LANSING, Mich. — A top Michigan health official says she's cautiously optimistic that more residents took steps to combat the surging coronavirus last month, citing declining case rates. But chief medical executive Joneigh Khaldun warns that the spread remains significant and the effect of Thanksgiving won't be known for two to three weeks. Khaldun urges people who traveled for the holiday to stay away from others for 14 days. The governor says it's too early to say if her administration will extend a three-week order that prevents high schools from offering in-person instruction, prohibits dine-in service at restaurants and closes various entertainment businesses.