Liberia was officially declared Ebola-free on Thursday, the last country in West Africa to reach that milestone after more than 28,500 people were infected and 11,300 perished in the worst outbreak of the disease.
It was, in the words of the World Health Organization director-general, Margaret Chan, “a monumental achievement.”
Thousands of people infected with Ebola had to be tracked down, tested and treated. Tens of thousands of others who were exposed to the virus had to be located and monitored for up to 21 days, the incubation period of the virus.
But even after governments, aid agencies and health workers from around the world mobilized to defeat...