BEIJING — The virus-hit Chinese city of Wuhan, already on lockdown, banned most vehicle use downtown and Hong Kong said it would close schools for two weeks as authorities scrambled Saturday to stop the spread of an illness that has infected more than 1,200 people and killed 41. Hong Kong leader Carrie Lam said her government has declared the outbreak an emergency and will close primary and secondary schools for two more weeks on top of next week’s Lunar New Year holiday.