The Great Chipotle E. Coli Disaster of 2015 Is Over, Says CDC [Updated]

The great Chipotle disaster of 2015 seems destined to remain a mystery: The Centers for Disease Control is expected to close its investigation into the burrito chain's E. coli outbreak as early as today, according to the Wall Street Journal. Investigators have still been unable to determine which ingredient sickened dozens of people across nine states and landed 20 in the hospital.

The news caused Chipotle's stock to rise by five percent ahead of the market's official open this morning, and CNN Money speculates that "the worst may finally be over" for the chain; its stock price is currently down nearly 30 percent since news of the outbreak first surfaced back in October. But will the public feel comfortable returning to Chipotle without knowing what exactly caused the outbreak? The company has already implemented stricter food safety guidelines, but it's been waiting until the conclusion of the investigation to begin its full-on campaign to win back customers; expect that marketing venture to begin sometime this month.

Chipotle's troubles are far from over, however: The company is currently facing a federal criminal investigation over a 2015 norovirus outbreak that struck one of its California stores, not to mention numerous lawsuits from people who were sickened by either E. coli or a subsequent norovirus outbreak in Boston.

UPDATE 2/1 12:28 a.m.: The CDC has updated its Chipotle investigation page with the following statement: "These two outbreaks appear to be over. The most recent illness reported to CDC started on December 1, 2015." All in all, Chipotle's E. coli outbreaks sickened 60 people across 11 states and landed 22 in the hospital.