. >> reporter: vol advertiser phones as the florida senator also tried to stand up a ground game in the home stretch. chris christie, attending his 65th town hall, warned voters about candidates like trump and rubio, who have not invested as much time in the granite state. >> if you reward those folks who don't show up here, there's no reason-- there's no reason for new hampshire to be first. >> reporter: john kasich is in the middle of his 100th town hall. he doesn't have the poll numbers here that rubio does, but he doesn't necessarily need to. scott, the way rubio and kasich finish in this state, because kasich has the best organization, will tell a lot in the future about politicking for the presidency here in new hampshire. >> pelley: major garrett, thank you. the zika virus, suspected of causing birth defects, is now in 26 countries and territories in the americas. two new cases in florida now bring the total in the u.s. to at least 53. zika is most often spled by mosquitoes, but today, the aimed at transmission through sex. our dr. jon lapook is in brazil, the country hardest hit by the outbreak. >>