City water not the culprit in cluster of illnesses after Thanksgiving
A cluster of gastroenterological (GI) illness reported at the Kootenay Boundary Regional Hospital on Oct. 13 and 14 were not caused by contaminated water in Castlegar, despite rumours to the contrary.
Medical Health Officer Dr. Sue Pollock said IHA received a report from the hospital about a small cluster of patients suffering from GI symptoms, and vigorously investigated the possible cause.
“When we get these reports, we take them very seriously,” Pollock said. “What we look for is commonalities between the individuals that might describe what’s happening.”
She said investigation and laboratory testing did not identify any common source or organism to connect any of the impacted individuals with one another. They also compared their laboratory results to previous months and did not find anything unusual to indicate a larger problem.
“We do tend to see an increase in GI illness associated with the holidays,” she said (this cluster was in the two days following Thanksgiving). “And this is a time of year we tend to see an increase in GI illnesses such as Norwalk or Norovirus.”
Had the cause been contaminated water, Pollock said, she would have expected labs to be able to isolate a single organism.
“I would also expect a much higher number of people presenting (with symptoms),” she added.
The source of the confusion may have been a brief interruption in the city’s chlorination system that spurred officials to issue a water quality advisory on Oct. 8 (click here for that coverage). But, while chlorine residual levels did drop below recommended levels, the water available to residents had still been treated with UV filtration, a redundancy in place to prevent any kind of contamination.
Furthermore, according to Public Works director Chris Barlow, the reservoirs and mains still contained chlorinated water, and the unchlorinated slug of water was flushed from the system within hours. The water was travelling through a closed system with sterile pipes that are constantly bathed in chlorine, so the chance of any kind of contamination that would cause GI illness in residents is slim to none.
As it stands, Pollock assured residents that IHA diligently monitors, investigates and follows up any reports they get that might reflect a public health concern.