A nightmare scenario of Ebola raging unchecked among millions of slum-dwellers in Africa's largest city has given way to a rare example of a victory over the virus.
Amid the gloom surrounding the escalating crisis in West Africa, developments in Lagos show how the right techniques at the right speed can bring about a welcome result.
With a population of more than 170 million, Nigeria is Africa's most populous nation and there were fears that Ebola would take hold when a Liberian-American arrived with the disease in July.
Instead, along with much smaller Senegal, Nigeria is now on the brink of being clear of the virus for a 42-day period at which point the World Health Organization (WHO) can declare it Ebola-free.
The outcome could so easily have been far uglier, and the fact that the news is happier is due to an astonishing story of medical detective work.
