The National Geographic Channel is airing a new four-parter, Microkillers, beginning Sunday, Jan. 22 at 8 p.m. Episodes look at ‘Malaria & Plague,’ ‘Ebola,’ ‘Superflu,’ and ‘TB.’ The show airs as part of ‘Microkillers Week,’ which also features specials on the deadly world of viruses. The Microkillers eps will repeat on Sunday, Jan. 29, beginning at noon.