How Canadian health officials solved a deadly year-long listeria outbreak

When you hear of a virus outbreak, you think of a sudden explosion of sickness or a cluster of people infected. What you don’t think of is a process that lasts almost a full year, featuring infections spread across the country, month by month, that are ultimately traced to different contaminated products from different brands.

But when public health finally figured out in June what was causing a listeria outbreak that has killed three and sickened more than a dozen others, it did so by finally cracking what every one of those cases had in common and tracing the infections back to an unlikely source. 

Hannah Alberga is a health reporter for the Canadian Press.

“Given that there’s that 70-day incubation period [for Listeria], they won’t declare this outbreak until early October if this continues,” said Alberga.

So, how did health officials finally trace the outbreak back to an Ontario factory that packages plant-based milk?

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