Southern Ontario Outbreak Over - "Fat Lady" Mute

December 9, 2008

The Ontario Ministry of Health declared last Friday that the province's multi-locus outbreak of E. coli O157:H7 has ended. 

With the most recent new patient having begun to experience symptoms on November 6, the tally of lab-confirmed and probable cases in each of the five public health units was finalized at:

• Niagara: 13 confirmed, 13 probable
  
• Guelph: 7 confirmed, 19 probable
  
• Halton: 6 confirmed, 6 probable
  
• Waterloo: 2 confirmed
  
• Hamilton: 1 confirmed
  

A confirmed case is one in which the outbreak strain of E. coli O157:H7 was recovered from a patient. A probable case is one in which the patient's symptoms and onset date fit the outbreak profile, but no lab confirmation was obtained. 

In all, 67 people were part of this outbreak; the outbreak strain of E. coli O157:H7 was recovered from 29 of them. But it was not found in any samples of food or water from any of the restaurants and food service venues. Nor was it isolated from the utensils, food contact surfaces or general environment in any of those locations. Epidemiological evidence, combined with a trace-back investigation carried out by the Canadian Food Inspection Agency, exposed a probable connection to lettuce grown in California's Salinas Valley.

Sadly, though not unexpectedly, investigators were unable to confirm the presence of the outbreak strain "down on the farm," leaving the Ontario Ministry of Health no real choice but to report,

"The source (or sources) of E. coli was not confirmed."

Southern Ontario E. coli O157:H7 Outbreak – Lettuce Liaison

For the second time this year, California lettuce is suspected of causing an outbreak of E. coli O157:H7 in Southern Ontario.

ThePacker.com, a produce industry news service, reports that FDA and the California Department of Public Health are investigating the possibility that romaine lettuce from one or more California farms may be linked to the current Ontario outbreak of E. coli O157:H7. The US action was triggered by epidemiological evidence from the Canadian outbreak investigation that pointed a finger at California romaine.

The outbreak has now spread to five different health units in Southern Ontario. As of Friday, November 21, 153 cases – 30 of them confirmed – have been reported. The cases are restaurant-associated, and the identical outbreak strain has been identified in all five health units.

Officials from the Canadian Food Inspection Agency, the Public Health Agency of Canada, the Ontario Ministry of Health and the five individual health units have all played a role in the investigation. CFIA told ThePacker.com that other possible food items are still under scrutiny, even as FDA and CDPH follow up on the lettuce lead.

As is so often the case in restaurant outbreak investigations, none of the food samples, environmental swab samples, or water samples have yielded the outbreak strain. Even if California romaine lettuce was the source of this outbreak, the odds are long that US authorities will be able to uncover the outbreak strain "down on the farm."

Southern Ontario E. coli O157:H7 - Is Lettuce The Link?

The Ontario Ministry of Health reported today that Southern Ontario's E. coli O157:H7 outbreak is responsible for as many as 148 illnesses in four health districts. These include:

• 56 cases in Niagara - 14 confirmed
  
• 31 cases in Halton - 6 confirmed
  
• 58 cases in Guelph - 7 confirmed
  
• 3 cases in Waterloo - 2 confirmed
  

By definition, a confirmed case is one in which the outbreak strain of E. coli O157:H7 was recovered from the patient. Unconfirmed cases are either still under investigation, or match the epidemiological profile (time frame, location, symptoms) without the specific outbreak strain having been found.

As is often the case in this type of investigation, the MOH totals vary somewhat from those reported by the individual districts – probably because of the time lag involved in transmitting updates to the province. Halton reported yesterday that they were investigating as many as 73 cases, including the six cases that have been lab-confirmed.

The geographic scope and size of the outbreak, while adding to the regulatory complexity, is a boon to the investigation. Epidemiologists can look for common elements, not only among the victims, but also among the food service establishments linked to the outbreak. And, based on a news release from the Canadian Food Inspection Agency, suspicion appears to have fallen on lettuce.

CFIA has not specified the type of lettuce, but a finger has been pointed at romaine. The federal agency is working on its traceback investigation while the provincial and district health authorities continue to follow up on interviews and lab confirmation of possible victims.

