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IHA explains process for issuing public alert
The fact there were no ‘clusters’ of E. coli cases reported meant the public was not informed earlier of the health hazard related to gouda cheese from Salmon Arm.
The E. coli-related illness was first reported in July, with the majority occurring at the end of August and beginning of September. A public statement was issued Sept. 17.
The Interior Health Authority stated that when the onset occurred in July, it was a cause for concern but, as an isolated case, did not ring alarm bells. The province gets a number of E. coli cases throughout the year and, while they try to identify the source, people are sometimes unable to pinpoint the cause of the illness.
It takes anywhere from two to four weeks from the time a person gets ill to get the bacteria fingerprinting done and matched.
In terms of the outbreak linked to Gort’s, health officials saw a cluster developing only the week of Sept. 9, said Dr. Rob Parker, IHA medical health officer.
Parker describes the process and time required to determine Gort’s as the suspected source of the e.coli 0157:H7 outbreak.
He says IHA gets anywhere from 15 to 20 cases a year, more often in summer than winter.
“As soon as we get lab confirmation, we follow up the same or next day, asking people what they might have eaten, have they been around farm animals, travelling,” Parker said, noting symptoms occur usually within two to four days but as long as a week after ingestion.
Getting an indication that e.coli is the culprit takes longer as it usually takes a protracted case of diarrhea or bloody diarrhea to convince many people to go to their doctors.
Blood tests are taken and by the time the results are in, there can be a three-week delay. Asking people to remember what they ate that long ago often does not provide useful data. Lab results that are positive for e.coli O.157 are sent to the B.C. Centre For Disease Control where they are fingerprinted – in a format that resembles a retail item barcode.
The “fingerprints” are shared across Canada, with the provinces and the federal government watching for clusters of the same fingerprint.
“That’s what happened here, some Alberta people matched up,” Parker. “Nobody immediately identified Gort’s, but when asked, they all said yes and by Tuesday morning (Sept. 17) it was clear we had to warn people.”