Set in a dry and dusty landscape, Mongo is a town of 40,000 people, in Chad, a landlocked country in central Africa. Average life expectancy, at 51, is about 30 years lower than in the UK.

About 50 cases of measles were confirmed within the past two weeks, said Oumar Mahamat Traore, chief health official in Bologo, appointed by Chad's central government in N'djamena. He said the ...