The Sun Times
The seven-year Walkerton Health Study showed about 65% of people in Walkerton got sick by drinking the deadly E. coli-laden water and nearly all recovered.
It found at least 3,000 people contracted intestinal illness during the E. coli outbreak, significantly more than is often quoted. Seven people died from the May 2000 outbreak.
“The vast majority of people, they’ve moved on. Their health is good,” said Dr. Bill Clark, who headed the study.
The study started with 4,300 people, including 1,000 who didn’t get sick. A diminishing number continued to participate in annual checkups between 2002 and 2008.
“There is a small minority of people who have significant problems,” Clark said.
The study helped catch and treat illnesses both brought on by the disaster and not, he said.
There were 27 children during the outbreak who developed kidney damage or hemolytic uremic syndrome. Now four remain on medication.
HUS is caused when a toxin produced by the E. coli. bursts blood vessels predominantly in the kidneys, though the gut, the brain and pancreas are also at risk.
With adult victims included there were 33 cases of HUS. One adult has unimproved kidney impairment, while two more have kidneys that are impaired but not significantly, Clark said.
“But the good news is, I think that very few if any will progress to end-stage renal (kidney) failure because we have identified and treated those at risk,” Clark said.
Based on the study, one child would be expected to develop diabetes and one did.
About 30% or 900 people developed irritable bowel syndrome in the initial outbreak. Very few children were afflicted with this uncomfortable problem, with urgent loose bowel movements and bouts of constipation.
Now about 100 people are left with it, as 50% improved every two to three years, Clark said.
Of those adults who got sick, there’s a 30% increased risk they’ll develop high blood pressure, a sign of worsening health that could lead to heart attack or stroke. It is a characteristic of the general population that one quarter will develop it.
So potentially that’s 110 more people will have high blood pressure due to the bad water, Clark said. But ongoing monitoring and treatment has improved their health significantly, he said. Drugs can prevent high blood pressure’s progression.
There remain increased risks of kidney impairment and cardiovascular problems though, Clark said.
The study also found a “significant increase” in inflammatory arthritis, or joint pain, affecting less than 100 people. Most people’s symptoms abated but the rest use medication.
Hopeful signs continue.
A study update in 2009 found 87% still in the study rated their health good-to-excellent. Of those remaining, who rated their health fair-to-poor, 49.4% said it was stable or better that year than in the previous year, Clark said.
Clark also said roughly two-thirds of people became sick to their stomach in the initial outbreak because they were genetically predisposed. One third of folks were less genetically vulnerable.
Clark said there wasn’t resistance in the population due to any past exposures to E. coli in the water, as some have suspected. That’s because the bug is so toxic that even a bit of E. coli O157:H7 in the water prior to 2000 would have produced the same disaster, Clark said.