First Listeria monocytogenes, then E. coli O157:H7. Now all Canadians need is another Salmonella outbreak. Wonder whatever happened to the unexplained cases of Salmonella Poona that the Public Health Agency of Canada was worried about a few weeks ago?

Harvey's Reopens In North Bay

The North Bay-Parry Sound District Health Unit gave Harvey's the green light yesterday, and the restaurant has reopened for business. According to the North Bay Nugget, customers of the fast food outlet were standing in line by the time the restaurant opened its doors this morning.

Harvey's was ordered to close on October 12th, after it was linked to an outbreak of E. coli o157:H7 that sickened 251 individuals (50 lab-confirmed) in North Bay, 10 other Ontario health districts, Québec (1 case) and British Columbia (1 case). One of the victims, a seven-year old boy, is still hospitalized with in Toronto with hemolytic uremic syndrome. The source of the E. coli O157:H7 still has not been determined.

In what may be a coincidence – or perhaps a spurt of secondary infections – the district is investigating four possible cases of E. coli illness among four children in one Senior Kindergarten classroom at Sunset Park Public School. Children from that classroom have been asked to stay home while the classroom is thoroughly cleaned and disinfected. The Senior Kindergarten classes will resume tomorrow, but parents have been reminded to keep sick children at home.

While the District Health Unit says that its investigation into the Harvey's E. coli O157:H7 outbreak is continuing, chances are very slender that the source will ever be found – unless the same strain pops up again, either in North Bay or elsewhere.

E. coli O157:H7 - Tying Outbreaks Together

The E. coli O157:H7 cases in four southern Ontario regions may be linked to some cases in the United States after all – just not the ones we thought.

Bill Marler reported this morning that some isolates of E. coli o157:H7 that were reported in southern California, New Jersey and South Dakota appear to be the same genetic strain as the one that has infected individuals in Niagara, Halton, Waterloo and Guelph.

The Ontario Ministry of Health, which is coordinating the results from the affected regions, has recognized a total of 88 cases as of this evening, 24 of which have been lab-confirmed. The totals reported by each health unit are somewhat different:

• Niagara (as of November 7): 55 cases, including 13 confirmed, 38 probable and 4 under investigation
  
• Halton (as of November 10, 12:00pm): 69 cases under investigation, including 4 confirmed
  
• Guelph (as of November 10): 5 cases, all of which are lab-confirmed
  
• Waterloo (as of November 7): 2 cases, both lab-confirmed
  

The same genetic strain of E. coli O157:H7 has been isolated from at least one patient in each of these regional outbreaks. This outbreak strain is different from the strain isolated in the North Bay outbreak, as well as being different from the strain isolated earlier in the Chatham-Kent outbreak. The Chatham-Kent strain was identical to the outbreak strain associated with Aunt Mid's bagged iceberg lettuce.

With the attention now focused on the southern Ontario outbreak, it's easy to overlook the North Bay situation. But the victims of the North Bay outbreak deserve our attention – especially the family of Carter MacDonald, the seven-year old boy who suffered severe complications from his brush with E. coli O157:H7.

Carter developed hemolytic uremic syndrome as a result of his infection. He was airlifted to Toronto's Hospital for Sick Children on October 24, and placed into intensive care in "critical" condition. His condition has improved, but Carter remains hospitalized – his family at his side.

Carter's family has been depleting its savings in order to remain in Toronto with him. A fund-raising effort has begun in North Bay to help the family. The first to donate was the president of Harvey's Restaurant – the fast-food eatery that was linked to the outbreak.

Our thoughts this evening are with Carter and his family, and with all of the other victims of these outbreaks. 

E. coli O157:H7 Tours Ontario

Not content with wreaking havoc in North Bay, Niagara-on-the-Lake, Welland and Burlington, our old friend has also put in an appearance in Waterloo, Ontario. And, just for good measure, he has granted an encore at the University of Guelph.

Based on information released by the Ontario Ministry of Health, the illnesses in Niagara-on-the-Lake, Welland, Burlington and Waterloo all are due to the identical strain of E. coli O157:H7. So far, this multi-city outbreak comprises 91 cases, 20 of which have been confirmed. 

The two Waterloo victims are both described as "older children"; one has been hospitalized. Both of the Waterloo cases have been lab-confirmed.

