20:32DiscoveryPatient zero: Back from the brinkBBC World Service Duration: 41 minutes Mon 24th May 2021, 20:32 on BBC World Service East and Southern AfricaAvailable for over a yearListen nowWhy did children in PNG contract polio in 2018? Show more GenresFactualScience & NatureFormatsMagazines & ReviewsBrandDiscovery Source: BBC Online