conclusions, destroying in their wake the livelihood of many innocent people and seriously undermining the credibility of government food safety regulators. Both cases prove the “Iron Law of Food Safety Outbreak Investigations”— after the fact academ¬ics and the media will criticize government regulators either for overreacting or under-reacting.

“Perhaps government regulators have themselves to blame for the Iron Law because they continue to buy into the academic theory and language that they are engaged in risk management. They should be so lucky. The classical model of risk analysis falls far short in describing what reg¬ulators actually do and in providing much useful guidance on how they should do it. In both cases, regulators were not dealing with risk — a concept that surely involves at least some aspect of measuring probabilities — they were dealing with uncertainty and crisis management.

“The language of risk disguises the degree of ambiguity inherent in large-scale food safety investigations. “Risk” creates the illusion of precision, of assessing hazards in quantitative terms, or measuring the probability of harm. Science-based quantitative expert risk assessments often disguise the underlying subjective framework of assump¬tions and understate the high degree of uncertainty. Food safety risk assessors do not do double blind laboratory studies over a long period; they generally just review the conclusions of other scientists.

“In fact, in spite of their name, they typically do not even assess cases of risk, as calculations of probability are usually impossible to determine especially in the context of an urgent food safety crisis.

“The most that “risk assessors” can do is assess situations of uncertainty and then engage in a complex iterative process with decision-makers to try to find ways to man¬age an immediate issue fraught with multiple perspec¬tives where the science, however uncertain, is important but rarely determinative.

“Understanding what is going on is complicated too by everyone pretending the de¬cision is mostly science-based, unadulterated by policy considerations, and that they are managing the actual science-health risk, not the perception of risk.

“We need to abandon the language of risk and recognize that most food safety investigations are about issue man¬agement. We need to develop a new theoretical model and language that would borrow heavily from the emerg¬ing literature on adaptive management: in the face of such uncertainty, making policy choices and implement¬ing regulatory decisions should be recognized as neces¬sarily experimental; decisions are made that expect the unexpected; policies and regulatory responses are adapted as lessons are learned.

“The new model would also have to more fully recognize that while food safety must be paramount, trade-offs and weighing benefits are always a necessary part of the process. And this model would have to grapple with communicating this uncertainty to a generally scientifically illiterate consumer who simply expects retailers to only sell safe food and expects the regulatory system to guarantee it.”

Doering has some valid points. I don’t care what model is used as long as there is fewer sick people. Epidemiology, like humans, is flawed. But it’s better than astrology.

The more that public health folks can articulate when to go public and why, the more confidence in the system. Past risk communication research has demonstrated that if people have confidence in the decision-making process they will have more confidence in the decision. People may not agree about when to go public, but if the assumptions are laid on the table, and value judgments are acknowledged, then maybe the focus can be on fewer sick people.

On June 12, 1996, Ontario, Canada’s chief medical officer, Dr. Richard Schabas, issued a public health advisory on the presumed link between consumption of California strawberries and an outbreak of diarrheal illness among some 40 people in the Metro Toronto area. The announcement followed a similar statement from the Department of Health and Human Services in Houston, Texas, which was investigating a cluster of 18 cases of cyclospora illness among oil executives.

Turns out it was Guatemalan raspberries, and no one was happy.

Once epidemiology identifies a probable link between a food and some dangerous bug, health officials have to decide whether it makes sense to warn the public. In retrospect, the decision seems straightforward, but there are several possibilities that must be weighed at the time.

Back in 1996, when the Ontario Ministry of Health decided to warn people that eating imported strawberries might be connected to cyclospora infection, two outcomes were possible: if it turned out that strawberries were implicated, the ministry made a smart decision, warning people against something that could hurt them; if strawberries were not implicated, then the ministry made a bad decision with the result that strawberry growers and sellers lost money and people stopped eating something that was good for them.

If the ministry decided not to warn people, another two outcomes were possible: if strawberries were implicated, then the ministry made a bad decision and people could have acquired a parasitic infection they could have avoided had they been given the information (lawsuits usually follow); if strawberries were definitely not implicated then nothing happens, the industry does not suffer and the ministry does not get in trouble for not telling people.

These scenarios apply to any decision to go public.

It’s not that a new model is required – any model will do – as long as someone in some regulatory agency will put in writing the decisions involved in when to go public, with all assumptions laid bare. Then it can enter public discourse and be improved.

100 sickened with cyclospora at Georgia aquarium; it was the Wolfgang Puck food, not the fish

Channel 2 Action News has learned health investigators are looking into why more than 100 people got sick at a major Atlanta attraction.

The one thing everyone had in common was they all ate catered food at the Georgia Aquarium over the summer.