The Little Red Rooster restaurant in Niagara-on-the-Lake, and M.T. Bellies in Welland, both of which closed for the outbreak investigation, have reopened after being given a go-ahead by the Niagara regional health authority. Johnathan's Family Restaurant in Burlington (Halton region) remains closed.

The University of Guelph outbreak may be completely unrelated to the other southern Ontario cases. It's still too early to tell. So far, four UoG students have fallen ill with E. coli O157; all of them ate at the Pita Pit in the University Centre. The University has closed the Pita Pit while the investigation into this outbreak is carried out.

The UoG campus was the scene of another E. coli O157 outbreak last July, when a group of international students was infected by the microbe. At least seven – possibly as many as 22 – of the Italian students became infected after eating food supplied by University Food Services. The source of that outbreak was never determined.

As for North Bay, that outbreak appears to be winding down. The last report, issued on Wednesday, indicated that no new lab-confirmed cases had been uncovered. And the source of the largest of the Ontario E. coli O157:H7 outbreaks remains a mystery.

Ontario E. coli O157:H7 Outbreak Links Clarified

We were advised this morning by Andrew Morrison of the Ontario Ministry of Health that a link between the Niagara and Michigan/Illinois outbreaks of E. coli O157:H7 has not been established. 

Here is what we know:

• The Chatham-Kent outbreak definitely was linked to the Michigan/Illinois outbreak.
  
• Preliminary genetic fingerprinting of some isolates from the North Bay outbreak showed a connection between the North Bay and Chatham-Kent strains. This was not borne out by more extensive testing.
  
• One isolate from the Halton outbreak appears to be the same as the Niagara outbreak strain.
  
• The Niagara cases have not been linked to the Michigan/Illinois outbreak strain.
  

Our thanks to Andrew Morrison for this clarification.

Niagara & Halton E. coli O157:H7 Linked to US Outbreaks

eFoodAlert has learned that the E. coli O157:H7 outbreak in the Niagara region has been linked by genetic fingerprinting to the recent cross-border outbreak that caused illnesses in Michigan, Illinois, Ohio, Oregon, New York and the Chatham-Kent region of Ontario.

The earlier outbreak was traced epidemiologically by US and Canadian investigators to California-grown bagged, pre-washed, shredded iceberg lettuce distributed by Aunt Mid's Produce Company of Detroit, MI. Investigators were unable to detect the outbreak strain in any samples of the lettuce, and Aunt Mid's never accepted the validity of the epidemiological findings.

As of early this afternoon, the Niagara region has identified 12 confirmed cases of E. coli O157:H7 infection; an additional 35 cases are under investigation. Of the 47 cases, 21 have been linked to the Little Red Rooster in Niagara-on-the-Lake and 21 to M.T. Bellies in Welland. Both restaurants closed voluntarily to assist the investigation. Little Red Rooster has been given the go-ahead to reopen tomorrow; M.T. Bellies remains closed except for its bar, which has been open for business throughout this investigation.

There is a good chance that the Halton region outbreak also is related to the contaminated lettuce. E. coli O157:H7 isolated from one of the cases in the Halton region outbreak is a genetic match for the Niagara outbreak strain. As of yesterday, 28 cases – linked to Johnathan's Family Restaurant in Burlington – were under investigation. Additional genetic fingerprinting results should be available by the end of this week. 

The North Bay outbreak, though, is still a mystery. None of the E. coli O157:H7 isolates from North Bay match the outbreak strain from Niagara, Halton or Chatham-Kent. We've been told by Andrew Morrison (Media Relations Coordinator for the Ontario Ministry of Health and Long Term Care) that the following Ontario health districts have reported one or more cases that are linked to the Harvey's Restaurant in North Bay. In addition, one case has been reported from British Columbia, and one from Centre de Santé Temiscaming in Québec.

