Uganda discharged its last confirmed Ebola patient from Mulago National Referral Hospital in Kampala on Thursday 16 July, after two negative tests, and opened the 42-day countdown towards declaring its outbreak over1. Forty-two days is two maximum incubation periods for the virus, the interval WHO requires before an outbreak can be called finished. If the clock runs clean it expires around 27 August.
Uganda's final tally is 20 cases and 2 deaths, of which 15 were imported from DR Congo and 5 acquired locally, with no new case since 21 June2. That is a small outbreak handled quickly, in a country with a filovirus response apparatus built over five previous Ebola and Marburg emergencies, and it ends in the same week the epidemic across the border was ranked third-largest on record.
The fragility sits in the import route rather than in Uganda's own transmission. Fifteen of twenty cases arrived from DRC, and the countdown resets on a single new one. This outbreak has already travelled by air once, when a French doctor returning from the response tested positive in France on 24 June. Kampala's clock therefore depends on a transmission field on the other side of the border that the response can no longer map, which makes an unnoticed crossing, rather than a detected one, the likeliest way the 42 days end early.
