Robert Mugabe’s departure as head of state in Zimbabwe has been greeted with wild celebrations. Further north Ugandans are bracing themselves for a determined push by President Yoweri Museveni to extend his rule beyond three decades. Justin Willis, Gabrielle Lynch and Nic Cheeseman unpack Zimbabwe's lesson for Uganda: elections without choice have their uses, but they cannot ensure stable succession. Meanwhile the problems of absolute power loom large in Zimbabwe as Emmerson Mnangagwa prepares to take over as president. But, writes David B. Moore, that doesn’t mean that all is lost. Zimbabwean society has become more complex as years of democratic struggle have left their trace. This is the moment to push them to the fore.

Sustained investment as well as big scientific breakthroughs have led to enormous strides being made in the battle against HIV. But stigma is still preventing people from getting treatment and sticking to their drug regimens. As a result, Linda-Gail Bekker explains, the epidemic retains its powerful grip over the world. This is the first in a series of articles to be published ahead of World Aids Day on December 1.

Zanzibar has fought a long, well-documented battle with malaria. The Tanzanian archipelago has made big strides against the disease by providing bed nets and insecticides to millions of homes. Now epidemiologists and public health managers are looking to complement these approaches with outdoor based solutions. And, writes Andy Hardy, drones are a crucial part of their armoury - these eyes in the sky are able to track down the sometimes hidden watery spots where mosquitoes lay their eggs.