In the week of July 24, three groups had catered events at the aquarium. Two had corporate conferences, and there was a wedding reception, officials said. One or two weeks later people started coming down with week-long bouts of diarrhea.

The Georgia Division of Epidemiology said it is still investigating but told Channel 2’s Jeff Dore that cyclospora made the people sick, totaling well over 100 guests and staff.

Officials said they haven’t pinned the exact cause of the breakout, but did say the common food served at all three events was salad mix, fresh basil and cherry tomatoes.

Basil has a history of cyclospora outbreaks.

Wolfgang Puck catering prepares all the food at aquarium events, and its CEO took an overnight flight from California to talk with Channel 2.

Cyclospora associated with Mexican basil outbreak in Quebec, 2005

Milord et al write in the current issue of Epidemiology and Infection about an outbreak of Cyclospora cayetanensis amongst 250 patrons who ate at a Quebec restaurant in June 2005.

Cyclospora sp. was observed in the stools of 20 cases and 122 probable cases were identified.

Contaminated fresh basil originating from a Mexican farm, used to prepare an uncooked appetizer, was identified as the source.

 

No Chef’s Challenge this year after 200 sick with cyclospora last year

In May, 2010, at least 43 people were lab-confirmed to be sickened with cyclospora and over 200 displayed symptoms of illness after attending the Chef’s Challenge, a fundraiser for the Big Sisters of Sarnia-Lambton in Ontario, Canada.

"It wasn’t something we were able to go ahead with this year given the incident that took place," said executive director Kathy Alexander.

Local health types figured the source of the cyclospora was a cool pesto crunch but couldn’t identify the ingredient.
 

Cyclospora in Sarnia sickens 200, blamed on cool pesto crunch; health types can’t indentify ingredient; try basil

On July 7, 1997, a company physician reported to the Alexandria Department of Health (ADOH) that most of the employees who attended a corporate luncheon on June 26 at the company’s branch in Fairfax, Virginia, had developed gastrointestinal illness (Centres for Disease Control, 1997). On July 11, the health department was notified that a stool specimen from one of the employees who attended the luncheon was positive for Cyclospora oocysts. Many others tested positive. It was subsequently revealed in a July 19, 1997, Washington Post story citing local health department officials that basil and pesto from four Sutton Place Gourmet stores around Washington D.C. was the source of cyclospora for 126 people who attended at least 19 separate events where Sutton Place basil products were served, from small dinner parties and baby showers to corporate gatherings (Masters, 1997a). Of the 126, 30 members of the National Symphony Orchestra became sick after they ate box lunches provided by Sutton Place at Wolf Trap Farm Park.

In May 2001, 17 people in British Columbia (that’s in Canada) were sickened with cyclospora associated with basil from Thailand. In 2005, 300 people in Florida were sickened with cyclospora from fresh basil.

My aunt was part of that outbreak.

So when Lambton Community Health Services says it has closed its investigation of last month’s cyclospora outbreak in Sarnia, Ontario (also in Canada) that sickened more than 200 people and the suspect food was a cool pesto crunch (it was a chef showoff fundraiser), but can’t identify the ingredient, I’m leaning towards the basil.

Dudley Do-Right The Canadian Food Inspection Agency continues to investigate.

43 confirmed, 206 estimated sick in Ontario cyclospora outbreak at chef’s fundraiser

The source of last month’s outbreak of an intestinal parasite at a charity food event in Sarnia (Ontario, Canada) remains a mystery.

Public health officials questioned 286 of the more than 300 people who attended the Chef’s Challenge and found 206 became ill, said Andrew Taylor, Lambton County’s general manager of public health services.

Taylor said they also spoke with the event’s caterers and tested food samples.

“We were awaiting lab results until the end of last week and we were hoping that would be the home run,” he said, adding the results weren’t conclusive.

“The perfect investigation is where there’s illness, you identify the parasite at the source of the illness and then you link it to the food,” he said. “We have everything except the link to the food.”

Cyclospora is usually found in imported produce and contaminated irrigation water is often to blame, Taylor said.

A barfblog.com reader previously noted cyclospora is more of an environmental contamination issue than a hygiene issue. If the suspect food was something like raspberries, they are difficult to wash; basil or lettuces may be easier to wash but have a very large surface area and cyclospora is very very sticky. As with many other fresh produce outbreaks prevention on the farm is the best way to reduce risk.
 

Cyclospora strikes chefs’ event in Sarnia; almost 200 sick

On June 12, 1996, Ontario’s chief medical officer, Dr. Richard Schabas, issued a public health advisory on the presumed link between consumption of California strawberries and an outbreak of diarrheal illness among some 40 people in the Metro Toronto area. The announcement followed a similar statement from the Department of Health and Human Services in Houston, Texas, who were investigating a cluster of 18 cases of Cyclospora illness among oil executives.

