Salmonella sickens people in 12 states; USDA urges consumers to fully cook chicken dinners
This is one of those trends pieces. Salmonella cases have broken out in Minnesota. That in itself merits a news story. However, it has also sprung up in 11 other states, which the USDA did not name in its initial release warning about this contaminated chicken, which has mostly been in microwavable meals. A news story gains more prominence when it's effecting more people. A statewide trend becomes a national trend, and you've got the USDA releasing warnings and urging people not to trust chicken.
The story isn't written like a trends piece -- no anecdotal lead transitioning into "But Sally's case is like an alarming amount of others around the country" -- but the trend becomes the nut graf of the story, instead of just the nasty illness.