• North Bay-Parry Sound (40 confirmed, 163 suspect)
  
• Timiskaming (2 confirmed, 9 suspect)
  
• Sudbury (3 confirmed, 11 suspect)
  
• Porcupine (1 confirmed, 7 suspect)
  
• Hastings-Prince Edward (1 confirmed)
  
• Simcoe-Muskoka (1 suspect)
  
• Toronto (1 suspect)
  
• Niagara Regional Health Unit (1 confirmed, 1 suspect)
  
• Durham (1 suspect)
  
• Peel (1 suspect)
  
• Haliburton-Kawartha Pine Ridge (1 confirmed)
  

Federal, provincial and district health investigators are examining the possibility of a common food source for the Niagara and Halton outbreaks. So far, according to Morrison, no food items have been identified. But epidemiological and lab analyses are continuing. More information should become available by week's end.

It's anybody's guess, though, when – if ever – investigators will be able to identify the source of the North Bay outbreak.

Ontario E. coli O157:H7 Investigations Continue

North Bay-Parry Sound reported today that it has now identified 246 cases – 49 lab-confirmed as E. coli O157:H7 – in the food poisoning outbreak linked to Harvey's Restaurant on Algonquin Avenue in North Bay, Ontario. This includes cases from 10 other Ontario District Health Units, as well as from the provinces of Québec and British Columbia. The District still has not been able to identify a probable source of the contamination.

The Niagara region outbreak has now grown to 46 cases, 12 of which are lab-confirmed. Forty-one of the 46 cases have been linked to one of two restaurants – Little Red Rooster in Niagara-on-the-Lake, and M.T. Bellies in Welland. 

Halton's caseload also is growing. The total number of suspect and confirmed cases now stands at 28, three of which have been lab-confirmed as E. coli O157:H7. This outbreak has been linked to Johnathan's Family Restaurant, in Burlington.

It's still not clear to what extent these three outbreaks of E. coli O157:H7 illness are interconnected. According to test results reported by Niagara, that outbreak is unrelated to the North Bay illnesses. But there is no information yet on whether the Halton outbreak is due to the same outbreak strain detected in victims of either the Niagara or the North Bay outbreaks. We should know more by the end of this week.

Another Ontario Restaurant Enmeshed in E. coli O157:H7 Outbreaks

North Bay-Parry Sound reported this afternoon that the number of E. coli O157:H7 cases has risen to 237, of which 46 have been lab-confirmed. All of the confirmed cases are linked directly to the Harvey's Restaurant on Algonquin Avenue in North Bay, and reported an onset of symptoms before October 22nd.

The District Health Unit has received lab reports on food samples up to October 25th. All of the food samples analyzed so far have been negative for E. coli O157:H7. Some tests, though, are still in progress.

The 237 cases include residents of North-Bay Parry Sound, nine other Ontario District Health Units, and two other provinces – Québec and British Columbia. All of the districts have supplied North Bay with information obtained from people who ate at Harvey's during the time period of the outbreak and who did not become ill. This information is being combined with information obtained from confirmed and suspected outbreak cases in the hope that the data will point to a probable source of the outbreak strain.

Meanwhile, the investigation into a separate outbreak of E. coli O157:H7 in the Niagara region is continuing. The number of cases in that outbreak has risen to 36 – 9 confirmed and 27 under investigation. Of the 36 cases, 20 have been linked to the Little Red Rooster restaurant in Niagara-on-the-Lake, and 12 to M.T. Bellies in Welland. Both restaurants have closed and are cooperating in the investigation.

Yesterday, yet another Ontario health unit reported a restaurant-associated outbreak of E. coli O157:H7. Halton Region is investigating five cases – 2 confirmed and 3 suspected – that have been linked to Johnathan's Family Restaurant, 4121 Fairview Street, Burlington. The restaurant has closed pending the outcome of the investigation. 

The Halton Health Department is asking anyone who ate at Johnathan's between October 13 and October 30, and who subsequently experienced symptoms of E. coli O157:H7 gastroenteritis (nausea, diarrhea (possibly bloody), stomach cramps or vomiting), to see their doctor and also to contact Halton Region at (905) 825-6000 or 1-866-442-5866.

It's too soon to know whether the Halton outbreak is due to the same strain of E. coli O157:H7 as the Niagara region outbreak. If all three restaurants – each located in a different town – have been victimized by the same strain of E. coli O157:H7, this would point to a common food source for the microbe.

It shouldn't take more than a week or so for Halton to obtain genetic fingerprinting of its outbreak strain. In the meantime, both the Niagara and Halton regions will be beating the bushes to find and interview additional victims.