Dr. Schabas advised consumers to wash California berries "very carefully" before eating them, and recommended that people with compromised immune systems avoid them entirely. He also stated that Ontario strawberries, which were just beginning to be harvested, were safe for consumption. Almost immediately, people in Ontario stopped buying strawberries. Two supermarket chains took California berries off their shelves, in response to pressure from consumers. The market collapsed so thoroughly that newspapers reported truck drivers headed for Toronto with loads of berries being directed, by telephone, to other markets.

However, by June 20, 1996, discrepancies began to appear in the link between California strawberries and illness caused by the parasite, Cyclospora, even though the number of reported illnesses continued to increase across North America. Texas health officials strengthened their assertion that California strawberries were the cause of the outbreak, while scientists at the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) said there were not yet ready to identify a food vehicle for the outbreak. On June 27, 1996, the New York City Health Department became the first in North America to publicly state that raspberries were also suspected in the outbreak of Cyclospora.

By July 18, 1996, the CDC declared that raspberries from Guatemala — which had been sprayed with pesticides mixed with water that could have been contaminated with human sewage containing Cyclospora — were the likely source of the Cyclospora outbreak, which ultimately sickened about 1,000 people across North America. Guatemalan health authorities and producers have vigorously refuted the charges. The California Strawberry Commission estimates it lost $15 million to $20 million in reduced strawberry sales.

Cyclospora cayetanensis is a recently characterised coccidian parasite; the first known cases of infection in humans were diagnosed in 1977. Before 1996, only three outbreaks of Cyclospora infection had been reported in the United States. Cyclospora is normally associated with warm, Latin American countries with poor sanitation.

One reason for the large amount of uncertainty in the 1996 Cyclospora outbreak is the lack of effective testing procedures for this organism. To date, Cyclospora oocysts have not been found on any strawberries, raspberries or other fruit, either from North America or Guatemala. That does not mean that cyclospora was absent; it means the tests are unreliable and somewhat meaningless. FDA, CDC and others are developing standardized methods for such testing and are currently evaluating their sensitivity.

The initial, and subsequent, links between Cyclospora and strawberries or raspberries were therefore based on epidemiology, a statistical association between consumption of a particular food and the onset of disease. For example, the Toronto outbreak was first identified because some 35 guests attending a May 11, 1996 wedding reception developed the same severe, intestinal illness, seven to 10 days after the wedding, and subsequently tested positive for cyclospora. Based on interviews with those stricken, health authorities in Toronto and Texas concluded that California strawberries were the most likely source. However, attempts to remember exactly what one ate two weeks earlier is an extremely difficult task; and larger foods, like strawberries, are recalled more frequently than smaller foods, like raspberries. Ontario strawberries were never implicated in the outbreak.

Once epidemiology identifies a probable link, health officials have to decide whether it makes sense to warn the public. In retrospect, the decision seems straightforward, but there are several possibilities that must be weighed at the time. If the Ontario Ministry of Health decided to warn people that eating imported strawberries might be connected to Cyclospora infection, two outcomes were possible: if it turned out that strawberries are implicated, the ministry has made a smart decision, warning people against something that could hurt them; if strawberries were not implicated, then the ministry has made a bad decision with the result that strawberry growers and sellers will lose money and people will stop eating something that is good for them. If the ministry decides not to warn people, another two outcomes are possible: if strawberries were implicated, then the ministry has made a bad decision and people may get a parasitic infection they would have avoided had they been given the information (lawsuits usually follow); if strawberries were definitely not implicated then nothing happens, the industry does not suffer and the ministry does not get in trouble for not telling people. Research is currently being undertaken to develop more rigorous, scientifically-tested guidelines for informing the public of uncertain risks.

But in Sarnia (Ontario, Canada) they got a lot of sick people who attended the Big Sisters of Sarnia-Lambton Chef’s Challenge on May 12, 2010.

The health department has completed interviews with over 270 people who attended the event. Of those people interviewed, 193 have reported being ill with symptoms consistent with cyclospora infection. There are currently 40 laboratory confirmed cases.

70 sick with cyclospora in Ontario after Big Sisters Chef’s Challenge

There’s nothing like a bunch of chefs getting together for a cook-off and making a bunch of the guests barf.

At least 70 people are sick after a Big Sisters "Chef’s Challenge" fundraiser on May 12 in Sarnia, Ontario (that’s in Canada).

Laboratory testing has confirmed at least seven cases of an intestinal infection caused by cyclospora, a single-cell parasite spread by people who consume food or water contaminated with feces.

Sorry for the Big Sisters, but poop happens.