Ten years ago, the picturesque farming town of Walkerton, Ontario, was plunged into a nightmare of food poisoning that sickened 2,300 residents, killed seven, and terrorized the town and its surroundings for weeks.


Eventually, the horrific outbreak of E.coli O157:H7 and Campylobacter was blamed on a small herd of grass-fed cows, a poorly planned town well and water system managers who didn’t take seriously the risks of foodborne illness.

Now, a decade later, Canadian researchers report that, in a very real sense, the epidemic continues.  Hundreds of survivors who thought they had recovered are at far greater risk of  hypertension, kidney disease and heart disease.  

Walkerton is a quiet town of about 4,800 people, nestled alongside the Saugeen River in the rolling alfalfa fields near the eastern shores of Lake Huron.  With its maple-lined streets, manicured lawns and brick storefronts, it could have been the set for Jimmy Stewart and “It’s a Wonderful Life.”

Until May of 2000, when it suddenly morphed into a science fiction horror story. 

The first indications came Thursday, May 18, when 20 children were absent from a local school and two were admitted to the local hospital with bloody diarrhea.  The next day, several residents of a retirement home fell ill with similar symptoms, and dozens more townspeople contacted their doctors about diarrhea, stomach pain and nausea.

 A local pediatrician suspected E. coli, and alerted local health officials, who began to investigate.  One official contacted Stan Koebel, manager of Walkerton’s water system. Koebel, who was responsible for chlorinating and testing the water, reported the town water was “OK.”  Another call later Friday got the same response.

In fact, investigators later learned, one of the town wells had been operated without chlorination for nearly a week, and a routine test by a private laboratory had shown up positive for E. coli.   But Koebel “withheld information from the health unit because he did not want health officials to know that he had operated without a chlorinator,” investigators reported.

Meanwhile, the epidemic worsened, inundating the local hospital and those in nearby towns. On Sunday, authorities confirmed at least two cases of potentially deadly E.coli 0157:H7, and advised residents to boil their water before using it.  The first person died on Monday, and six more in the following days.  Others were evacuated by helicopter to larger hospitals to be placed on kidney dialysis.

Walkerton’s tragedy became a huge news story in the Canadian press, with TV trucks, satellite dishes and floodlights on Main Street.  Reporters depicted a small town under siege by a mysterious epidemic, standing-room-only crowds at the hospital and helicopters whoof-whoofing overhead.

By that time, Koebel had resumed chlorinating the town water.  But it was too late.  Nearly half the town had already been sickened, 500 of them showing up at the hospital on Tuesday alone.  More than 20 children were on kidney dialysis machines.

Investigators showed up at Koebel’s office and found that sanitation reports had been falsified and altered for months or years.  And Koebel admitted that the water had tested positive for E. coli a week earlier, but he had not done anything about it.

A government investigation traced the epidemic to manure from a small farm adjacent to the town well just outside the town.  The well was contaminated during heavy rains in the weeks preceding the outbreak, and the lack of chlorine sealed the town’s fate.

Koebel and his brother, who also worked with the water utility, pleaded guilty to criminal charges stemming from the government investigation.

The Walkerton outbreak contradicted several myths or conventional wisdoms about E.coli 0157:H7 and foodborne illness in general.   In the 1990s, E.coli outbreaks were mostly attributed to undercooked hamburger, often from American fast-food restaurants; Walkerton had nothing to do with hamburger, nor fast food, nor American cows.

It also contradicted the assumption that deadly E.coli O157:H7 is a byproduct of industrial-level cattle-raising and overcrowded feedlots.  Walkerton’s cows were happy, grassfed cows that lived in a peaceful pasture just outside the town.

And now, a 10-year study of 1,977 Walkerton residents suggests that foodborne illness has consequences that last far beyond a mere tummy ache and a bout of diarrhea.  Conducted by doctors in London, Ontario, the study published in the British Medical Journal concluded that those who were sickened in 2000 experienced “an increased risk for hypertension, renal impairment and cardiovascular disease.”

“Our findings underline the need for following up individual cases of food or water poisoning by E.coli O157:H7 to prevent or reduce silent progressive vascular injury,” the researchers report.  “These long term consequences emphasize the importance of ensuring safe food and water supply as a cornerstone of public health.”