Zipline International a Silicon Valley startup is using drones to deliver medicine and blood to patients in Rwanda, and it plans to expand to other countries by the end of the year. They announced this week that it will begin flying its drones in Rwanda in July, under a partnership with the government. The unpiloted autonomous vehicles will ferry supplies to hospitals and health centers across the tiny East African nation, forming what Zipline describes as the world’s first drone delivery system to operate at a national scale.