The threat carried by a tiny, day-biting, house-loving mosquito has created a new wrinkle in the back-to-school preparation for 187 Palm Beach County campuses where some 190,000 children are due to return Monday. This week, with the news that one of the county’s residents is among those believed to have contracted Zika locally, Gov. Rick Scott unveiled a campaign to battle the scourge from Martin to Monroe counties with pre-packaged lessons on the dangers of standing water and cases of bug spray to be delivered to school doors upon request.