Ontario E. coli O157:H7 Outbreaks Still Under Investigation

The news releases from the North Bay-Parry Sound District Health Unit are getting more terse as time passes without a breakthrough in the E. coli O157:H7 outbreak investigation. Today's release – except for the usual cautions about hygiene – reads:

"There are now 235 cases, of which 45 are lab confirmed for E. coli O157:H7. All confirmed cases are linked to Harvey’s North Bay and had an onset of symptoms before October 22, 2008. This includes cases from 9 other Ontario Health Units, Quebec and British Columbia. The investigation is ongoing, at this point; no product or process has been confirmed as the source of the outbreak."

Today's news releases from the Regional Municipality of Niagara was meatier. The total number of cases of E. coli O157:H7 in the Niagara region outbreak now stands at 31 – 9 confirmed, and 22 under investigation. Eighteen of the 31 cases have been linked to the Little Red Rooster restaurant in Niagara-on-the-Lake and 9 have been traced to M.T. Bellies in Welland. Both restaurants have closed, although the bar at M.T. Bellies remains open.

Niagara also reports that preliminary genetic fingerprinting of their outbreak strain indicates that it is not the same as the North Bay strain. There has been no confirmation of this from North Bay, which has remained silent on the progress of genetic fingerprinting, even though eFoodAlert has questioned them directly on more than one occasion.

According to the news update, the Niagara region outbreak is not associated with municipal drinking water supplies. Lab tests are in progress on food samples from both restaurants, but no results have been released. The owners of both restaurants are reported to be cooperating in the investigation.

The Niagara Region Public Health authorities are asking any residents or visitors who have experienced bloody diarrhea on or after October 11, 2008 to visit their family physician or a walk-in clinic, as they may be suffering from an infection with E. coli O157:H7. 

E. coli Turns Up In Niagara-On-The-Lake, Too

The Niagara Region Medical Officer of Health is asking members of the public to contact the health unit if they experienced an onset of symptoms of E. coli  illness – severe abdominal pain and bloody diarrhea, possibly accompanied by fever – between October 11th and October 24th.

The request was made after two people were lab-diagnosed with E. coli . An additional three people are also thought to be infected with the microbe. Four of the five victims ate at the Little Red Rooster, 271 Mary Street, Niagara-on-the-Lake. The Health Unit's news release did not specifically mention E. coli O157:H7, but bloody diarrhea is a common symptom of this strain.

The restaurant's owners are cooperating with the investigation into these illnesses, including providing food samples for analysis and giving investigators unimpeded access to the restaurant. The link between this outbreak and the Little Red Rooster is not yet certain. The Health Unit is also investigating other possible leads, and hopes that more victims will come forward. With a larger data base, a source for the outbreak can be identified with greater confidence.

While the Niagara Region is focusing on its newly identified outbreak, the North Bay-Parry Sound District Health Unit continues to plug away at what is at risk of becoming another microbiological cold case. Forty-two cases have now been lab-confirmed in the North Bay outbreak, out of a total of 217 suspected and confirmed cases. Victims of this E. coli O157:H7 outbreak have been reported from eight other Ontario District Health Units, in addition to Québec and British Columbia.

Today's update from North Bay provided encouraging news about the child who was hospitalized in critical condition after developing hemolytic uremic syndrome. That child, while still hospitalized, has improved and is no longer in critical care.

Epidemiologists say that they received many telephone contacts from healthy people who ate at the Harvey's Restaurant that is the focus of this investigation, and have enough information to carry out their statistical study. 

As yet, "... no specific product or process..." has been identified as the source of the infections. The Ontario Ministry of Health is reviewing test results from this outbreak to determine whether it is linked to any other outbreaks or sporadic cases of E. coli O157:H7. 

North Bay, Ontario Outbreak: No News Is Bad News

Today's update from the North Bay-Parry Sound District Health Unit is singularly devoid of news – good or bad.

The number of confirmed and suspect cases has risen slightly to 209, of which 39 have been lab-confirmed as E. coli O157:H7. One of the victims is a child, who is hospitalized with symptoms of hemolytic uremic syndrome. Today's update describes the child's condition as "critical".

