text:  South Korea says North Korea has sent it more balloons carrying rubbish. Seoul is retaliating by broadcasting propaganda over loudspeakers aimed at the North. The Koreas are involved in an ongoing tip-for-tat campaign. Health officials in India's southern state of Kerala have issued an alert after a teenage boy died of the Nipah virus. Nipah is classified worldwide as a priority pathogen because of its potential to trigger an epidemic.