When the heads of the leading charities currently tackling the world’s most lethal but most neglected diseases met in Seattle this summer, their collective mood was mixed.

Bill and Melinda Gates pledge $500m to fight TB, Aids and malaria

They were attending a summit hosted by the Bill & Melinda Gates Foundation, the largest philanthropic organisation on the planet, which has helped substantially to boost funding and progress in developing new drugs, vaccines and diagnostics for infections such as HIV, tuberculosis and malaria