There still has been no break-through in finding the source – food, food-handler, or environmental – of the outbreak. And there is still no word on the results of genetic fingerprinting of the outbreak strain (or strains).

Unless something significant breaks over the weekend, it's likely that the next update from the District Health Unit will be on Monday, October 27th.

North Bay E. coli O157:H7 Victim Hospitalized in Serious Condition

North Bay-Parry Sound District Health Unit announced today that one of the victims of the Harvey's Restaurant outbreak – a child – is hospitalized in serious condition with hemolytic uremic syndrome (HUS).

The child is one of 207 confirmed and suspect cases of E. coli O157:H7 illness, most of them traced to customers who ate at Harvey's Restaurant on Algonquin Avenue in North Bay, Ontario between October 1st and October 12th. Thirty-nine of the victims have been lab-confirmed.

Investigators have not yet determined a probable source of the pathogen. The District Health Unit has asked customers of Harvey's Restaurant, who ate there between October 1st and October 12th and remained healthy, to participate in an epidemiological interview. The interviews will help the District Health Unit to identify possible sources of the outbreak.

There is still no report from the Health Unit as to the results of genetic fingerprinting of the E. coli O157:H7 isolates that have been recovered from patients. This information, too, may help investigators to key in on a source.

At last report, eight other District Health Units in Ontario have reported one or more possible victims of this outbreak. One case also has been reported from Québec. Under the circumstances, it's surprising that the Ontario Ministry of Health hasn't taken a more active role in reporting the status of the outbreak investigation.

North Bay E. coli O157:H7 Outbreak: New Cases Come To Light

The North Bay-Parry Sound District Health Unit reported today that the total number of confirmed and suspect cases in this outbreak investigation now stands at 190 – up significantly from yesterday's total of 158. Thirty-six of the 190 cases are lab-confirmed as E. coli O157:H7. 

We've been told by the District that confirmed cases are defined as patients from whom E. coli O157:H7 has been isolated; suspect cases are patients whose symptoms match those expected from an infection with E. coli O157:H7, and who began to experience their symptoms during the outbreak time frame. As of today, no genetic fingerprinting (PFGE) results are available. 

The Medical Officer of Health believes that the sharp increase in cases is due to more cases coming out of the woodwork as the news of the outbreak continues to spread through the province. In addition to North Bay, suspect cases have been reported in eight Ontario health districts. Québec, too, has reported at least one case.

We've learned that the other districts reporting one or more cases possibly linked to this outbreak include Sudbury, Porcupine, Timiskaming, Simcoe-Muskoka, Hastings Prince Edward County and York Region. There is no indication whether any of these cases have been confirmed.

The investigation into the source of the outbreak seems an eerie parallel of the Oklahoma E. coli O111 outbreak investigation earlier this year. Most of the victims ate at the same restaurant – Harvey's North Bay – within a fairly narrow time frame. Tests of food and water samples so far have failed to detect the presence of E. coli O157:H7. The District has not yet released information on the investigation into food handlers as a possible source, except to say that the restaurant and its employees are cooperating.

The District Health Unit is continuing to interview suspect victims of this outbreak, in the hope of determining what food or foods might be the source of the infections. Investigators are actively seeking the assistance of anyone who ate at Harvey's Restaurant on Algonquin Avenue in North Bay between the dates of October 1st and October 12th. By comparing the items eaten by those who became ill and those who remained healthy, investigators might be able to determine the source of the E. coli O157:H7. People who fall into this category are asked to contact the North Bay-Parry Sound District Health Unit at (705) 474-1400 or (800) 563-2808.

Unfortunately, epidemiological analysis is chancy under these circumstances. In a fast food burger restaurant like Harvey's, most people order similar meals. And not everyone will remember what toppings they had with their burgers, or whether they had a salad. The longer it takes, and the more complex the investigation, the less likely that a definitive answer will be forthcoming.

The best chance of determining the source of the outbreak is if the outbreak strain can be matched genetically to a previously isolated E. coli O157:H7 from a recent food recall or a recent outbreak elsewhere. Otherwise, the North Bay outbreak may simply be added to a long list of "unexplained outbreaks."

