As I was watching the Gates Malaria Forum's "Town Hall" yesterday evening (entire day's webcast), I was struck by an anecdote told by Brian Greenwood, Professor at London School of Hygiene & Tropical Medicine:
When Sir Ian McGregor was working in the Gambia, of the children who came to the clinic there with malaria, 80% had a positive blood film; 10 years ago it was 40% of those that had clinical malaria had a positive blood film; last year it was 4 percent.