Polio had been battled to near-extinction after decades of effort, but this year the WHO confirmed 68 new cases and declared it an international public health emergency. Nearly 80 percent of those cases are in Pakistan.
Why is this? According to the New York Times' Donald McNeil Jr. (5/6/14), "Polio has never been eliminated there, Taliban factions have forbidden vaccinations in North Waziristan for years, and those elsewhere have murdered vaccine teams." McNeil also quotes a WHO spokesperson towards the top of the piece: "So we're saying to the Pakistanis, the Syrians and the Cameroonians, 'You've really got to get your acts together."'