North Bay Outbreak Numbers Rise Again

The North Bay-Parry Sound District Health Unit reported this afternoon that the number of confirmed cases in this E. coli O157:H7 outbreak has risen to 35 lab-confirmed victims. The combined total of confirmed and suspect cases now stands at 158.

The total number of cases is now just one shy of the 159 total that was reported on Sunday. eFoodAlert has learned that the removal of 18 suspect cases from the Sunday total was due to the symptoms reported by those individuals not matching the typical symptoms associated with an E. coli o157:H7 infection. 

In addition to North Bay-Parry Sound, eight other health units in the province are investigating cases that may be part of this outbreak. The Ontario Ministry of Health, Canadian Food Inspection Agency, Public Health Agency of Canada and Agency for Health Protection and Promotion are all involved in the investigation.

So far, investigators have not been able to key in on a single source. Food samples taken on October 12th, when Harvey's – the North Bay restaurant at the center of this investigation – closed, have all tested negative for E. coli O157:H7, according to a report by Colin Perkel of The Canadian Press.

The District Health Unit should soon be receiving the results of genetic fingerprinting of the E. coli O157:H7 recovered from the first batch of confirmed cases. If the outbreak strain matches a strain of E. coli O157:H7 recovered from another recent outbreak or from other sporadic cases elsewhere in Canada, this investigation will be on the road to success. But if the fingerprint does not match any other recently recovered E. coli o157:H7 isolate, the chances of finding the source of the North Bay outbreak will be considerably reduced.

As we found out during the Maple Leaf Listeria monocytogenes outbreak, Ontario does not have the capability of carrying out PFGE – genetic fingerprinting – analysis on bacteria. Unlike Québec, the province of Ontario relies on a federal lab, based in Winnipeg, for PFGE analyses. Even with overnight delivery of cultures, this can add days to the time required to obtain results.

Canada's largest province should invest in its own PFGE lab capabilities. In an outbreak investigation, time is always of the essence.

North Bay Shrinks; Snohomish Grows

The magnitude of the North Bay E. coli O157:H7 outbreak has decreased slightly, according to today's news release from the North Bay-Parry Sound District Health Unit. The district now puts the tally at 141 cases, 28 of which are lab-confirmed for E. coli O157:H7. The 18-case reduction came after health investigators determined that those individuals were not part of the outbreak.

The daily releases from the District Health Unit are frustratingly vague. Notably, the definition of "confirmed" and "suspect" is unclear. No mention has been made of genetic fingerprinting of the E. coli O157:H7 isolated from patients. Were the 18 cases eliminated, for example, because they were infected with a different strain of E. coli O157:H7, or were they suffering from a completely unrelated cause of gastroenteritis?

All of the illnesses appear to be linked to the same North Bay restaurant, although some of the cases may be secondary infections transmitted to a family member or care-giver. There has not yet been a breakthrough in the investigation into the source of the outbreak. And, as was the case in the Oklahoma E. coli O111 outbreak, the longer it takes, the less likely it is that a probable source will be found. The District Medical Officer of Health already has cautioned the public that we may never know what caused the outbreak.

While the North Bay investigation limps along, there is a growing outbreak of suspected E. coli gastroenteritis in Snohomish County, Washington. 

The Snohomish Health District reported today that it is investigating a cluster of 14 possible cases of E. coli infection. All of the victims fell ill in a one-week period between October 7 and October 14. No common source has been determined yet, and lab confirmation of the infections is still in progress. 

Victims have reported symptoms of bloody diarrhea and stomach cramps, with little or no fever. These symptoms are consistent with E. coli O157:H7. They can also be the result of an infection with other E. coli serotypes that generate similar toxins – E. coli O111, for example. 

The outbreaks – like the microbes that cause them – keep multiplying.

E. coli O157:H7 – North Bay And Elsewhere

The  number of cases in the North Bay, Ontario E. coli O157:H7 outbreak has increased to 159 confirmed and suspected cases, according to a news release from the North Bay-Parry Sound District Health Unit. This is up from yesterday's reported total of 146 cases.

Twenty-six of the cases have been lab-confirmed as E. coli O157:H7, and the 159 cases are now spread over seven health districts, including North Bay-Parry Sound, Algoma, Sudbury, Timmins, Simcoe and Toronto. 

A CBC news report suggests that the location of North Bay at the intersection of Hwy 11 and Hwy 17 – two branches of the Trans Canada Highway – may have contributed to the dissemination of this outbreak to other parts of Ontario.

As we hinted at yesterday, the North Bay news releases are starting to take on the same tone as the daily news updates in last month's Oklahoma E. coli O111 outbreak. In today's update, the District Medical Officer of Health, Dr. Catherine Whiting, offered the following caution.

"We are doing everything we can to look for the specific source of the E. coli. However, in the majority of these types of outbreaks, despite everyone’s best efforts, the specific source is never found.”

This fall has produced a bumper crop of E. coli O157:H7 outbreaks in the United States and Canada. In addition to recent outbreaks in Michigan, Illinois, Colorado, Vermont and North Bay, health officials in Snohomish County, Washington and Lee County, Iowa also are investigating flare-ups.

As for the North Bay outbreak, the District Health unit points out that the rate of new cases seems to have fallen, signaling that the outbreak may have passed its peak. That's the good news. The bad news is that the shorter-lived the outbreak, the harder it can be to pinpoint the source.

North Bay, Ontario: E. coli Déjà Vu?

A large number of patrons of a single restaurant fall ill within a short time window. A broad range in victims' ages – 1 year to 90 years. Water supply has been checked and cleared. No answers on the source.

If this is starting to sound familiar, you probably were reading my posts last month on the Oklahoma restaurant-associated outbreak of E. coli O111. Except that, this time, we are dealing with E. coli O157:H7, and the outbreak is taking place in and around North Bay, Ontario.

The North Bay outbreak has expanded to include 146 confirmed and suspect cases. The illnesses have been linked to a Harvey's restaurant outlet in North Bay. But that's as far as the District Health Office's epidemiologists have progressed.

Samples of municipal drinking water – the restaurant did NOT use well water – have been tested and cleared. The employees are being questioned, and have cooperated in the investigation; stool samples are being analyzed. Victims have been interviewed. No clear source of the pathogen has yet emerged.

Of the 146 victims, 24 have been lab-confirmed for E. coli O157:H7. Some have been hospitalized, but most are recovering at home. Six other Ontario health units – including Algoma, Porcupine, and Sudbury – are now investigating cases of gastroenteritis that may be linked to the North Bay outbreak. 

Unless the genetic fingerprint of the North Bay outbreak strain is matched to a strain of E. coli O157:H7 that was isolated elsewhere – perhaps, Aunt Mid's lettuce? – the North Bay-Parry Sound District Health Unit might have no more success in tracing the source of the outbreak strain than did the investigators of the Oklahoma E. coli O111 outbreak.

North Bay, Ontario E. coli O157:H7 Outbreak Grows

The E. coli O157:H7 outbreak in North Bay, Ontario has grown to 131 cases. Twenty-two people have been confirmed by lab analysis to have been infected with E. coli O157:H7. An additional 22 people are still under investigation. It's unclear from the most recent reported posted released by the North Bay-Parry Sound District Health Unit what the status is of the other 87 cases.

While most of the victims are in North Bay, an unspecified number of the 131 cases have been reported from four other health districts. The Algoma, Porcupine and Sudbury Health Units all are investigating illnesses that may be related to this outbreak.

Although the outbreak has been traced to a specific restaurant – Harvey's – in North Bay, there is no news yet as to the source of the E. coli O157:H7. The restaurant has been closed since Sunday evening, and restaurant employees are cooperating in the investigation. 

Although most healthy adults can shrug off an infection with E. coli O157:H7 as an unpleasant inconvenience, children are especially at risk of both short-term complications – hemolytic uremic syndrome – and long-term chronic aftereffects. 

E. coli O157:H7 is not to be taken lightly, especially when it strikes children and the elderly. A follow-up study of victims of the Walkerton, Ontario E. coli O157:H7 outbreak was just released. The seven-year study found that 22 children who were infected in 2000 developed permanent kidney damage. Anyone who experiences symptoms consistent with E. coli O157:H7, including diarrhea – especially bloody diarrhea – stomach cramps, nausea and vomiting, should be seen by a doctor without delay.